src/3rdparty/sqlite/sqlite3.h
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     1 /*
       
     2 ** 2001 September 15
       
     3 **
       
     4 ** The author disclaims copyright to this source code.  In place of
       
     5 ** a legal notice, here is a blessing:
       
     6 **
       
     7 **    May you do good and not evil.
       
     8 **    May you find forgiveness for yourself and forgive others.
       
     9 **    May you share freely, never taking more than you give.
       
    10 **
       
    11 *************************************************************************
       
    12 ** This header file defines the interface that the SQLite library
       
    13 ** presents to client programs.  If a C-function, structure, datatype,
       
    14 ** or constant definition does not appear in this file, then it is
       
    15 ** not a published API of SQLite, is subject to change without
       
    16 ** notice, and should not be referenced by programs that use SQLite.
       
    17 **
       
    18 ** Some of the definitions that are in this file are marked as
       
    19 ** "experimental".  Experimental interfaces are normally new
       
    20 ** features recently added to SQLite.  We do not anticipate changes
       
    21 ** to experimental interfaces but reserve the right to make minor changes
       
    22 ** if experience from use "in the wild" suggest such changes are prudent.
       
    23 **
       
    24 ** The official C-language API documentation for SQLite is derived
       
    25 ** from comments in this file.  This file is the authoritative source
       
    26 ** on how SQLite interfaces are suppose to operate.
       
    27 **
       
    28 ** The name of this file under configuration management is "sqlite.h.in".
       
    29 ** The makefile makes some minor changes to this file (such as inserting
       
    30 ** the version number) and changes its name to "sqlite3.h" as
       
    31 ** part of the build process.
       
    32 */
       
    33 #ifndef _SQLITE3_H_
       
    34 #define _SQLITE3_H_
       
    35 #include <stdarg.h>     /* Needed for the definition of va_list */
       
    36 
       
    37 /*
       
    38 ** Make sure we can call this stuff from C++.
       
    39 */
       
    40 #ifdef __cplusplus
       
    41 extern "C" {
       
    42 #endif
       
    43 
       
    44 
       
    45 /*
       
    46 ** Add the ability to override 'extern'
       
    47 */
       
    48 #ifndef SQLITE_EXTERN
       
    49 # define SQLITE_EXTERN extern
       
    50 #endif
       
    51 
       
    52 #ifndef SQLITE_API
       
    53 # define SQLITE_API
       
    54 #endif
       
    55 
       
    56 
       
    57 /*
       
    58 ** These no-op macros are used in front of interfaces to mark those
       
    59 ** interfaces as either deprecated or experimental.  New applications
       
    60 ** should not use deprecated interfaces - they are support for backwards
       
    61 ** compatibility only.  Application writers should be aware that
       
    62 ** experimental interfaces are subject to change in point releases.
       
    63 **
       
    64 ** These macros used to resolve to various kinds of compiler magic that
       
    65 ** would generate warning messages when they were used.  But that
       
    66 ** compiler magic ended up generating such a flurry of bug reports
       
    67 ** that we have taken it all out and gone back to using simple
       
    68 ** noop macros.
       
    69 */
       
    70 #define SQLITE_DEPRECATED
       
    71 #define SQLITE_EXPERIMENTAL
       
    72 
       
    73 /*
       
    74 ** Ensure these symbols were not defined by some previous header file.
       
    75 */
       
    76 #ifdef SQLITE_VERSION
       
    77 # undef SQLITE_VERSION
       
    78 #endif
       
    79 #ifdef SQLITE_VERSION_NUMBER
       
    80 # undef SQLITE_VERSION_NUMBER
       
    81 #endif
       
    82 
       
    83 /*
       
    84 ** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100>
       
    85 **
       
    86 ** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
       
    87 ** the sqlite3.h file specify the version of SQLite with which
       
    88 ** that header file is associated.
       
    89 **
       
    90 ** The "version" of SQLite is a string of the form "W.X.Y" or "W.X.Y.Z".
       
    91 ** The W value is major version number and is always 3 in SQLite3.
       
    92 ** The W value only changes when backwards compatibility is
       
    93 ** broken and we intend to never break backwards compatibility.
       
    94 ** The X value is the minor version number and only changes when
       
    95 ** there are major feature enhancements that are forwards compatible
       
    96 ** but not backwards compatible.
       
    97 ** The Y value is the release number and is incremented with
       
    98 ** each release but resets back to 0 whenever X is incremented.
       
    99 ** The Z value only appears on branch releases.
       
   100 **
       
   101 ** The SQLITE_VERSION_NUMBER is an integer that is computed as
       
   102 ** follows:
       
   103 **
       
   104 ** <blockquote><pre>
       
   105 ** SQLITE_VERSION_NUMBER = W*1000000 + X*1000 + Y
       
   106 ** </pre></blockquote>
       
   107 **
       
   108 ** Since version 3.6.18, SQLite source code has been stored in the
       
   109 ** <a href="http://www.fossil-scm.org/">fossil configuration management
       
   110 ** system</a>.  The SQLITE_SOURCE_ID
       
   111 ** macro is a string which identifies a particular check-in of SQLite
       
   112 ** within its configuration management system.  The string contains the
       
   113 ** date and time of the check-in (UTC) and an SHA1 hash of the entire
       
   114 ** source tree.
       
   115 **
       
   116 ** See also: [sqlite3_libversion()],
       
   117 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
       
   118 ** [sqlite_version()] and [sqlite_source_id()].
       
   119 **
       
   120 ** Requirements: [H10011] [H10014]
       
   121 */
       
   122 #define SQLITE_VERSION        "3.6.19"
       
   123 #define SQLITE_VERSION_NUMBER 3006019
       
   124 #define SQLITE_SOURCE_ID      "2009-10-14 11:33:55 c1d499afc50d54b376945b4efb65c56c787a073d"
       
   125 
       
   126 /*
       
   127 ** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
       
   128 ** KEYWORDS: sqlite3_version
       
   129 **
       
   130 ** These interfaces provide the same information as the [SQLITE_VERSION],
       
   131 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] #defines in the header,
       
   132 ** but are associated with the library instead of the header file.  Cautious
       
   133 ** programmers might include assert() statements in their application to
       
   134 ** verify that values returned by these interfaces match the macros in
       
   135 ** the header, and thus insure that the application is
       
   136 ** compiled with matching library and header files.
       
   137 **
       
   138 ** <blockquote><pre>
       
   139 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
       
   140 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
       
   141 ** assert( strcmp(sqlite3_libversion,SQLITE_VERSION)==0 );
       
   142 ** </pre></blockquote>
       
   143 **
       
   144 ** The sqlite3_libversion() function returns the same information as is
       
   145 ** in the sqlite3_version[] string constant.  The function is provided
       
   146 ** for use in DLLs since DLL users usually do not have direct access to string
       
   147 ** constants within the DLL.  Similarly, the sqlite3_sourceid() function
       
   148 ** returns the same information as is in the [SQLITE_SOURCE_ID] #define of
       
   149 ** the header file.
       
   150 **
       
   151 ** See also: [sqlite_version()] and [sqlite_source_id()].
       
   152 **
       
   153 ** Requirements: [H10021] [H10022] [H10023]
       
   154 */
       
   155 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
       
   156 SQLITE_API const char *sqlite3_libversion(void);
       
   157 SQLITE_API const char *sqlite3_sourceid(void);
       
   158 SQLITE_API int sqlite3_libversion_number(void);
       
   159 
       
   160 /*
       
   161 ** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100>
       
   162 **
       
   163 ** SQLite can be compiled with or without mutexes.  When
       
   164 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
       
   165 ** are enabled and SQLite is threadsafe.  When the
       
   166 ** [SQLITE_THREADSAFE] macro is 0, 
       
   167 ** the mutexes are omitted.  Without the mutexes, it is not safe
       
   168 ** to use SQLite concurrently from more than one thread.
       
   169 **
       
   170 ** Enabling mutexes incurs a measurable performance penalty.
       
   171 ** So if speed is of utmost importance, it makes sense to disable
       
   172 ** the mutexes.  But for maximum safety, mutexes should be enabled.
       
   173 ** The default behavior is for mutexes to be enabled.
       
   174 **
       
   175 ** This interface can be used by an application to make sure that the
       
   176 ** version of SQLite that it is linking against was compiled with
       
   177 ** the desired setting of the [SQLITE_THREADSAFE] macro.
       
   178 **
       
   179 ** This interface only reports on the compile-time mutex setting
       
   180 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
       
   181 ** SQLITE_THREADSAFE=1 then mutexes are enabled by default but
       
   182 ** can be fully or partially disabled using a call to [sqlite3_config()]
       
   183 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
       
   184 ** or [SQLITE_CONFIG_MUTEX].  The return value of this function shows
       
   185 ** only the default compile-time setting, not any run-time changes
       
   186 ** to that setting.
       
   187 **
       
   188 ** See the [threading mode] documentation for additional information.
       
   189 **
       
   190 ** Requirements: [H10101] [H10102]
       
   191 */
       
   192 SQLITE_API int sqlite3_threadsafe(void);
       
   193 
       
   194 /*
       
   195 ** CAPI3REF: Database Connection Handle {H12000} <S40200>
       
   196 ** KEYWORDS: {database connection} {database connections}
       
   197 **
       
   198 ** Each open SQLite database is represented by a pointer to an instance of
       
   199 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
       
   200 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
       
   201 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
       
   202 ** is its destructor.  There are many other interfaces (such as
       
   203 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
       
   204 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
       
   205 ** sqlite3 object.
       
   206 */
       
   207 typedef struct sqlite3 sqlite3;
       
   208 
       
   209 /*
       
   210 ** CAPI3REF: 64-Bit Integer Types {H10200} <S10110>
       
   211 ** KEYWORDS: sqlite_int64 sqlite_uint64
       
   212 **
       
   213 ** Because there is no cross-platform way to specify 64-bit integer types
       
   214 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
       
   215 **
       
   216 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
       
   217 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
       
   218 ** compatibility only.
       
   219 **
       
   220 ** Requirements: [H10201] [H10202]
       
   221 */
       
   222 #ifdef SQLITE_INT64_TYPE
       
   223   typedef SQLITE_INT64_TYPE sqlite_int64;
       
   224   typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
       
   225 #elif defined(_MSC_VER) || defined(__BORLANDC__)
       
   226   typedef __int64 sqlite_int64;
       
   227   typedef unsigned __int64 sqlite_uint64;
       
   228 #else
       
   229   typedef long long int sqlite_int64;
       
   230   typedef unsigned long long int sqlite_uint64;
       
   231 #endif
       
   232 typedef sqlite_int64 sqlite3_int64;
       
   233 typedef sqlite_uint64 sqlite3_uint64;
       
   234 
       
   235 /*
       
   236 ** If compiling for a processor that lacks floating point support,
       
   237 ** substitute integer for floating-point.
       
   238 */
       
   239 #ifdef SQLITE_OMIT_FLOATING_POINT
       
   240 # define double sqlite3_int64
       
   241 #endif
       
   242 
       
   243 /*
       
   244 ** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200>
       
   245 **
       
   246 ** This routine is the destructor for the [sqlite3] object.
       
   247 **
       
   248 ** Applications should [sqlite3_finalize | finalize] all [prepared statements]
       
   249 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
       
   250 ** the [sqlite3] object prior to attempting to close the object.
       
   251 ** The [sqlite3_next_stmt()] interface can be used to locate all
       
   252 ** [prepared statements] associated with a [database connection] if desired.
       
   253 ** Typical code might look like this:
       
   254 **
       
   255 ** <blockquote><pre>
       
   256 ** sqlite3_stmt *pStmt;
       
   257 ** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){
       
   258 ** &nbsp;   sqlite3_finalize(pStmt);
       
   259 ** }
       
   260 ** </pre></blockquote>
       
   261 **
       
   262 ** If [sqlite3_close()] is invoked while a transaction is open,
       
   263 ** the transaction is automatically rolled back.
       
   264 **
       
   265 ** The C parameter to [sqlite3_close(C)] must be either a NULL
       
   266 ** pointer or an [sqlite3] object pointer obtained
       
   267 ** from [sqlite3_open()], [sqlite3_open16()], or
       
   268 ** [sqlite3_open_v2()], and not previously closed.
       
   269 **
       
   270 ** Requirements:
       
   271 ** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019]
       
   272 */
       
   273 SQLITE_API int sqlite3_close(sqlite3 *);
       
   274 
       
   275 /*
       
   276 ** The type for a callback function.
       
   277 ** This is legacy and deprecated.  It is included for historical
       
   278 ** compatibility and is not documented.
       
   279 */
       
   280 typedef int (*sqlite3_callback)(void*,int,char**, char**);
       
   281 
       
   282 /*
       
   283 ** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000>
       
   284 **
       
   285 ** The sqlite3_exec() interface is a convenient way of running one or more
       
   286 ** SQL statements without having to write a lot of C code.  The UTF-8 encoded
       
   287 ** SQL statements are passed in as the second parameter to sqlite3_exec().
       
   288 ** The statements are evaluated one by one until either an error or
       
   289 ** an interrupt is encountered, or until they are all done.  The 3rd parameter
       
   290 ** is an optional callback that is invoked once for each row of any query
       
   291 ** results produced by the SQL statements.  The 5th parameter tells where
       
   292 ** to write any error messages.
       
   293 **
       
   294 ** The error message passed back through the 5th parameter is held
       
   295 ** in memory obtained from [sqlite3_malloc()].  To avoid a memory leak,
       
   296 ** the calling application should call [sqlite3_free()] on any error
       
   297 ** message returned through the 5th parameter when it has finished using
       
   298 ** the error message.
       
   299 **
       
   300 ** If the SQL statement in the 2nd parameter is NULL or an empty string
       
   301 ** or a string containing only whitespace and comments, then no SQL
       
   302 ** statements are evaluated and the database is not changed.
       
   303 **
       
   304 ** The sqlite3_exec() interface is implemented in terms of
       
   305 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
       
   306 ** The sqlite3_exec() routine does nothing to the database that cannot be done
       
   307 ** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
       
   308 **
       
   309 ** The first parameter to [sqlite3_exec()] must be an valid and open
       
   310 ** [database connection].
       
   311 **
       
   312 ** The database connection must not be closed while
       
   313 ** [sqlite3_exec()] is running.
       
   314 **
       
   315 ** The calling function should use [sqlite3_free()] to free
       
   316 ** the memory that *errmsg is left pointing at once the error
       
   317 ** message is no longer needed.
       
   318 **
       
   319 ** The SQL statement text in the 2nd parameter to [sqlite3_exec()]
       
   320 ** must remain unchanged while [sqlite3_exec()] is running.
       
   321 **
       
   322 ** Requirements:
       
   323 ** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116]
       
   324 ** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138]
       
   325 */
       
   326 SQLITE_API int sqlite3_exec(
       
   327   sqlite3*,                                  /* An open database */
       
   328   const char *sql,                           /* SQL to be evaluated */
       
   329   int (*callback)(void*,int,char**,char**),  /* Callback function */
       
   330   void *,                                    /* 1st argument to callback */
       
   331   char **errmsg                              /* Error msg written here */
       
   332 );
       
   333 
       
   334 /*
       
   335 ** CAPI3REF: Result Codes {H10210} <S10700>
       
   336 ** KEYWORDS: SQLITE_OK {error code} {error codes}
       
   337 ** KEYWORDS: {result code} {result codes}
       
   338 **
       
   339 ** Many SQLite functions return an integer result code from the set shown
       
   340 ** here in order to indicates success or failure.
       
   341 **
       
   342 ** New error codes may be added in future versions of SQLite.
       
   343 **
       
   344 ** See also: [SQLITE_IOERR_READ | extended result codes]
       
   345 */
       
   346 #define SQLITE_OK           0   /* Successful result */
       
   347 /* beginning-of-error-codes */
       
   348 #define SQLITE_ERROR        1   /* SQL error or missing database */
       
   349 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
       
   350 #define SQLITE_PERM         3   /* Access permission denied */
       
   351 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
       
   352 #define SQLITE_BUSY         5   /* The database file is locked */
       
   353 #define SQLITE_LOCKED       6   /* A table in the database is locked */
       
   354 #define SQLITE_NOMEM        7   /* A malloc() failed */
       
   355 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
       
   356 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
       
   357 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
       
   358 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
       
   359 #define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
       
   360 #define SQLITE_FULL        13   /* Insertion failed because database is full */
       
   361 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
       
   362 #define SQLITE_PROTOCOL    15   /* NOT USED. Database lock protocol error */
       
   363 #define SQLITE_EMPTY       16   /* Database is empty */
       
   364 #define SQLITE_SCHEMA      17   /* The database schema changed */
       
   365 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
       
   366 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
       
   367 #define SQLITE_MISMATCH    20   /* Data type mismatch */
       
   368 #define SQLITE_MISUSE      21   /* Library used incorrectly */
       
   369 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
       
   370 #define SQLITE_AUTH        23   /* Authorization denied */
       
   371 #define SQLITE_FORMAT      24   /* Auxiliary database format error */
       
   372 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
       
   373 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
       
   374 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
       
   375 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
       
   376 /* end-of-error-codes */
       
   377 
       
   378 /*
       
   379 ** CAPI3REF: Extended Result Codes {H10220} <S10700>
       
   380 ** KEYWORDS: {extended error code} {extended error codes}
       
   381 ** KEYWORDS: {extended result code} {extended result codes}
       
   382 **
       
   383 ** In its default configuration, SQLite API routines return one of 26 integer
       
   384 ** [SQLITE_OK | result codes].  However, experience has shown that many of
       
   385 ** these result codes are too coarse-grained.  They do not provide as
       
   386 ** much information about problems as programmers might like.  In an effort to
       
   387 ** address this, newer versions of SQLite (version 3.3.8 and later) include
       
   388 ** support for additional result codes that provide more detailed information
       
   389 ** about errors. The extended result codes are enabled or disabled
       
   390 ** on a per database connection basis using the
       
   391 ** [sqlite3_extended_result_codes()] API.
       
   392 **
       
   393 ** Some of the available extended result codes are listed here.
       
   394 ** One may expect the number of extended result codes will be expand
       
   395 ** over time.  Software that uses extended result codes should expect
       
   396 ** to see new result codes in future releases of SQLite.
       
   397 **
       
   398 ** The SQLITE_OK result code will never be extended.  It will always
       
   399 ** be exactly zero.
       
   400 */
       
   401 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
       
   402 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
       
   403 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
       
   404 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
       
   405 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
       
   406 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
       
   407 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
       
   408 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
       
   409 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
       
   410 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
       
   411 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
       
   412 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
       
   413 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
       
   414 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
       
   415 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
       
   416 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
       
   417 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
       
   418 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED | (1<<8) )
       
   419 
       
   420 /*
       
   421 ** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700>
       
   422 **
       
   423 ** These bit values are intended for use in the
       
   424 ** 3rd parameter to the [sqlite3_open_v2()] interface and
       
   425 ** in the 4th parameter to the xOpen method of the
       
   426 ** [sqlite3_vfs] object.
       
   427 */
       
   428 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
       
   429 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
       
   430 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
       
   431 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
       
   432 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
       
   433 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
       
   434 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
       
   435 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
       
   436 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
       
   437 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
       
   438 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
       
   439 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
       
   440 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
       
   441 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
       
   442 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
       
   443 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
       
   444 
       
   445 /*
       
   446 ** CAPI3REF: Device Characteristics {H10240} <H11120>
       
   447 **
       
   448 ** The xDeviceCapabilities method of the [sqlite3_io_methods]
       
   449 ** object returns an integer which is a vector of the these
       
   450 ** bit values expressing I/O characteristics of the mass storage
       
   451 ** device that holds the file that the [sqlite3_io_methods]
       
   452 ** refers to.
       
   453 **
       
   454 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
       
   455 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
       
   456 ** mean that writes of blocks that are nnn bytes in size and
       
   457 ** are aligned to an address which is an integer multiple of
       
   458 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
       
   459 ** that when data is appended to a file, the data is appended
       
   460 ** first then the size of the file is extended, never the other
       
   461 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
       
   462 ** information is written to disk in the same order as calls
       
   463 ** to xWrite().
       
   464 */
       
   465 #define SQLITE_IOCAP_ATOMIC          0x00000001
       
   466 #define SQLITE_IOCAP_ATOMIC512       0x00000002
       
   467 #define SQLITE_IOCAP_ATOMIC1K        0x00000004
       
   468 #define SQLITE_IOCAP_ATOMIC2K        0x00000008
       
   469 #define SQLITE_IOCAP_ATOMIC4K        0x00000010
       
   470 #define SQLITE_IOCAP_ATOMIC8K        0x00000020
       
   471 #define SQLITE_IOCAP_ATOMIC16K       0x00000040
       
   472 #define SQLITE_IOCAP_ATOMIC32K       0x00000080
       
   473 #define SQLITE_IOCAP_ATOMIC64K       0x00000100
       
   474 #define SQLITE_IOCAP_SAFE_APPEND     0x00000200
       
   475 #define SQLITE_IOCAP_SEQUENTIAL      0x00000400
       
   476 
       
   477 /*
       
   478 ** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310>
       
   479 **
       
   480 ** SQLite uses one of these integer values as the second
       
   481 ** argument to calls it makes to the xLock() and xUnlock() methods
       
   482 ** of an [sqlite3_io_methods] object.
       
   483 */
       
   484 #define SQLITE_LOCK_NONE          0
       
   485 #define SQLITE_LOCK_SHARED        1
       
   486 #define SQLITE_LOCK_RESERVED      2
       
   487 #define SQLITE_LOCK_PENDING       3
       
   488 #define SQLITE_LOCK_EXCLUSIVE     4
       
   489 
       
   490 /*
       
   491 ** CAPI3REF: Synchronization Type Flags {H10260} <H11120>
       
   492 **
       
   493 ** When SQLite invokes the xSync() method of an
       
   494 ** [sqlite3_io_methods] object it uses a combination of
       
   495 ** these integer values as the second argument.
       
   496 **
       
   497 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
       
   498 ** sync operation only needs to flush data to mass storage.  Inode
       
   499 ** information need not be flushed. If the lower four bits of the flag
       
   500 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
       
   501 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
       
   502 ** to use Mac OS X style fullsync instead of fsync().
       
   503 */
       
   504 #define SQLITE_SYNC_NORMAL        0x00002
       
   505 #define SQLITE_SYNC_FULL          0x00003
       
   506 #define SQLITE_SYNC_DATAONLY      0x00010
       
   507 
       
   508 /*
       
   509 ** CAPI3REF: OS Interface Open File Handle {H11110} <S20110>
       
   510 **
       
   511 ** An [sqlite3_file] object represents an open file in the 
       
   512 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
       
   513 ** implementations will
       
   514 ** want to subclass this object by appending additional fields
       
   515 ** for their own use.  The pMethods entry is a pointer to an
       
   516 ** [sqlite3_io_methods] object that defines methods for performing
       
   517 ** I/O operations on the open file.
       
   518 */
       
   519 typedef struct sqlite3_file sqlite3_file;
       
   520 struct sqlite3_file {
       
   521   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
       
   522 };
       
   523 
       
   524 /*
       
   525 ** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110>
       
   526 **
       
   527 ** Every file opened by the [sqlite3_vfs] xOpen method populates an
       
   528 ** [sqlite3_file] object (or, more commonly, a subclass of the
       
   529 ** [sqlite3_file] object) with a pointer to an instance of this object.
       
   530 ** This object defines the methods used to perform various operations
       
   531 ** against the open file represented by the [sqlite3_file] object.
       
   532 **
       
   533 ** If the xOpen method sets the sqlite3_file.pMethods element 
       
   534 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
       
   535 ** may be invoked even if the xOpen reported that it failed.  The
       
   536 ** only way to prevent a call to xClose following a failed xOpen
       
   537 ** is for the xOpen to set the sqlite3_file.pMethods element to NULL.
       
   538 **
       
   539 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
       
   540 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
       
   541 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
       
   542 ** flag may be ORed in to indicate that only the data of the file
       
   543 ** and not its inode needs to be synced.
       
   544 **
       
   545 ** The integer values to xLock() and xUnlock() are one of
       
   546 ** <ul>
       
   547 ** <li> [SQLITE_LOCK_NONE],
       
   548 ** <li> [SQLITE_LOCK_SHARED],
       
   549 ** <li> [SQLITE_LOCK_RESERVED],
       
   550 ** <li> [SQLITE_LOCK_PENDING], or
       
   551 ** <li> [SQLITE_LOCK_EXCLUSIVE].
       
   552 ** </ul>
       
   553 ** xLock() increases the lock. xUnlock() decreases the lock.
       
   554 ** The xCheckReservedLock() method checks whether any database connection,
       
   555 ** either in this process or in some other process, is holding a RESERVED,
       
   556 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
       
   557 ** if such a lock exists and false otherwise.
       
   558 **
       
   559 ** The xFileControl() method is a generic interface that allows custom
       
   560 ** VFS implementations to directly control an open file using the
       
   561 ** [sqlite3_file_control()] interface.  The second "op" argument is an
       
   562 ** integer opcode.  The third argument is a generic pointer intended to
       
   563 ** point to a structure that may contain arguments or space in which to
       
   564 ** write return values.  Potential uses for xFileControl() might be
       
   565 ** functions to enable blocking locks with timeouts, to change the
       
   566 ** locking strategy (for example to use dot-file locks), to inquire
       
   567 ** about the status of a lock, or to break stale locks.  The SQLite
       
   568 ** core reserves all opcodes less than 100 for its own use.
       
   569 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
       
   570 ** Applications that define a custom xFileControl method should use opcodes
       
   571 ** greater than 100 to avoid conflicts.
       
   572 **
       
   573 ** The xSectorSize() method returns the sector size of the
       
   574 ** device that underlies the file.  The sector size is the
       
   575 ** minimum write that can be performed without disturbing
       
   576 ** other bytes in the file.  The xDeviceCharacteristics()
       
   577 ** method returns a bit vector describing behaviors of the
       
   578 ** underlying device:
       
   579 **
       
   580 ** <ul>
       
   581 ** <li> [SQLITE_IOCAP_ATOMIC]
       
   582 ** <li> [SQLITE_IOCAP_ATOMIC512]
       
   583 ** <li> [SQLITE_IOCAP_ATOMIC1K]
       
   584 ** <li> [SQLITE_IOCAP_ATOMIC2K]
       
   585 ** <li> [SQLITE_IOCAP_ATOMIC4K]
       
   586 ** <li> [SQLITE_IOCAP_ATOMIC8K]
       
   587 ** <li> [SQLITE_IOCAP_ATOMIC16K]
       
   588 ** <li> [SQLITE_IOCAP_ATOMIC32K]
       
   589 ** <li> [SQLITE_IOCAP_ATOMIC64K]
       
   590 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
       
   591 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
       
   592 ** </ul>
       
   593 **
       
   594 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
       
   595 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
       
   596 ** mean that writes of blocks that are nnn bytes in size and
       
   597 ** are aligned to an address which is an integer multiple of
       
   598 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
       
   599 ** that when data is appended to a file, the data is appended
       
   600 ** first then the size of the file is extended, never the other
       
   601 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
       
   602 ** information is written to disk in the same order as calls
       
   603 ** to xWrite().
       
   604 **
       
   605 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
       
   606 ** in the unread portions of the buffer with zeros.  A VFS that
       
   607 ** fails to zero-fill short reads might seem to work.  However,
       
   608 ** failure to zero-fill short reads will eventually lead to
       
   609 ** database corruption.
       
   610 */
       
   611 typedef struct sqlite3_io_methods sqlite3_io_methods;
       
   612 struct sqlite3_io_methods {
       
   613   int iVersion;
       
   614   int (*xClose)(sqlite3_file*);
       
   615   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
       
   616   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
       
   617   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
       
   618   int (*xSync)(sqlite3_file*, int flags);
       
   619   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
       
   620   int (*xLock)(sqlite3_file*, int);
       
   621   int (*xUnlock)(sqlite3_file*, int);
       
   622   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
       
   623   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
       
   624   int (*xSectorSize)(sqlite3_file*);
       
   625   int (*xDeviceCharacteristics)(sqlite3_file*);
       
   626   /* Additional methods may be added in future releases */
       
   627 };
       
   628 
       
   629 /*
       
   630 ** CAPI3REF: Standard File Control Opcodes {H11310} <S30800>
       
   631 **
       
   632 ** These integer constants are opcodes for the xFileControl method
       
   633 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
       
   634 ** interface.
       
   635 **
       
   636 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
       
   637 ** opcode causes the xFileControl method to write the current state of
       
   638 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
       
   639 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
       
   640 ** into an integer that the pArg argument points to. This capability
       
   641 ** is used during testing and only needs to be supported when SQLITE_TEST
       
   642 ** is defined.
       
   643 */
       
   644 #define SQLITE_FCNTL_LOCKSTATE        1
       
   645 #define SQLITE_GET_LOCKPROXYFILE      2
       
   646 #define SQLITE_SET_LOCKPROXYFILE      3
       
   647 #define SQLITE_LAST_ERRNO             4
       
   648 
       
   649 /*
       
   650 ** CAPI3REF: Mutex Handle {H17110} <S20130>
       
   651 **
       
   652 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
       
   653 ** abstract type for a mutex object.  The SQLite core never looks
       
   654 ** at the internal representation of an [sqlite3_mutex].  It only
       
   655 ** deals with pointers to the [sqlite3_mutex] object.
       
   656 **
       
   657 ** Mutexes are created using [sqlite3_mutex_alloc()].
       
   658 */
       
   659 typedef struct sqlite3_mutex sqlite3_mutex;
       
   660 
       
   661 /*
       
   662 ** CAPI3REF: OS Interface Object {H11140} <S20100>
       
   663 **
       
   664 ** An instance of the sqlite3_vfs object defines the interface between
       
   665 ** the SQLite core and the underlying operating system.  The "vfs"
       
   666 ** in the name of the object stands for "virtual file system".
       
   667 **
       
   668 ** The value of the iVersion field is initially 1 but may be larger in
       
   669 ** future versions of SQLite.  Additional fields may be appended to this
       
   670 ** object when the iVersion value is increased.  Note that the structure
       
   671 ** of the sqlite3_vfs object changes in the transaction between
       
   672 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
       
   673 ** modified.
       
   674 **
       
   675 ** The szOsFile field is the size of the subclassed [sqlite3_file]
       
   676 ** structure used by this VFS.  mxPathname is the maximum length of
       
   677 ** a pathname in this VFS.
       
   678 **
       
   679 ** Registered sqlite3_vfs objects are kept on a linked list formed by
       
   680 ** the pNext pointer.  The [sqlite3_vfs_register()]
       
   681 ** and [sqlite3_vfs_unregister()] interfaces manage this list
       
   682 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
       
   683 ** searches the list.  Neither the application code nor the VFS
       
   684 ** implementation should use the pNext pointer.
       
   685 **
       
   686 ** The pNext field is the only field in the sqlite3_vfs
       
   687 ** structure that SQLite will ever modify.  SQLite will only access
       
   688 ** or modify this field while holding a particular static mutex.
       
   689 ** The application should never modify anything within the sqlite3_vfs
       
   690 ** object once the object has been registered.
       
   691 **
       
   692 ** The zName field holds the name of the VFS module.  The name must
       
   693 ** be unique across all VFS modules.
       
   694 **
       
   695 ** SQLite will guarantee that the zFilename parameter to xOpen
       
   696 ** is either a NULL pointer or string obtained
       
   697 ** from xFullPathname().  SQLite further guarantees that
       
   698 ** the string will be valid and unchanged until xClose() is
       
   699 ** called. Because of the previous sentence,
       
   700 ** the [sqlite3_file] can safely store a pointer to the
       
   701 ** filename if it needs to remember the filename for some reason.
       
   702 ** If the zFilename parameter is xOpen is a NULL pointer then xOpen
       
   703 ** must invent its own temporary name for the file.  Whenever the 
       
   704 ** xFilename parameter is NULL it will also be the case that the
       
   705 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
       
   706 **
       
   707 ** The flags argument to xOpen() includes all bits set in
       
   708 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
       
   709 ** or [sqlite3_open16()] is used, then flags includes at least
       
   710 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 
       
   711 ** If xOpen() opens a file read-only then it sets *pOutFlags to
       
   712 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
       
   713 **
       
   714 ** SQLite will also add one of the following flags to the xOpen()
       
   715 ** call, depending on the object being opened:
       
   716 **
       
   717 ** <ul>
       
   718 ** <li>  [SQLITE_OPEN_MAIN_DB]
       
   719 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
       
   720 ** <li>  [SQLITE_OPEN_TEMP_DB]
       
   721 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
       
   722 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
       
   723 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
       
   724 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
       
   725 ** </ul>
       
   726 **
       
   727 ** The file I/O implementation can use the object type flags to
       
   728 ** change the way it deals with files.  For example, an application
       
   729 ** that does not care about crash recovery or rollback might make
       
   730 ** the open of a journal file a no-op.  Writes to this journal would
       
   731 ** also be no-ops, and any attempt to read the journal would return
       
   732 ** SQLITE_IOERR.  Or the implementation might recognize that a database
       
   733 ** file will be doing page-aligned sector reads and writes in a random
       
   734 ** order and set up its I/O subsystem accordingly.
       
   735 **
       
   736 ** SQLite might also add one of the following flags to the xOpen method:
       
   737 **
       
   738 ** <ul>
       
   739 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
       
   740 ** <li> [SQLITE_OPEN_EXCLUSIVE]
       
   741 ** </ul>
       
   742 **
       
   743 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
       
   744 ** deleted when it is closed.  The [SQLITE_OPEN_DELETEONCLOSE]
       
   745 ** will be set for TEMP  databases, journals and for subjournals.
       
   746 **
       
   747 ** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
       
   748 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
       
   749 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
       
   750 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 
       
   751 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
       
   752 ** be created, and that it is an error if it already exists.
       
   753 ** It is <i>not</i> used to indicate the file should be opened 
       
   754 ** for exclusive access.
       
   755 **
       
   756 ** At least szOsFile bytes of memory are allocated by SQLite
       
   757 ** to hold the  [sqlite3_file] structure passed as the third
       
   758 ** argument to xOpen.  The xOpen method does not have to
       
   759 ** allocate the structure; it should just fill it in.  Note that
       
   760 ** the xOpen method must set the sqlite3_file.pMethods to either
       
   761 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
       
   762 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
       
   763 ** element will be valid after xOpen returns regardless of the success
       
   764 ** or failure of the xOpen call.
       
   765 **
       
   766 ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
       
   767 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
       
   768 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
       
   769 ** to test whether a file is at least readable.   The file can be a
       
   770 ** directory.
       
   771 **
       
   772 ** SQLite will always allocate at least mxPathname+1 bytes for the
       
   773 ** output buffer xFullPathname.  The exact size of the output buffer
       
   774 ** is also passed as a parameter to both  methods. If the output buffer
       
   775 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
       
   776 ** handled as a fatal error by SQLite, vfs implementations should endeavor
       
   777 ** to prevent this by setting mxPathname to a sufficiently large value.
       
   778 **
       
   779 ** The xRandomness(), xSleep(), and xCurrentTime() interfaces
       
   780 ** are not strictly a part of the filesystem, but they are
       
   781 ** included in the VFS structure for completeness.
       
   782 ** The xRandomness() function attempts to return nBytes bytes
       
   783 ** of good-quality randomness into zOut.  The return value is
       
   784 ** the actual number of bytes of randomness obtained.
       
   785 ** The xSleep() method causes the calling thread to sleep for at
       
   786 ** least the number of microseconds given.  The xCurrentTime()
       
   787 ** method returns a Julian Day Number for the current date and time.
       
   788 **
       
   789 */
       
   790 typedef struct sqlite3_vfs sqlite3_vfs;
       
   791 struct sqlite3_vfs {
       
   792   int iVersion;            /* Structure version number */
       
   793   int szOsFile;            /* Size of subclassed sqlite3_file */
       
   794   int mxPathname;          /* Maximum file pathname length */
       
   795   sqlite3_vfs *pNext;      /* Next registered VFS */
       
   796   const char *zName;       /* Name of this virtual file system */
       
   797   void *pAppData;          /* Pointer to application-specific data */
       
   798   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
       
   799                int flags, int *pOutFlags);
       
   800   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
       
   801   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
       
   802   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
       
   803   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
       
   804   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
       
   805   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
       
   806   void (*xDlClose)(sqlite3_vfs*, void*);
       
   807   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
       
   808   int (*xSleep)(sqlite3_vfs*, int microseconds);
       
   809   int (*xCurrentTime)(sqlite3_vfs*, double*);
       
   810   int (*xGetLastError)(sqlite3_vfs*, int, char *);
       
   811   /* New fields may be appended in figure versions.  The iVersion
       
   812   ** value will increment whenever this happens. */
       
   813 };
       
   814 
       
   815 /*
       
   816 ** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140>
       
   817 **
       
   818 ** These integer constants can be used as the third parameter to
       
   819 ** the xAccess method of an [sqlite3_vfs] object. {END}  They determine
       
   820 ** what kind of permissions the xAccess method is looking for.
       
   821 ** With SQLITE_ACCESS_EXISTS, the xAccess method
       
   822 ** simply checks whether the file exists.
       
   823 ** With SQLITE_ACCESS_READWRITE, the xAccess method
       
   824 ** checks whether the file is both readable and writable.
       
   825 ** With SQLITE_ACCESS_READ, the xAccess method
       
   826 ** checks whether the file is readable.
       
   827 */
       
   828 #define SQLITE_ACCESS_EXISTS    0
       
   829 #define SQLITE_ACCESS_READWRITE 1
       
   830 #define SQLITE_ACCESS_READ      2
       
   831 
       
   832 /*
       
   833 ** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100>
       
   834 **
       
   835 ** The sqlite3_initialize() routine initializes the
       
   836 ** SQLite library.  The sqlite3_shutdown() routine
       
   837 ** deallocates any resources that were allocated by sqlite3_initialize().
       
   838 **
       
   839 ** A call to sqlite3_initialize() is an "effective" call if it is
       
   840 ** the first time sqlite3_initialize() is invoked during the lifetime of
       
   841 ** the process, or if it is the first time sqlite3_initialize() is invoked
       
   842 ** following a call to sqlite3_shutdown().  Only an effective call
       
   843 ** of sqlite3_initialize() does any initialization.  All other calls
       
   844 ** are harmless no-ops.
       
   845 **
       
   846 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
       
   847 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  Only
       
   848 ** an effective call to sqlite3_shutdown() does any deinitialization.
       
   849 ** All other calls to sqlite3_shutdown() are harmless no-ops.
       
   850 **
       
   851 ** Among other things, sqlite3_initialize() shall invoke
       
   852 ** sqlite3_os_init().  Similarly, sqlite3_shutdown()
       
   853 ** shall invoke sqlite3_os_end().
       
   854 **
       
   855 ** The sqlite3_initialize() routine returns [SQLITE_OK] on success.
       
   856 ** If for some reason, sqlite3_initialize() is unable to initialize
       
   857 ** the library (perhaps it is unable to allocate a needed resource such
       
   858 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
       
   859 **
       
   860 ** The sqlite3_initialize() routine is called internally by many other
       
   861 ** SQLite interfaces so that an application usually does not need to
       
   862 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
       
   863 ** calls sqlite3_initialize() so the SQLite library will be automatically
       
   864 ** initialized when [sqlite3_open()] is called if it has not be initialized
       
   865 ** already.  However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
       
   866 ** compile-time option, then the automatic calls to sqlite3_initialize()
       
   867 ** are omitted and the application must call sqlite3_initialize() directly
       
   868 ** prior to using any other SQLite interface.  For maximum portability,
       
   869 ** it is recommended that applications always invoke sqlite3_initialize()
       
   870 ** directly prior to using any other SQLite interface.  Future releases
       
   871 ** of SQLite may require this.  In other words, the behavior exhibited
       
   872 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
       
   873 ** default behavior in some future release of SQLite.
       
   874 **
       
   875 ** The sqlite3_os_init() routine does operating-system specific
       
   876 ** initialization of the SQLite library.  The sqlite3_os_end()
       
   877 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
       
   878 ** performed by these routines include allocation or deallocation
       
   879 ** of static resources, initialization of global variables,
       
   880 ** setting up a default [sqlite3_vfs] module, or setting up
       
   881 ** a default configuration using [sqlite3_config()].
       
   882 **
       
   883 ** The application should never invoke either sqlite3_os_init()
       
   884 ** or sqlite3_os_end() directly.  The application should only invoke
       
   885 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
       
   886 ** interface is called automatically by sqlite3_initialize() and
       
   887 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
       
   888 ** implementations for sqlite3_os_init() and sqlite3_os_end()
       
   889 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
       
   890 ** When [custom builds | built for other platforms]
       
   891 ** (using the [SQLITE_OS_OTHER=1] compile-time
       
   892 ** option) the application must supply a suitable implementation for
       
   893 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
       
   894 ** implementation of sqlite3_os_init() or sqlite3_os_end()
       
   895 ** must return [SQLITE_OK] on success and some other [error code] upon
       
   896 ** failure.
       
   897 */
       
   898 SQLITE_API int sqlite3_initialize(void);
       
   899 SQLITE_API int sqlite3_shutdown(void);
       
   900 SQLITE_API int sqlite3_os_init(void);
       
   901 SQLITE_API int sqlite3_os_end(void);
       
   902 
       
   903 /*
       
   904 ** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200>
       
   905 ** EXPERIMENTAL
       
   906 **
       
   907 ** The sqlite3_config() interface is used to make global configuration
       
   908 ** changes to SQLite in order to tune SQLite to the specific needs of
       
   909 ** the application.  The default configuration is recommended for most
       
   910 ** applications and so this routine is usually not necessary.  It is
       
   911 ** provided to support rare applications with unusual needs.
       
   912 **
       
   913 ** The sqlite3_config() interface is not threadsafe.  The application
       
   914 ** must insure that no other SQLite interfaces are invoked by other
       
   915 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
       
   916 ** may only be invoked prior to library initialization using
       
   917 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
       
   918 ** Note, however, that sqlite3_config() can be called as part of the
       
   919 ** implementation of an application-defined [sqlite3_os_init()].
       
   920 **
       
   921 ** The first argument to sqlite3_config() is an integer
       
   922 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
       
   923 ** what property of SQLite is to be configured.  Subsequent arguments
       
   924 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
       
   925 ** in the first argument.
       
   926 **
       
   927 ** When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
       
   928 ** If the option is unknown or SQLite is unable to set the option
       
   929 ** then this routine returns a non-zero [error code].
       
   930 **
       
   931 ** Requirements:
       
   932 ** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135]
       
   933 ** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159]
       
   934 ** [H14162] [H14165] [H14168]
       
   935 */
       
   936 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_config(int, ...);
       
   937 
       
   938 /*
       
   939 ** CAPI3REF: Configure database connections  {H14200} <S20000>
       
   940 ** EXPERIMENTAL
       
   941 **
       
   942 ** The sqlite3_db_config() interface is used to make configuration
       
   943 ** changes to a [database connection].  The interface is similar to
       
   944 ** [sqlite3_config()] except that the changes apply to a single
       
   945 ** [database connection] (specified in the first argument).  The
       
   946 ** sqlite3_db_config() interface can only be used immediately after
       
   947 ** the database connection is created using [sqlite3_open()],
       
   948 ** [sqlite3_open16()], or [sqlite3_open_v2()].  
       
   949 **
       
   950 ** The second argument to sqlite3_db_config(D,V,...)  is the
       
   951 ** configuration verb - an integer code that indicates what
       
   952 ** aspect of the [database connection] is being configured.
       
   953 ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE].
       
   954 ** New verbs are likely to be added in future releases of SQLite.
       
   955 ** Additional arguments depend on the verb.
       
   956 **
       
   957 ** Requirements:
       
   958 ** [H14203] [H14206] [H14209] [H14212] [H14215]
       
   959 */
       
   960 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
       
   961 
       
   962 /*
       
   963 ** CAPI3REF: Memory Allocation Routines {H10155} <S20120>
       
   964 ** EXPERIMENTAL
       
   965 **
       
   966 ** An instance of this object defines the interface between SQLite
       
   967 ** and low-level memory allocation routines.
       
   968 **
       
   969 ** This object is used in only one place in the SQLite interface.
       
   970 ** A pointer to an instance of this object is the argument to
       
   971 ** [sqlite3_config()] when the configuration option is
       
   972 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].  
       
   973 ** By creating an instance of this object
       
   974 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
       
   975 ** during configuration, an application can specify an alternative
       
   976 ** memory allocation subsystem for SQLite to use for all of its
       
   977 ** dynamic memory needs.
       
   978 **
       
   979 ** Note that SQLite comes with several [built-in memory allocators]
       
   980 ** that are perfectly adequate for the overwhelming majority of applications
       
   981 ** and that this object is only useful to a tiny minority of applications
       
   982 ** with specialized memory allocation requirements.  This object is
       
   983 ** also used during testing of SQLite in order to specify an alternative
       
   984 ** memory allocator that simulates memory out-of-memory conditions in
       
   985 ** order to verify that SQLite recovers gracefully from such
       
   986 ** conditions.
       
   987 **
       
   988 ** The xMalloc and xFree methods must work like the
       
   989 ** malloc() and free() functions from the standard C library.
       
   990 ** The xRealloc method must work like realloc() from the standard C library
       
   991 ** with the exception that if the second argument to xRealloc is zero,
       
   992 ** xRealloc must be a no-op - it must not perform any allocation or
       
   993 ** deallocation.  SQLite guaranteeds that the second argument to
       
   994 ** xRealloc is always a value returned by a prior call to xRoundup.
       
   995 ** And so in cases where xRoundup always returns a positive number,
       
   996 ** xRealloc can perform exactly as the standard library realloc() and
       
   997 ** still be in compliance with this specification.
       
   998 **
       
   999 ** xSize should return the allocated size of a memory allocation
       
  1000 ** previously obtained from xMalloc or xRealloc.  The allocated size
       
  1001 ** is always at least as big as the requested size but may be larger.
       
  1002 **
       
  1003 ** The xRoundup method returns what would be the allocated size of
       
  1004 ** a memory allocation given a particular requested size.  Most memory
       
  1005 ** allocators round up memory allocations at least to the next multiple
       
  1006 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
       
  1007 ** Every memory allocation request coming in through [sqlite3_malloc()]
       
  1008 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0, 
       
  1009 ** that causes the corresponding memory allocation to fail.
       
  1010 **
       
  1011 ** The xInit method initializes the memory allocator.  (For example,
       
  1012 ** it might allocate any require mutexes or initialize internal data
       
  1013 ** structures.  The xShutdown method is invoked (indirectly) by
       
  1014 ** [sqlite3_shutdown()] and should deallocate any resources acquired
       
  1015 ** by xInit.  The pAppData pointer is used as the only parameter to
       
  1016 ** xInit and xShutdown.
       
  1017 **
       
  1018 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
       
  1019 ** the xInit method, so the xInit method need not be threadsafe.  The
       
  1020 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
       
  1021 ** not need to be threadsafe either.  For all other methods, SQLite
       
  1022 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
       
  1023 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
       
  1024 ** it is by default) and so the methods are automatically serialized.
       
  1025 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
       
  1026 ** methods must be threadsafe or else make their own arrangements for
       
  1027 ** serialization.
       
  1028 **
       
  1029 ** SQLite will never invoke xInit() more than once without an intervening
       
  1030 ** call to xShutdown().
       
  1031 */
       
  1032 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
       
  1033 struct sqlite3_mem_methods {
       
  1034   void *(*xMalloc)(int);         /* Memory allocation function */
       
  1035   void (*xFree)(void*);          /* Free a prior allocation */
       
  1036   void *(*xRealloc)(void*,int);  /* Resize an allocation */
       
  1037   int (*xSize)(void*);           /* Return the size of an allocation */
       
  1038   int (*xRoundup)(int);          /* Round up request size to allocation size */
       
  1039   int (*xInit)(void*);           /* Initialize the memory allocator */
       
  1040   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
       
  1041   void *pAppData;                /* Argument to xInit() and xShutdown() */
       
  1042 };
       
  1043 
       
  1044 /*
       
  1045 ** CAPI3REF: Configuration Options {H10160} <S20000>
       
  1046 ** EXPERIMENTAL
       
  1047 **
       
  1048 ** These constants are the available integer configuration options that
       
  1049 ** can be passed as the first argument to the [sqlite3_config()] interface.
       
  1050 **
       
  1051 ** New configuration options may be added in future releases of SQLite.
       
  1052 ** Existing configuration options might be discontinued.  Applications
       
  1053 ** should check the return code from [sqlite3_config()] to make sure that
       
  1054 ** the call worked.  The [sqlite3_config()] interface will return a
       
  1055 ** non-zero [error code] if a discontinued or unsupported configuration option
       
  1056 ** is invoked.
       
  1057 **
       
  1058 ** <dl>
       
  1059 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
       
  1060 ** <dd>There are no arguments to this option.  This option disables
       
  1061 ** all mutexing and puts SQLite into a mode where it can only be used
       
  1062 ** by a single thread.</dd>
       
  1063 **
       
  1064 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
       
  1065 ** <dd>There are no arguments to this option.  This option disables
       
  1066 ** mutexing on [database connection] and [prepared statement] objects.
       
  1067 ** The application is responsible for serializing access to
       
  1068 ** [database connections] and [prepared statements].  But other mutexes
       
  1069 ** are enabled so that SQLite will be safe to use in a multi-threaded
       
  1070 ** environment as long as no two threads attempt to use the same
       
  1071 ** [database connection] at the same time.  See the [threading mode]
       
  1072 ** documentation for additional information.</dd>
       
  1073 **
       
  1074 ** <dt>SQLITE_CONFIG_SERIALIZED</dt>
       
  1075 ** <dd>There are no arguments to this option.  This option enables
       
  1076 ** all mutexes including the recursive
       
  1077 ** mutexes on [database connection] and [prepared statement] objects.
       
  1078 ** In this mode (which is the default when SQLite is compiled with
       
  1079 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
       
  1080 ** to [database connections] and [prepared statements] so that the
       
  1081 ** application is free to use the same [database connection] or the
       
  1082 ** same [prepared statement] in different threads at the same time.
       
  1083 ** See the [threading mode] documentation for additional information.</dd>
       
  1084 **
       
  1085 ** <dt>SQLITE_CONFIG_MALLOC</dt>
       
  1086 ** <dd>This option takes a single argument which is a pointer to an
       
  1087 ** instance of the [sqlite3_mem_methods] structure.  The argument specifies
       
  1088 ** alternative low-level memory allocation routines to be used in place of
       
  1089 ** the memory allocation routines built into SQLite.</dd>
       
  1090 **
       
  1091 ** <dt>SQLITE_CONFIG_GETMALLOC</dt>
       
  1092 ** <dd>This option takes a single argument which is a pointer to an
       
  1093 ** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
       
  1094 ** structure is filled with the currently defined memory allocation routines.
       
  1095 ** This option can be used to overload the default memory allocation
       
  1096 ** routines with a wrapper that simulations memory allocation failure or
       
  1097 ** tracks memory usage, for example.</dd>
       
  1098 **
       
  1099 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
       
  1100 ** <dd>This option takes single argument of type int, interpreted as a 
       
  1101 ** boolean, which enables or disables the collection of memory allocation 
       
  1102 ** statistics. When disabled, the following SQLite interfaces become 
       
  1103 ** non-operational:
       
  1104 **   <ul>
       
  1105 **   <li> [sqlite3_memory_used()]
       
  1106 **   <li> [sqlite3_memory_highwater()]
       
  1107 **   <li> [sqlite3_soft_heap_limit()]
       
  1108 **   <li> [sqlite3_status()]
       
  1109 **   </ul>
       
  1110 ** </dd>
       
  1111 **
       
  1112 ** <dt>SQLITE_CONFIG_SCRATCH</dt>
       
  1113 ** <dd>This option specifies a static memory buffer that SQLite can use for
       
  1114 ** scratch memory.  There are three arguments:  A pointer an 8-byte
       
  1115 ** aligned memory buffer from which the scrach allocations will be
       
  1116 ** drawn, the size of each scratch allocation (sz),
       
  1117 ** and the maximum number of scratch allocations (N).  The sz
       
  1118 ** argument must be a multiple of 16. The sz parameter should be a few bytes
       
  1119 ** larger than the actual scratch space required due to internal overhead.
       
  1120 ** The first argument should pointer to an 8-byte aligned buffer
       
  1121 ** of at least sz*N bytes of memory.
       
  1122 ** SQLite will use no more than one scratch buffer at once per thread, so
       
  1123 ** N should be set to the expected maximum number of threads.  The sz
       
  1124 ** parameter should be 6 times the size of the largest database page size.
       
  1125 ** Scratch buffers are used as part of the btree balance operation.  If
       
  1126 ** The btree balancer needs additional memory beyond what is provided by
       
  1127 ** scratch buffers or if no scratch buffer space is specified, then SQLite
       
  1128 ** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
       
  1129 **
       
  1130 ** <dt>SQLITE_CONFIG_PAGECACHE</dt>
       
  1131 ** <dd>This option specifies a static memory buffer that SQLite can use for
       
  1132 ** the database page cache with the default page cache implemenation.  
       
  1133 ** This configuration should not be used if an application-define page
       
  1134 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
       
  1135 ** There are three arguments to this option: A pointer to 8-byte aligned
       
  1136 ** memory, the size of each page buffer (sz), and the number of pages (N).
       
  1137 ** The sz argument should be the size of the largest database page
       
  1138 ** (a power of two between 512 and 32768) plus a little extra for each
       
  1139 ** page header.  The page header size is 20 to 40 bytes depending on
       
  1140 ** the host architecture.  It is harmless, apart from the wasted memory,
       
  1141 ** to make sz a little too large.  The first
       
  1142 ** argument should point to an allocation of at least sz*N bytes of memory.
       
  1143 ** SQLite will use the memory provided by the first argument to satisfy its
       
  1144 ** memory needs for the first N pages that it adds to cache.  If additional
       
  1145 ** page cache memory is needed beyond what is provided by this option, then
       
  1146 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
       
  1147 ** The implementation might use one or more of the N buffers to hold 
       
  1148 ** memory accounting information. The pointer in the first argument must
       
  1149 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite
       
  1150 ** will be undefined.</dd>
       
  1151 **
       
  1152 ** <dt>SQLITE_CONFIG_HEAP</dt>
       
  1153 ** <dd>This option specifies a static memory buffer that SQLite will use
       
  1154 ** for all of its dynamic memory allocation needs beyond those provided
       
  1155 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
       
  1156 ** There are three arguments: An 8-byte aligned pointer to the memory,
       
  1157 ** the number of bytes in the memory buffer, and the minimum allocation size.
       
  1158 ** If the first pointer (the memory pointer) is NULL, then SQLite reverts
       
  1159 ** to using its default memory allocator (the system malloc() implementation),
       
  1160 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  If the
       
  1161 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
       
  1162 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
       
  1163 ** allocator is engaged to handle all of SQLites memory allocation needs.
       
  1164 ** The first pointer (the memory pointer) must be aligned to an 8-byte
       
  1165 ** boundary or subsequent behavior of SQLite will be undefined.</dd>
       
  1166 **
       
  1167 ** <dt>SQLITE_CONFIG_MUTEX</dt>
       
  1168 ** <dd>This option takes a single argument which is a pointer to an
       
  1169 ** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
       
  1170 ** alternative low-level mutex routines to be used in place
       
  1171 ** the mutex routines built into SQLite.</dd>
       
  1172 **
       
  1173 ** <dt>SQLITE_CONFIG_GETMUTEX</dt>
       
  1174 ** <dd>This option takes a single argument which is a pointer to an
       
  1175 ** instance of the [sqlite3_mutex_methods] structure.  The
       
  1176 ** [sqlite3_mutex_methods]
       
  1177 ** structure is filled with the currently defined mutex routines.
       
  1178 ** This option can be used to overload the default mutex allocation
       
  1179 ** routines with a wrapper used to track mutex usage for performance
       
  1180 ** profiling or testing, for example.</dd>
       
  1181 **
       
  1182 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
       
  1183 ** <dd>This option takes two arguments that determine the default
       
  1184 ** memory allocation lookaside optimization.  The first argument is the
       
  1185 ** size of each lookaside buffer slot and the second is the number of
       
  1186 ** slots allocated to each database connection.  This option sets the
       
  1187 ** <i>default</i> lookaside size.  The [SQLITE_DBCONFIG_LOOKASIDE]
       
  1188 ** verb to [sqlite3_db_config()] can be used to change the lookaside
       
  1189 ** configuration on individual connections.</dd>
       
  1190 **
       
  1191 ** <dt>SQLITE_CONFIG_PCACHE</dt>
       
  1192 ** <dd>This option takes a single argument which is a pointer to
       
  1193 ** an [sqlite3_pcache_methods] object.  This object specifies the interface
       
  1194 ** to a custom page cache implementation.  SQLite makes a copy of the
       
  1195 ** object and uses it for page cache memory allocations.</dd>
       
  1196 **
       
  1197 ** <dt>SQLITE_CONFIG_GETPCACHE</dt>
       
  1198 ** <dd>This option takes a single argument which is a pointer to an
       
  1199 ** [sqlite3_pcache_methods] object.  SQLite copies of the current
       
  1200 ** page cache implementation into that object.</dd>
       
  1201 **
       
  1202 ** </dl>
       
  1203 */
       
  1204 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
       
  1205 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
       
  1206 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
       
  1207 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
       
  1208 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
       
  1209 #define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
       
  1210 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
       
  1211 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
       
  1212 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
       
  1213 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
       
  1214 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
       
  1215 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
       
  1216 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
       
  1217 #define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
       
  1218 #define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
       
  1219 
       
  1220 /*
       
  1221 ** CAPI3REF: Configuration Options {H10170} <S20000>
       
  1222 ** EXPERIMENTAL
       
  1223 **
       
  1224 ** These constants are the available integer configuration options that
       
  1225 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
       
  1226 **
       
  1227 ** New configuration options may be added in future releases of SQLite.
       
  1228 ** Existing configuration options might be discontinued.  Applications
       
  1229 ** should check the return code from [sqlite3_db_config()] to make sure that
       
  1230 ** the call worked.  The [sqlite3_db_config()] interface will return a
       
  1231 ** non-zero [error code] if a discontinued or unsupported configuration option
       
  1232 ** is invoked.
       
  1233 **
       
  1234 ** <dl>
       
  1235 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
       
  1236 ** <dd>This option takes three additional arguments that determine the 
       
  1237 ** [lookaside memory allocator] configuration for the [database connection].
       
  1238 ** The first argument (the third parameter to [sqlite3_db_config()] is a
       
  1239 ** pointer to an memory buffer to use for lookaside memory.
       
  1240 ** The first argument may be NULL in which case SQLite will allocate the
       
  1241 ** lookaside buffer itself using [sqlite3_malloc()].  The second argument is the
       
  1242 ** size of each lookaside buffer slot and the third argument is the number of
       
  1243 ** slots.  The size of the buffer in the first argument must be greater than
       
  1244 ** or equal to the product of the second and third arguments.  The buffer
       
  1245 ** must be aligned to an 8-byte boundary.  If the second argument is not
       
  1246 ** a multiple of 8, it is internally rounded down to the next smaller
       
  1247 ** multiple of 8.  See also: [SQLITE_CONFIG_LOOKASIDE]</dd>
       
  1248 **
       
  1249 ** </dl>
       
  1250 */
       
  1251 #define SQLITE_DBCONFIG_LOOKASIDE    1001  /* void* int int */
       
  1252 
       
  1253 
       
  1254 /*
       
  1255 ** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
       
  1256 **
       
  1257 ** The sqlite3_extended_result_codes() routine enables or disables the
       
  1258 ** [extended result codes] feature of SQLite. The extended result
       
  1259 ** codes are disabled by default for historical compatibility considerations.
       
  1260 **
       
  1261 ** Requirements:
       
  1262 ** [H12201] [H12202]
       
  1263 */
       
  1264 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
       
  1265 
       
  1266 /*
       
  1267 ** CAPI3REF: Last Insert Rowid {H12220} <S10700>
       
  1268 **
       
  1269 ** Each entry in an SQLite table has a unique 64-bit signed
       
  1270 ** integer key called the [ROWID | "rowid"]. The rowid is always available
       
  1271 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
       
  1272 ** names are not also used by explicitly declared columns. If
       
  1273 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
       
  1274 ** is another alias for the rowid.
       
  1275 **
       
  1276 ** This routine returns the [rowid] of the most recent
       
  1277 ** successful [INSERT] into the database from the [database connection]
       
  1278 ** in the first argument.  If no successful [INSERT]s
       
  1279 ** have ever occurred on that database connection, zero is returned.
       
  1280 **
       
  1281 ** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
       
  1282 ** row is returned by this routine as long as the trigger is running.
       
  1283 ** But once the trigger terminates, the value returned by this routine
       
  1284 ** reverts to the last value inserted before the trigger fired.
       
  1285 **
       
  1286 ** An [INSERT] that fails due to a constraint violation is not a
       
  1287 ** successful [INSERT] and does not change the value returned by this
       
  1288 ** routine.  Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
       
  1289 ** and INSERT OR ABORT make no changes to the return value of this
       
  1290 ** routine when their insertion fails.  When INSERT OR REPLACE
       
  1291 ** encounters a constraint violation, it does not fail.  The
       
  1292 ** INSERT continues to completion after deleting rows that caused
       
  1293 ** the constraint problem so INSERT OR REPLACE will always change
       
  1294 ** the return value of this interface.
       
  1295 **
       
  1296 ** For the purposes of this routine, an [INSERT] is considered to
       
  1297 ** be successful even if it is subsequently rolled back.
       
  1298 **
       
  1299 ** Requirements:
       
  1300 ** [H12221] [H12223]
       
  1301 **
       
  1302 ** If a separate thread performs a new [INSERT] on the same
       
  1303 ** database connection while the [sqlite3_last_insert_rowid()]
       
  1304 ** function is running and thus changes the last insert [rowid],
       
  1305 ** then the value returned by [sqlite3_last_insert_rowid()] is
       
  1306 ** unpredictable and might not equal either the old or the new
       
  1307 ** last insert [rowid].
       
  1308 */
       
  1309 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
       
  1310 
       
  1311 /*
       
  1312 ** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
       
  1313 **
       
  1314 ** This function returns the number of database rows that were changed
       
  1315 ** or inserted or deleted by the most recently completed SQL statement
       
  1316 ** on the [database connection] specified by the first parameter.
       
  1317 ** Only changes that are directly specified by the [INSERT], [UPDATE],
       
  1318 ** or [DELETE] statement are counted.  Auxiliary changes caused by
       
  1319 ** triggers or [foreign key actions] are not counted. Use the
       
  1320 ** [sqlite3_total_changes()] function to find the total number of changes
       
  1321 ** including changes caused by triggers and foreign key actions.
       
  1322 **
       
  1323 ** Changes to a view that are simulated by an [INSTEAD OF trigger]
       
  1324 ** are not counted.  Only real table changes are counted.
       
  1325 **
       
  1326 ** A "row change" is a change to a single row of a single table
       
  1327 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
       
  1328 ** are changed as side effects of [REPLACE] constraint resolution,
       
  1329 ** rollback, ABORT processing, [DROP TABLE], or by any other
       
  1330 ** mechanisms do not count as direct row changes.
       
  1331 **
       
  1332 ** A "trigger context" is a scope of execution that begins and
       
  1333 ** ends with the script of a [CREATE TRIGGER | trigger]. 
       
  1334 ** Most SQL statements are
       
  1335 ** evaluated outside of any trigger.  This is the "top level"
       
  1336 ** trigger context.  If a trigger fires from the top level, a
       
  1337 ** new trigger context is entered for the duration of that one
       
  1338 ** trigger.  Subtriggers create subcontexts for their duration.
       
  1339 **
       
  1340 ** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
       
  1341 ** not create a new trigger context.
       
  1342 **
       
  1343 ** This function returns the number of direct row changes in the
       
  1344 ** most recent INSERT, UPDATE, or DELETE statement within the same
       
  1345 ** trigger context.
       
  1346 **
       
  1347 ** Thus, when called from the top level, this function returns the
       
  1348 ** number of changes in the most recent INSERT, UPDATE, or DELETE
       
  1349 ** that also occurred at the top level.  Within the body of a trigger,
       
  1350 ** the sqlite3_changes() interface can be called to find the number of
       
  1351 ** changes in the most recently completed INSERT, UPDATE, or DELETE
       
  1352 ** statement within the body of the same trigger.
       
  1353 ** However, the number returned does not include changes
       
  1354 ** caused by subtriggers since those have their own context.
       
  1355 **
       
  1356 ** See also the [sqlite3_total_changes()] interface and the
       
  1357 ** [count_changes pragma].
       
  1358 **
       
  1359 ** Requirements:
       
  1360 ** [H12241] [H12243]
       
  1361 **
       
  1362 ** If a separate thread makes changes on the same database connection
       
  1363 ** while [sqlite3_changes()] is running then the value returned
       
  1364 ** is unpredictable and not meaningful.
       
  1365 */
       
  1366 SQLITE_API int sqlite3_changes(sqlite3*);
       
  1367 
       
  1368 /*
       
  1369 ** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
       
  1370 **
       
  1371 ** This function returns the number of row changes caused by [INSERT],
       
  1372 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.
       
  1373 ** The count includes all changes from all [CREATE TRIGGER | trigger] 
       
  1374 ** contexts and changes made by [foreign key actions]. However,
       
  1375 ** the count does not include changes used to implement [REPLACE] constraints,
       
  1376 ** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The
       
  1377 ** count does not include rows of views that fire an [INSTEAD OF trigger],
       
  1378 ** though if the INSTEAD OF trigger makes changes of its own, those changes 
       
  1379 ** are counted.
       
  1380 ** The changes are counted as soon as the statement that makes them is
       
  1381 ** completed (when the statement handle is passed to [sqlite3_reset()] or
       
  1382 ** [sqlite3_finalize()]).
       
  1383 **
       
  1384 ** See also the [sqlite3_changes()] interface and the
       
  1385 ** [count_changes pragma].
       
  1386 **
       
  1387 ** Requirements:
       
  1388 ** [H12261] [H12263]
       
  1389 **
       
  1390 ** If a separate thread makes changes on the same database connection
       
  1391 ** while [sqlite3_total_changes()] is running then the value
       
  1392 ** returned is unpredictable and not meaningful.
       
  1393 */
       
  1394 SQLITE_API int sqlite3_total_changes(sqlite3*);
       
  1395 
       
  1396 /*
       
  1397 ** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500>
       
  1398 **
       
  1399 ** This function causes any pending database operation to abort and
       
  1400 ** return at its earliest opportunity. This routine is typically
       
  1401 ** called in response to a user action such as pressing "Cancel"
       
  1402 ** or Ctrl-C where the user wants a long query operation to halt
       
  1403 ** immediately.
       
  1404 **
       
  1405 ** It is safe to call this routine from a thread different from the
       
  1406 ** thread that is currently running the database operation.  But it
       
  1407 ** is not safe to call this routine with a [database connection] that
       
  1408 ** is closed or might close before sqlite3_interrupt() returns.
       
  1409 **
       
  1410 ** If an SQL operation is very nearly finished at the time when
       
  1411 ** sqlite3_interrupt() is called, then it might not have an opportunity
       
  1412 ** to be interrupted and might continue to completion.
       
  1413 **
       
  1414 ** An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
       
  1415 ** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
       
  1416 ** that is inside an explicit transaction, then the entire transaction
       
  1417 ** will be rolled back automatically.
       
  1418 **
       
  1419 ** The sqlite3_interrupt(D) call is in effect until all currently running
       
  1420 ** SQL statements on [database connection] D complete.  Any new SQL statements
       
  1421 ** that are started after the sqlite3_interrupt() call and before the 
       
  1422 ** running statements reaches zero are interrupted as if they had been
       
  1423 ** running prior to the sqlite3_interrupt() call.  New SQL statements
       
  1424 ** that are started after the running statement count reaches zero are
       
  1425 ** not effected by the sqlite3_interrupt().
       
  1426 ** A call to sqlite3_interrupt(D) that occurs when there are no running
       
  1427 ** SQL statements is a no-op and has no effect on SQL statements
       
  1428 ** that are started after the sqlite3_interrupt() call returns.
       
  1429 **
       
  1430 ** Requirements:
       
  1431 ** [H12271] [H12272]
       
  1432 **
       
  1433 ** If the database connection closes while [sqlite3_interrupt()]
       
  1434 ** is running then bad things will likely happen.
       
  1435 */
       
  1436 SQLITE_API void sqlite3_interrupt(sqlite3*);
       
  1437 
       
  1438 /*
       
  1439 ** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200>
       
  1440 **
       
  1441 ** These routines are useful during command-line input to determine if the
       
  1442 ** currently entered text seems to form a complete SQL statement or
       
  1443 ** if additional input is needed before sending the text into
       
  1444 ** SQLite for parsing.  These routines return 1 if the input string
       
  1445 ** appears to be a complete SQL statement.  A statement is judged to be
       
  1446 ** complete if it ends with a semicolon token and is not a prefix of a
       
  1447 ** well-formed CREATE TRIGGER statement.  Semicolons that are embedded within
       
  1448 ** string literals or quoted identifier names or comments are not
       
  1449 ** independent tokens (they are part of the token in which they are
       
  1450 ** embedded) and thus do not count as a statement terminator.  Whitespace
       
  1451 ** and comments that follow the final semicolon are ignored.
       
  1452 **
       
  1453 ** These routines return 0 if the statement is incomplete.  If a
       
  1454 ** memory allocation fails, then SQLITE_NOMEM is returned.
       
  1455 **
       
  1456 ** These routines do not parse the SQL statements thus
       
  1457 ** will not detect syntactically incorrect SQL.
       
  1458 **
       
  1459 ** If SQLite has not been initialized using [sqlite3_initialize()] prior 
       
  1460 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
       
  1461 ** automatically by sqlite3_complete16().  If that initialization fails,
       
  1462 ** then the return value from sqlite3_complete16() will be non-zero
       
  1463 ** regardless of whether or not the input SQL is complete.
       
  1464 **
       
  1465 ** Requirements: [H10511] [H10512]
       
  1466 **
       
  1467 ** The input to [sqlite3_complete()] must be a zero-terminated
       
  1468 ** UTF-8 string.
       
  1469 **
       
  1470 ** The input to [sqlite3_complete16()] must be a zero-terminated
       
  1471 ** UTF-16 string in native byte order.
       
  1472 */
       
  1473 SQLITE_API int sqlite3_complete(const char *sql);
       
  1474 SQLITE_API int sqlite3_complete16(const void *sql);
       
  1475 
       
  1476 /*
       
  1477 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400>
       
  1478 **
       
  1479 ** This routine sets a callback function that might be invoked whenever
       
  1480 ** an attempt is made to open a database table that another thread
       
  1481 ** or process has locked.
       
  1482 **
       
  1483 ** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
       
  1484 ** is returned immediately upon encountering the lock. If the busy callback
       
  1485 ** is not NULL, then the callback will be invoked with two arguments.
       
  1486 **
       
  1487 ** The first argument to the handler is a copy of the void* pointer which
       
  1488 ** is the third argument to sqlite3_busy_handler().  The second argument to
       
  1489 ** the handler callback is the number of times that the busy handler has
       
  1490 ** been invoked for this locking event.  If the
       
  1491 ** busy callback returns 0, then no additional attempts are made to
       
  1492 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
       
  1493 ** If the callback returns non-zero, then another attempt
       
  1494 ** is made to open the database for reading and the cycle repeats.
       
  1495 **
       
  1496 ** The presence of a busy handler does not guarantee that it will be invoked
       
  1497 ** when there is lock contention. If SQLite determines that invoking the busy
       
  1498 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
       
  1499 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
       
  1500 ** Consider a scenario where one process is holding a read lock that
       
  1501 ** it is trying to promote to a reserved lock and
       
  1502 ** a second process is holding a reserved lock that it is trying
       
  1503 ** to promote to an exclusive lock.  The first process cannot proceed
       
  1504 ** because it is blocked by the second and the second process cannot
       
  1505 ** proceed because it is blocked by the first.  If both processes
       
  1506 ** invoke the busy handlers, neither will make any progress.  Therefore,
       
  1507 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
       
  1508 ** will induce the first process to release its read lock and allow
       
  1509 ** the second process to proceed.
       
  1510 **
       
  1511 ** The default busy callback is NULL.
       
  1512 **
       
  1513 ** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
       
  1514 ** when SQLite is in the middle of a large transaction where all the
       
  1515 ** changes will not fit into the in-memory cache.  SQLite will
       
  1516 ** already hold a RESERVED lock on the database file, but it needs
       
  1517 ** to promote this lock to EXCLUSIVE so that it can spill cache
       
  1518 ** pages into the database file without harm to concurrent
       
  1519 ** readers.  If it is unable to promote the lock, then the in-memory
       
  1520 ** cache will be left in an inconsistent state and so the error
       
  1521 ** code is promoted from the relatively benign [SQLITE_BUSY] to
       
  1522 ** the more severe [SQLITE_IOERR_BLOCKED].  This error code promotion
       
  1523 ** forces an automatic rollback of the changes.  See the
       
  1524 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
       
  1525 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
       
  1526 ** this is important.
       
  1527 **
       
  1528 ** There can only be a single busy handler defined for each
       
  1529 ** [database connection].  Setting a new busy handler clears any
       
  1530 ** previously set handler.  Note that calling [sqlite3_busy_timeout()]
       
  1531 ** will also set or clear the busy handler.
       
  1532 **
       
  1533 ** The busy callback should not take any actions which modify the
       
  1534 ** database connection that invoked the busy handler.  Any such actions
       
  1535 ** result in undefined behavior.
       
  1536 ** 
       
  1537 ** Requirements:
       
  1538 ** [H12311] [H12312] [H12314] [H12316] [H12318]
       
  1539 **
       
  1540 ** A busy handler must not close the database connection
       
  1541 ** or [prepared statement] that invoked the busy handler.
       
  1542 */
       
  1543 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
       
  1544 
       
  1545 /*
       
  1546 ** CAPI3REF: Set A Busy Timeout {H12340} <S40410>
       
  1547 **
       
  1548 ** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
       
  1549 ** for a specified amount of time when a table is locked.  The handler
       
  1550 ** will sleep multiple times until at least "ms" milliseconds of sleeping
       
  1551 ** have accumulated. {H12343} After "ms" milliseconds of sleeping,
       
  1552 ** the handler returns 0 which causes [sqlite3_step()] to return
       
  1553 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
       
  1554 **
       
  1555 ** Calling this routine with an argument less than or equal to zero
       
  1556 ** turns off all busy handlers.
       
  1557 **
       
  1558 ** There can only be a single busy handler for a particular
       
  1559 ** [database connection] any any given moment.  If another busy handler
       
  1560 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
       
  1561 ** this routine, that other busy handler is cleared.
       
  1562 **
       
  1563 ** Requirements:
       
  1564 ** [H12341] [H12343] [H12344]
       
  1565 */
       
  1566 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
       
  1567 
       
  1568 /*
       
  1569 ** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000>
       
  1570 **
       
  1571 ** Definition: A <b>result table</b> is memory data structure created by the
       
  1572 ** [sqlite3_get_table()] interface.  A result table records the
       
  1573 ** complete query results from one or more queries.
       
  1574 **
       
  1575 ** The table conceptually has a number of rows and columns.  But
       
  1576 ** these numbers are not part of the result table itself.  These
       
  1577 ** numbers are obtained separately.  Let N be the number of rows
       
  1578 ** and M be the number of columns.
       
  1579 **
       
  1580 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
       
  1581 ** There are (N+1)*M elements in the array.  The first M pointers point
       
  1582 ** to zero-terminated strings that  contain the names of the columns.
       
  1583 ** The remaining entries all point to query results.  NULL values result
       
  1584 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
       
  1585 ** string representation as returned by [sqlite3_column_text()].
       
  1586 **
       
  1587 ** A result table might consist of one or more memory allocations.
       
  1588 ** It is not safe to pass a result table directly to [sqlite3_free()].
       
  1589 ** A result table should be deallocated using [sqlite3_free_table()].
       
  1590 **
       
  1591 ** As an example of the result table format, suppose a query result
       
  1592 ** is as follows:
       
  1593 **
       
  1594 ** <blockquote><pre>
       
  1595 **        Name        | Age
       
  1596 **        -----------------------
       
  1597 **        Alice       | 43
       
  1598 **        Bob         | 28
       
  1599 **        Cindy       | 21
       
  1600 ** </pre></blockquote>
       
  1601 **
       
  1602 ** There are two column (M==2) and three rows (N==3).  Thus the
       
  1603 ** result table has 8 entries.  Suppose the result table is stored
       
  1604 ** in an array names azResult.  Then azResult holds this content:
       
  1605 **
       
  1606 ** <blockquote><pre>
       
  1607 **        azResult&#91;0] = "Name";
       
  1608 **        azResult&#91;1] = "Age";
       
  1609 **        azResult&#91;2] = "Alice";
       
  1610 **        azResult&#91;3] = "43";
       
  1611 **        azResult&#91;4] = "Bob";
       
  1612 **        azResult&#91;5] = "28";
       
  1613 **        azResult&#91;6] = "Cindy";
       
  1614 **        azResult&#91;7] = "21";
       
  1615 ** </pre></blockquote>
       
  1616 **
       
  1617 ** The sqlite3_get_table() function evaluates one or more
       
  1618 ** semicolon-separated SQL statements in the zero-terminated UTF-8
       
  1619 ** string of its 2nd parameter.  It returns a result table to the
       
  1620 ** pointer given in its 3rd parameter.
       
  1621 **
       
  1622 ** After the calling function has finished using the result, it should
       
  1623 ** pass the pointer to the result table to sqlite3_free_table() in order to
       
  1624 ** release the memory that was malloced.  Because of the way the
       
  1625 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
       
  1626 ** function must not try to call [sqlite3_free()] directly.  Only
       
  1627 ** [sqlite3_free_table()] is able to release the memory properly and safely.
       
  1628 **
       
  1629 ** The sqlite3_get_table() interface is implemented as a wrapper around
       
  1630 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
       
  1631 ** to any internal data structures of SQLite.  It uses only the public
       
  1632 ** interface defined here.  As a consequence, errors that occur in the
       
  1633 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
       
  1634 ** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()].
       
  1635 **
       
  1636 ** Requirements:
       
  1637 ** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382]
       
  1638 */
       
  1639 SQLITE_API int sqlite3_get_table(
       
  1640   sqlite3 *db,          /* An open database */
       
  1641   const char *zSql,     /* SQL to be evaluated */
       
  1642   char ***pazResult,    /* Results of the query */
       
  1643   int *pnRow,           /* Number of result rows written here */
       
  1644   int *pnColumn,        /* Number of result columns written here */
       
  1645   char **pzErrmsg       /* Error msg written here */
       
  1646 );
       
  1647 SQLITE_API void sqlite3_free_table(char **result);
       
  1648 
       
  1649 /*
       
  1650 ** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000>
       
  1651 **
       
  1652 ** These routines are work-alikes of the "printf()" family of functions
       
  1653 ** from the standard C library.
       
  1654 **
       
  1655 ** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
       
  1656 ** results into memory obtained from [sqlite3_malloc()].
       
  1657 ** The strings returned by these two routines should be
       
  1658 ** released by [sqlite3_free()].  Both routines return a
       
  1659 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
       
  1660 ** memory to hold the resulting string.
       
  1661 **
       
  1662 ** In sqlite3_snprintf() routine is similar to "snprintf()" from
       
  1663 ** the standard C library.  The result is written into the
       
  1664 ** buffer supplied as the second parameter whose size is given by
       
  1665 ** the first parameter. Note that the order of the
       
  1666 ** first two parameters is reversed from snprintf().  This is an
       
  1667 ** historical accident that cannot be fixed without breaking
       
  1668 ** backwards compatibility.  Note also that sqlite3_snprintf()
       
  1669 ** returns a pointer to its buffer instead of the number of
       
  1670 ** characters actually written into the buffer.  We admit that
       
  1671 ** the number of characters written would be a more useful return
       
  1672 ** value but we cannot change the implementation of sqlite3_snprintf()
       
  1673 ** now without breaking compatibility.
       
  1674 **
       
  1675 ** As long as the buffer size is greater than zero, sqlite3_snprintf()
       
  1676 ** guarantees that the buffer is always zero-terminated.  The first
       
  1677 ** parameter "n" is the total size of the buffer, including space for
       
  1678 ** the zero terminator.  So the longest string that can be completely
       
  1679 ** written will be n-1 characters.
       
  1680 **
       
  1681 ** These routines all implement some additional formatting
       
  1682 ** options that are useful for constructing SQL statements.
       
  1683 ** All of the usual printf() formatting options apply.  In addition, there
       
  1684 ** is are "%q", "%Q", and "%z" options.
       
  1685 **
       
  1686 ** The %q option works like %s in that it substitutes a null-terminated
       
  1687 ** string from the argument list.  But %q also doubles every '\'' character.
       
  1688 ** %q is designed for use inside a string literal.  By doubling each '\''
       
  1689 ** character it escapes that character and allows it to be inserted into
       
  1690 ** the string.
       
  1691 **
       
  1692 ** For example, assume the string variable zText contains text as follows:
       
  1693 **
       
  1694 ** <blockquote><pre>
       
  1695 **  char *zText = "It's a happy day!";
       
  1696 ** </pre></blockquote>
       
  1697 **
       
  1698 ** One can use this text in an SQL statement as follows:
       
  1699 **
       
  1700 ** <blockquote><pre>
       
  1701 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
       
  1702 **  sqlite3_exec(db, zSQL, 0, 0, 0);
       
  1703 **  sqlite3_free(zSQL);
       
  1704 ** </pre></blockquote>
       
  1705 **
       
  1706 ** Because the %q format string is used, the '\'' character in zText
       
  1707 ** is escaped and the SQL generated is as follows:
       
  1708 **
       
  1709 ** <blockquote><pre>
       
  1710 **  INSERT INTO table1 VALUES('It''s a happy day!')
       
  1711 ** </pre></blockquote>
       
  1712 **
       
  1713 ** This is correct.  Had we used %s instead of %q, the generated SQL
       
  1714 ** would have looked like this:
       
  1715 **
       
  1716 ** <blockquote><pre>
       
  1717 **  INSERT INTO table1 VALUES('It's a happy day!');
       
  1718 ** </pre></blockquote>
       
  1719 **
       
  1720 ** This second example is an SQL syntax error.  As a general rule you should
       
  1721 ** always use %q instead of %s when inserting text into a string literal.
       
  1722 **
       
  1723 ** The %Q option works like %q except it also adds single quotes around
       
  1724 ** the outside of the total string.  Additionally, if the parameter in the
       
  1725 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
       
  1726 ** single quotes) in place of the %Q option.  So, for example, one could say:
       
  1727 **
       
  1728 ** <blockquote><pre>
       
  1729 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
       
  1730 **  sqlite3_exec(db, zSQL, 0, 0, 0);
       
  1731 **  sqlite3_free(zSQL);
       
  1732 ** </pre></blockquote>
       
  1733 **
       
  1734 ** The code above will render a correct SQL statement in the zSQL
       
  1735 ** variable even if the zText variable is a NULL pointer.
       
  1736 **
       
  1737 ** The "%z" formatting option works exactly like "%s" with the
       
  1738 ** addition that after the string has been read and copied into
       
  1739 ** the result, [sqlite3_free()] is called on the input string. {END}
       
  1740 **
       
  1741 ** Requirements:
       
  1742 ** [H17403] [H17406] [H17407]
       
  1743 */
       
  1744 SQLITE_API char *sqlite3_mprintf(const char*,...);
       
  1745 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
       
  1746 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
       
  1747 
       
  1748 /*
       
  1749 ** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000>
       
  1750 **
       
  1751 ** The SQLite core  uses these three routines for all of its own
       
  1752 ** internal memory allocation needs. "Core" in the previous sentence
       
  1753 ** does not include operating-system specific VFS implementation.  The
       
  1754 ** Windows VFS uses native malloc() and free() for some operations.
       
  1755 **
       
  1756 ** The sqlite3_malloc() routine returns a pointer to a block
       
  1757 ** of memory at least N bytes in length, where N is the parameter.
       
  1758 ** If sqlite3_malloc() is unable to obtain sufficient free
       
  1759 ** memory, it returns a NULL pointer.  If the parameter N to
       
  1760 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
       
  1761 ** a NULL pointer.
       
  1762 **
       
  1763 ** Calling sqlite3_free() with a pointer previously returned
       
  1764 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
       
  1765 ** that it might be reused.  The sqlite3_free() routine is
       
  1766 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
       
  1767 ** to sqlite3_free() is harmless.  After being freed, memory
       
  1768 ** should neither be read nor written.  Even reading previously freed
       
  1769 ** memory might result in a segmentation fault or other severe error.
       
  1770 ** Memory corruption, a segmentation fault, or other severe error
       
  1771 ** might result if sqlite3_free() is called with a non-NULL pointer that
       
  1772 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
       
  1773 **
       
  1774 ** The sqlite3_realloc() interface attempts to resize a
       
  1775 ** prior memory allocation to be at least N bytes, where N is the
       
  1776 ** second parameter.  The memory allocation to be resized is the first
       
  1777 ** parameter.  If the first parameter to sqlite3_realloc()
       
  1778 ** is a NULL pointer then its behavior is identical to calling
       
  1779 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
       
  1780 ** If the second parameter to sqlite3_realloc() is zero or
       
  1781 ** negative then the behavior is exactly the same as calling
       
  1782 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
       
  1783 ** sqlite3_realloc() returns a pointer to a memory allocation
       
  1784 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
       
  1785 ** If M is the size of the prior allocation, then min(N,M) bytes
       
  1786 ** of the prior allocation are copied into the beginning of buffer returned
       
  1787 ** by sqlite3_realloc() and the prior allocation is freed.
       
  1788 ** If sqlite3_realloc() returns NULL, then the prior allocation
       
  1789 ** is not freed.
       
  1790 **
       
  1791 ** The memory returned by sqlite3_malloc() and sqlite3_realloc()
       
  1792 ** is always aligned to at least an 8 byte boundary. {END}
       
  1793 **
       
  1794 ** The default implementation of the memory allocation subsystem uses
       
  1795 ** the malloc(), realloc() and free() provided by the standard C library.
       
  1796 ** {H17382} However, if SQLite is compiled with the
       
  1797 ** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i>
       
  1798 ** is an integer), then SQLite create a static array of at least
       
  1799 ** <i>NNN</i> bytes in size and uses that array for all of its dynamic
       
  1800 ** memory allocation needs. {END}  Additional memory allocator options
       
  1801 ** may be added in future releases.
       
  1802 **
       
  1803 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
       
  1804 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
       
  1805 ** implementation of these routines to be omitted.  That capability
       
  1806 ** is no longer provided.  Only built-in memory allocators can be used.
       
  1807 **
       
  1808 ** The Windows OS interface layer calls
       
  1809 ** the system malloc() and free() directly when converting
       
  1810 ** filenames between the UTF-8 encoding used by SQLite
       
  1811 ** and whatever filename encoding is used by the particular Windows
       
  1812 ** installation.  Memory allocation errors are detected, but
       
  1813 ** they are reported back as [SQLITE_CANTOPEN] or
       
  1814 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
       
  1815 **
       
  1816 ** Requirements:
       
  1817 ** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318]
       
  1818 ** [H17321] [H17322] [H17323]
       
  1819 **
       
  1820 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
       
  1821 ** must be either NULL or else pointers obtained from a prior
       
  1822 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
       
  1823 ** not yet been released.
       
  1824 **
       
  1825 ** The application must not read or write any part of
       
  1826 ** a block of memory after it has been released using
       
  1827 ** [sqlite3_free()] or [sqlite3_realloc()].
       
  1828 */
       
  1829 SQLITE_API void *sqlite3_malloc(int);
       
  1830 SQLITE_API void *sqlite3_realloc(void*, int);
       
  1831 SQLITE_API void sqlite3_free(void*);
       
  1832 
       
  1833 /*
       
  1834 ** CAPI3REF: Memory Allocator Statistics {H17370} <S30210>
       
  1835 **
       
  1836 ** SQLite provides these two interfaces for reporting on the status
       
  1837 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
       
  1838 ** routines, which form the built-in memory allocation subsystem.
       
  1839 **
       
  1840 ** Requirements:
       
  1841 ** [H17371] [H17373] [H17374] [H17375]
       
  1842 */
       
  1843 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
       
  1844 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
       
  1845 
       
  1846 /*
       
  1847 ** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000>
       
  1848 **
       
  1849 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
       
  1850 ** select random [ROWID | ROWIDs] when inserting new records into a table that
       
  1851 ** already uses the largest possible [ROWID].  The PRNG is also used for
       
  1852 ** the build-in random() and randomblob() SQL functions.  This interface allows
       
  1853 ** applications to access the same PRNG for other purposes.
       
  1854 **
       
  1855 ** A call to this routine stores N bytes of randomness into buffer P.
       
  1856 **
       
  1857 ** The first time this routine is invoked (either internally or by
       
  1858 ** the application) the PRNG is seeded using randomness obtained
       
  1859 ** from the xRandomness method of the default [sqlite3_vfs] object.
       
  1860 ** On all subsequent invocations, the pseudo-randomness is generated
       
  1861 ** internally and without recourse to the [sqlite3_vfs] xRandomness
       
  1862 ** method.
       
  1863 **
       
  1864 ** Requirements:
       
  1865 ** [H17392]
       
  1866 */
       
  1867 SQLITE_API void sqlite3_randomness(int N, void *P);
       
  1868 
       
  1869 /*
       
  1870 ** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100>
       
  1871 **
       
  1872 ** This routine registers a authorizer callback with a particular
       
  1873 ** [database connection], supplied in the first argument.
       
  1874 ** The authorizer callback is invoked as SQL statements are being compiled
       
  1875 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
       
  1876 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  At various
       
  1877 ** points during the compilation process, as logic is being created
       
  1878 ** to perform various actions, the authorizer callback is invoked to
       
  1879 ** see if those actions are allowed.  The authorizer callback should
       
  1880 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
       
  1881 ** specific action but allow the SQL statement to continue to be
       
  1882 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
       
  1883 ** rejected with an error.  If the authorizer callback returns
       
  1884 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
       
  1885 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
       
  1886 ** the authorizer will fail with an error message.
       
  1887 **
       
  1888 ** When the callback returns [SQLITE_OK], that means the operation
       
  1889 ** requested is ok.  When the callback returns [SQLITE_DENY], the
       
  1890 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
       
  1891 ** authorizer will fail with an error message explaining that
       
  1892 ** access is denied. 
       
  1893 **
       
  1894 ** The first parameter to the authorizer callback is a copy of the third
       
  1895 ** parameter to the sqlite3_set_authorizer() interface. The second parameter
       
  1896 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
       
  1897 ** the particular action to be authorized. The third through sixth parameters
       
  1898 ** to the callback are zero-terminated strings that contain additional
       
  1899 ** details about the action to be authorized.
       
  1900 **
       
  1901 ** If the action code is [SQLITE_READ]
       
  1902 ** and the callback returns [SQLITE_IGNORE] then the
       
  1903 ** [prepared statement] statement is constructed to substitute
       
  1904 ** a NULL value in place of the table column that would have
       
  1905 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
       
  1906 ** return can be used to deny an untrusted user access to individual
       
  1907 ** columns of a table.
       
  1908 ** If the action code is [SQLITE_DELETE] and the callback returns
       
  1909 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
       
  1910 ** [truncate optimization] is disabled and all rows are deleted individually.
       
  1911 **
       
  1912 ** An authorizer is used when [sqlite3_prepare | preparing]
       
  1913 ** SQL statements from an untrusted source, to ensure that the SQL statements
       
  1914 ** do not try to access data they are not allowed to see, or that they do not
       
  1915 ** try to execute malicious statements that damage the database.  For
       
  1916 ** example, an application may allow a user to enter arbitrary
       
  1917 ** SQL queries for evaluation by a database.  But the application does
       
  1918 ** not want the user to be able to make arbitrary changes to the
       
  1919 ** database.  An authorizer could then be put in place while the
       
  1920 ** user-entered SQL is being [sqlite3_prepare | prepared] that
       
  1921 ** disallows everything except [SELECT] statements.
       
  1922 **
       
  1923 ** Applications that need to process SQL from untrusted sources
       
  1924 ** might also consider lowering resource limits using [sqlite3_limit()]
       
  1925 ** and limiting database size using the [max_page_count] [PRAGMA]
       
  1926 ** in addition to using an authorizer.
       
  1927 **
       
  1928 ** Only a single authorizer can be in place on a database connection
       
  1929 ** at a time.  Each call to sqlite3_set_authorizer overrides the
       
  1930 ** previous call.  Disable the authorizer by installing a NULL callback.
       
  1931 ** The authorizer is disabled by default.
       
  1932 **
       
  1933 ** The authorizer callback must not do anything that will modify
       
  1934 ** the database connection that invoked the authorizer callback.
       
  1935 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  1936 ** database connections for the meaning of "modify" in this paragraph.
       
  1937 **
       
  1938 ** When [sqlite3_prepare_v2()] is used to prepare a statement, the
       
  1939 ** statement might be re-prepared during [sqlite3_step()] due to a 
       
  1940 ** schema change.  Hence, the application should ensure that the
       
  1941 ** correct authorizer callback remains in place during the [sqlite3_step()].
       
  1942 **
       
  1943 ** Note that the authorizer callback is invoked only during
       
  1944 ** [sqlite3_prepare()] or its variants.  Authorization is not
       
  1945 ** performed during statement evaluation in [sqlite3_step()], unless
       
  1946 ** as stated in the previous paragraph, sqlite3_step() invokes
       
  1947 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
       
  1948 **
       
  1949 ** Requirements:
       
  1950 ** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510]
       
  1951 ** [H12511] [H12512] [H12520] [H12521] [H12522]
       
  1952 */
       
  1953 SQLITE_API int sqlite3_set_authorizer(
       
  1954   sqlite3*,
       
  1955   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
       
  1956   void *pUserData
       
  1957 );
       
  1958 
       
  1959 /*
       
  1960 ** CAPI3REF: Authorizer Return Codes {H12590} <H12500>
       
  1961 **
       
  1962 ** The [sqlite3_set_authorizer | authorizer callback function] must
       
  1963 ** return either [SQLITE_OK] or one of these two constants in order
       
  1964 ** to signal SQLite whether or not the action is permitted.  See the
       
  1965 ** [sqlite3_set_authorizer | authorizer documentation] for additional
       
  1966 ** information.
       
  1967 */
       
  1968 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
       
  1969 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
       
  1970 
       
  1971 /*
       
  1972 ** CAPI3REF: Authorizer Action Codes {H12550} <H12500>
       
  1973 **
       
  1974 ** The [sqlite3_set_authorizer()] interface registers a callback function
       
  1975 ** that is invoked to authorize certain SQL statement actions.  The
       
  1976 ** second parameter to the callback is an integer code that specifies
       
  1977 ** what action is being authorized.  These are the integer action codes that
       
  1978 ** the authorizer callback may be passed.
       
  1979 **
       
  1980 ** These action code values signify what kind of operation is to be
       
  1981 ** authorized.  The 3rd and 4th parameters to the authorization
       
  1982 ** callback function will be parameters or NULL depending on which of these
       
  1983 ** codes is used as the second parameter.  The 5th parameter to the
       
  1984 ** authorizer callback is the name of the database ("main", "temp",
       
  1985 ** etc.) if applicable.  The 6th parameter to the authorizer callback
       
  1986 ** is the name of the inner-most trigger or view that is responsible for
       
  1987 ** the access attempt or NULL if this access attempt is directly from
       
  1988 ** top-level SQL code.
       
  1989 **
       
  1990 ** Requirements:
       
  1991 ** [H12551] [H12552] [H12553] [H12554]
       
  1992 */
       
  1993 /******************************************* 3rd ************ 4th ***********/
       
  1994 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
       
  1995 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
       
  1996 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
       
  1997 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
       
  1998 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
       
  1999 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
       
  2000 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
       
  2001 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
       
  2002 #define SQLITE_DELETE                9   /* Table Name      NULL            */
       
  2003 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
       
  2004 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
       
  2005 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
       
  2006 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
       
  2007 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
       
  2008 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
       
  2009 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
       
  2010 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
       
  2011 #define SQLITE_INSERT               18   /* Table Name      NULL            */
       
  2012 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
       
  2013 #define SQLITE_READ                 20   /* Table Name      Column Name     */
       
  2014 #define SQLITE_SELECT               21   /* NULL            NULL            */
       
  2015 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
       
  2016 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
       
  2017 #define SQLITE_ATTACH               24   /* Filename        NULL            */
       
  2018 #define SQLITE_DETACH               25   /* Database Name   NULL            */
       
  2019 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
       
  2020 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
       
  2021 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
       
  2022 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
       
  2023 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
       
  2024 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
       
  2025 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
       
  2026 #define SQLITE_COPY                  0   /* No longer used */
       
  2027 
       
  2028 /*
       
  2029 ** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400>
       
  2030 ** EXPERIMENTAL
       
  2031 **
       
  2032 ** These routines register callback functions that can be used for
       
  2033 ** tracing and profiling the execution of SQL statements.
       
  2034 **
       
  2035 ** The callback function registered by sqlite3_trace() is invoked at
       
  2036 ** various times when an SQL statement is being run by [sqlite3_step()].
       
  2037 ** The callback returns a UTF-8 rendering of the SQL statement text
       
  2038 ** as the statement first begins executing.  Additional callbacks occur
       
  2039 ** as each triggered subprogram is entered.  The callbacks for triggers
       
  2040 ** contain a UTF-8 SQL comment that identifies the trigger.
       
  2041 **
       
  2042 ** The callback function registered by sqlite3_profile() is invoked
       
  2043 ** as each SQL statement finishes.  The profile callback contains
       
  2044 ** the original statement text and an estimate of wall-clock time
       
  2045 ** of how long that statement took to run.
       
  2046 **
       
  2047 ** Requirements:
       
  2048 ** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289]
       
  2049 ** [H12290]
       
  2050 */
       
  2051 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
       
  2052 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
       
  2053    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
       
  2054 
       
  2055 /*
       
  2056 ** CAPI3REF: Query Progress Callbacks {H12910} <S60400>
       
  2057 **
       
  2058 ** This routine configures a callback function - the
       
  2059 ** progress callback - that is invoked periodically during long
       
  2060 ** running calls to [sqlite3_exec()], [sqlite3_step()] and
       
  2061 ** [sqlite3_get_table()].  An example use for this
       
  2062 ** interface is to keep a GUI updated during a large query.
       
  2063 **
       
  2064 ** If the progress callback returns non-zero, the operation is
       
  2065 ** interrupted.  This feature can be used to implement a
       
  2066 ** "Cancel" button on a GUI progress dialog box.
       
  2067 **
       
  2068 ** The progress handler must not do anything that will modify
       
  2069 ** the database connection that invoked the progress handler.
       
  2070 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  2071 ** database connections for the meaning of "modify" in this paragraph.
       
  2072 **
       
  2073 ** Requirements:
       
  2074 ** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918]
       
  2075 **
       
  2076 */
       
  2077 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
       
  2078 
       
  2079 /*
       
  2080 ** CAPI3REF: Opening A New Database Connection {H12700} <S40200>
       
  2081 **
       
  2082 ** These routines open an SQLite database file whose name is given by the
       
  2083 ** filename argument. The filename argument is interpreted as UTF-8 for
       
  2084 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
       
  2085 ** order for sqlite3_open16(). A [database connection] handle is usually
       
  2086 ** returned in *ppDb, even if an error occurs.  The only exception is that
       
  2087 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
       
  2088 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
       
  2089 ** object. If the database is opened (and/or created) successfully, then
       
  2090 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.  The
       
  2091 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
       
  2092 ** an English language description of the error.
       
  2093 **
       
  2094 ** The default encoding for the database will be UTF-8 if
       
  2095 ** sqlite3_open() or sqlite3_open_v2() is called and
       
  2096 ** UTF-16 in the native byte order if sqlite3_open16() is used.
       
  2097 **
       
  2098 ** Whether or not an error occurs when it is opened, resources
       
  2099 ** associated with the [database connection] handle should be released by
       
  2100 ** passing it to [sqlite3_close()] when it is no longer required.
       
  2101 **
       
  2102 ** The sqlite3_open_v2() interface works like sqlite3_open()
       
  2103 ** except that it accepts two additional parameters for additional control
       
  2104 ** over the new database connection.  The flags parameter can take one of
       
  2105 ** the following three values, optionally combined with the 
       
  2106 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
       
  2107 ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:
       
  2108 **
       
  2109 ** <dl>
       
  2110 ** <dt>[SQLITE_OPEN_READONLY]</dt>
       
  2111 ** <dd>The database is opened in read-only mode.  If the database does not
       
  2112 ** already exist, an error is returned.</dd>
       
  2113 **
       
  2114 ** <dt>[SQLITE_OPEN_READWRITE]</dt>
       
  2115 ** <dd>The database is opened for reading and writing if possible, or reading
       
  2116 ** only if the file is write protected by the operating system.  In either
       
  2117 ** case the database must already exist, otherwise an error is returned.</dd>
       
  2118 **
       
  2119 ** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
       
  2120 ** <dd>The database is opened for reading and writing, and is creates it if
       
  2121 ** it does not already exist. This is the behavior that is always used for
       
  2122 ** sqlite3_open() and sqlite3_open16().</dd>
       
  2123 ** </dl>
       
  2124 **
       
  2125 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
       
  2126 ** combinations shown above or one of the combinations shown above combined
       
  2127 ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
       
  2128 ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags,
       
  2129 ** then the behavior is undefined.
       
  2130 **
       
  2131 ** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
       
  2132 ** opens in the multi-thread [threading mode] as long as the single-thread
       
  2133 ** mode has not been set at compile-time or start-time.  If the
       
  2134 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
       
  2135 ** in the serialized [threading mode] unless single-thread was
       
  2136 ** previously selected at compile-time or start-time.
       
  2137 ** The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
       
  2138 ** eligible to use [shared cache mode], regardless of whether or not shared
       
  2139 ** cache is enabled using [sqlite3_enable_shared_cache()].  The
       
  2140 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
       
  2141 ** participate in [shared cache mode] even if it is enabled.
       
  2142 **
       
  2143 ** If the filename is ":memory:", then a private, temporary in-memory database
       
  2144 ** is created for the connection.  This in-memory database will vanish when
       
  2145 ** the database connection is closed.  Future versions of SQLite might
       
  2146 ** make use of additional special filenames that begin with the ":" character.
       
  2147 ** It is recommended that when a database filename actually does begin with
       
  2148 ** a ":" character you should prefix the filename with a pathname such as
       
  2149 ** "./" to avoid ambiguity.
       
  2150 **
       
  2151 ** If the filename is an empty string, then a private, temporary
       
  2152 ** on-disk database will be created.  This private database will be
       
  2153 ** automatically deleted as soon as the database connection is closed.
       
  2154 **
       
  2155 ** The fourth parameter to sqlite3_open_v2() is the name of the
       
  2156 ** [sqlite3_vfs] object that defines the operating system interface that
       
  2157 ** the new database connection should use.  If the fourth parameter is
       
  2158 ** a NULL pointer then the default [sqlite3_vfs] object is used.
       
  2159 **
       
  2160 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
       
  2161 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
       
  2162 ** codepage is currently defined.  Filenames containing international
       
  2163 ** characters must be converted to UTF-8 prior to passing them into
       
  2164 ** sqlite3_open() or sqlite3_open_v2().
       
  2165 **
       
  2166 ** Requirements:
       
  2167 ** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711]
       
  2168 ** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723]
       
  2169 */
       
  2170 SQLITE_API int sqlite3_open(
       
  2171   const char *filename,   /* Database filename (UTF-8) */
       
  2172   sqlite3 **ppDb          /* OUT: SQLite db handle */
       
  2173 );
       
  2174 SQLITE_API int sqlite3_open16(
       
  2175   const void *filename,   /* Database filename (UTF-16) */
       
  2176   sqlite3 **ppDb          /* OUT: SQLite db handle */
       
  2177 );
       
  2178 SQLITE_API int sqlite3_open_v2(
       
  2179   const char *filename,   /* Database filename (UTF-8) */
       
  2180   sqlite3 **ppDb,         /* OUT: SQLite db handle */
       
  2181   int flags,              /* Flags */
       
  2182   const char *zVfs        /* Name of VFS module to use */
       
  2183 );
       
  2184 
       
  2185 /*
       
  2186 ** CAPI3REF: Error Codes And Messages {H12800} <S60200>
       
  2187 **
       
  2188 ** The sqlite3_errcode() interface returns the numeric [result code] or
       
  2189 ** [extended result code] for the most recent failed sqlite3_* API call
       
  2190 ** associated with a [database connection]. If a prior API call failed
       
  2191 ** but the most recent API call succeeded, the return value from
       
  2192 ** sqlite3_errcode() is undefined.  The sqlite3_extended_errcode()
       
  2193 ** interface is the same except that it always returns the 
       
  2194 ** [extended result code] even when extended result codes are
       
  2195 ** disabled.
       
  2196 **
       
  2197 ** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
       
  2198 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
       
  2199 ** Memory to hold the error message string is managed internally.
       
  2200 ** The application does not need to worry about freeing the result.
       
  2201 ** However, the error string might be overwritten or deallocated by
       
  2202 ** subsequent calls to other SQLite interface functions.
       
  2203 **
       
  2204 ** When the serialized [threading mode] is in use, it might be the
       
  2205 ** case that a second error occurs on a separate thread in between
       
  2206 ** the time of the first error and the call to these interfaces.
       
  2207 ** When that happens, the second error will be reported since these
       
  2208 ** interfaces always report the most recent result.  To avoid
       
  2209 ** this, each thread can obtain exclusive use of the [database connection] D
       
  2210 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
       
  2211 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
       
  2212 ** all calls to the interfaces listed here are completed.
       
  2213 **
       
  2214 ** If an interface fails with SQLITE_MISUSE, that means the interface
       
  2215 ** was invoked incorrectly by the application.  In that case, the
       
  2216 ** error code and message may or may not be set.
       
  2217 **
       
  2218 ** Requirements:
       
  2219 ** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809]
       
  2220 */
       
  2221 SQLITE_API int sqlite3_errcode(sqlite3 *db);
       
  2222 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
       
  2223 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
       
  2224 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
       
  2225 
       
  2226 /*
       
  2227 ** CAPI3REF: SQL Statement Object {H13000} <H13010>
       
  2228 ** KEYWORDS: {prepared statement} {prepared statements}
       
  2229 **
       
  2230 ** An instance of this object represents a single SQL statement.
       
  2231 ** This object is variously known as a "prepared statement" or a
       
  2232 ** "compiled SQL statement" or simply as a "statement".
       
  2233 **
       
  2234 ** The life of a statement object goes something like this:
       
  2235 **
       
  2236 ** <ol>
       
  2237 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
       
  2238 **      function.
       
  2239 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
       
  2240 **      interfaces.
       
  2241 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
       
  2242 ** <li> Reset the statement using [sqlite3_reset()] then go back
       
  2243 **      to step 2.  Do this zero or more times.
       
  2244 ** <li> Destroy the object using [sqlite3_finalize()].
       
  2245 ** </ol>
       
  2246 **
       
  2247 ** Refer to documentation on individual methods above for additional
       
  2248 ** information.
       
  2249 */
       
  2250 typedef struct sqlite3_stmt sqlite3_stmt;
       
  2251 
       
  2252 /*
       
  2253 ** CAPI3REF: Run-time Limits {H12760} <S20600>
       
  2254 **
       
  2255 ** This interface allows the size of various constructs to be limited
       
  2256 ** on a connection by connection basis.  The first parameter is the
       
  2257 ** [database connection] whose limit is to be set or queried.  The
       
  2258 ** second parameter is one of the [limit categories] that define a
       
  2259 ** class of constructs to be size limited.  The third parameter is the
       
  2260 ** new limit for that construct.  The function returns the old limit.
       
  2261 **
       
  2262 ** If the new limit is a negative number, the limit is unchanged.
       
  2263 ** For the limit category of SQLITE_LIMIT_XYZ there is a 
       
  2264 ** [limits | hard upper bound]
       
  2265 ** set by a compile-time C preprocessor macro named 
       
  2266 ** [limits | SQLITE_MAX_XYZ].
       
  2267 ** (The "_LIMIT_" in the name is changed to "_MAX_".)
       
  2268 ** Attempts to increase a limit above its hard upper bound are
       
  2269 ** silently truncated to the hard upper limit.
       
  2270 **
       
  2271 ** Run time limits are intended for use in applications that manage
       
  2272 ** both their own internal database and also databases that are controlled
       
  2273 ** by untrusted external sources.  An example application might be a
       
  2274 ** web browser that has its own databases for storing history and
       
  2275 ** separate databases controlled by JavaScript applications downloaded
       
  2276 ** off the Internet.  The internal databases can be given the
       
  2277 ** large, default limits.  Databases managed by external sources can
       
  2278 ** be given much smaller limits designed to prevent a denial of service
       
  2279 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
       
  2280 ** interface to further control untrusted SQL.  The size of the database
       
  2281 ** created by an untrusted script can be contained using the
       
  2282 ** [max_page_count] [PRAGMA].
       
  2283 **
       
  2284 ** New run-time limit categories may be added in future releases.
       
  2285 **
       
  2286 ** Requirements:
       
  2287 ** [H12762] [H12766] [H12769]
       
  2288 */
       
  2289 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
       
  2290 
       
  2291 /*
       
  2292 ** CAPI3REF: Run-Time Limit Categories {H12790} <H12760>
       
  2293 ** KEYWORDS: {limit category} {limit categories}
       
  2294 **
       
  2295 ** These constants define various performance limits
       
  2296 ** that can be lowered at run-time using [sqlite3_limit()].
       
  2297 ** The synopsis of the meanings of the various limits is shown below.
       
  2298 ** Additional information is available at [limits | Limits in SQLite].
       
  2299 **
       
  2300 ** <dl>
       
  2301 ** <dt>SQLITE_LIMIT_LENGTH</dt>
       
  2302 ** <dd>The maximum size of any string or BLOB or table row.<dd>
       
  2303 **
       
  2304 ** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
       
  2305 ** <dd>The maximum length of an SQL statement.</dd>
       
  2306 **
       
  2307 ** <dt>SQLITE_LIMIT_COLUMN</dt>
       
  2308 ** <dd>The maximum number of columns in a table definition or in the
       
  2309 ** result set of a [SELECT] or the maximum number of columns in an index
       
  2310 ** or in an ORDER BY or GROUP BY clause.</dd>
       
  2311 **
       
  2312 ** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
       
  2313 ** <dd>The maximum depth of the parse tree on any expression.</dd>
       
  2314 **
       
  2315 ** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
       
  2316 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>
       
  2317 **
       
  2318 ** <dt>SQLITE_LIMIT_VDBE_OP</dt>
       
  2319 ** <dd>The maximum number of instructions in a virtual machine program
       
  2320 ** used to implement an SQL statement.</dd>
       
  2321 **
       
  2322 ** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
       
  2323 ** <dd>The maximum number of arguments on a function.</dd>
       
  2324 **
       
  2325 ** <dt>SQLITE_LIMIT_ATTACHED</dt>
       
  2326 ** <dd>The maximum number of [ATTACH | attached databases].</dd>
       
  2327 **
       
  2328 ** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
       
  2329 ** <dd>The maximum length of the pattern argument to the [LIKE] or
       
  2330 ** [GLOB] operators.</dd>
       
  2331 **
       
  2332 ** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
       
  2333 ** <dd>The maximum number of variables in an SQL statement that can
       
  2334 ** be bound.</dd>
       
  2335 **
       
  2336 ** <dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
       
  2337 ** <dd>The maximum depth of recursion for triggers.</dd>
       
  2338 ** </dl>
       
  2339 */
       
  2340 #define SQLITE_LIMIT_LENGTH                    0
       
  2341 #define SQLITE_LIMIT_SQL_LENGTH                1
       
  2342 #define SQLITE_LIMIT_COLUMN                    2
       
  2343 #define SQLITE_LIMIT_EXPR_DEPTH                3
       
  2344 #define SQLITE_LIMIT_COMPOUND_SELECT           4
       
  2345 #define SQLITE_LIMIT_VDBE_OP                   5
       
  2346 #define SQLITE_LIMIT_FUNCTION_ARG              6
       
  2347 #define SQLITE_LIMIT_ATTACHED                  7
       
  2348 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
       
  2349 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
       
  2350 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
       
  2351 
       
  2352 /*
       
  2353 ** CAPI3REF: Compiling An SQL Statement {H13010} <S10000>
       
  2354 ** KEYWORDS: {SQL statement compiler}
       
  2355 **
       
  2356 ** To execute an SQL query, it must first be compiled into a byte-code
       
  2357 ** program using one of these routines.
       
  2358 **
       
  2359 ** The first argument, "db", is a [database connection] obtained from a
       
  2360 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
       
  2361 ** [sqlite3_open16()].  The database connection must not have been closed.
       
  2362 **
       
  2363 ** The second argument, "zSql", is the statement to be compiled, encoded
       
  2364 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
       
  2365 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
       
  2366 ** use UTF-16.
       
  2367 **
       
  2368 ** If the nByte argument is less than zero, then zSql is read up to the
       
  2369 ** first zero terminator. If nByte is non-negative, then it is the maximum
       
  2370 ** number of  bytes read from zSql.  When nByte is non-negative, the
       
  2371 ** zSql string ends at either the first '\000' or '\u0000' character or
       
  2372 ** the nByte-th byte, whichever comes first. If the caller knows
       
  2373 ** that the supplied string is nul-terminated, then there is a small
       
  2374 ** performance advantage to be gained by passing an nByte parameter that
       
  2375 ** is equal to the number of bytes in the input string <i>including</i>
       
  2376 ** the nul-terminator bytes.
       
  2377 **
       
  2378 ** If pzTail is not NULL then *pzTail is made to point to the first byte
       
  2379 ** past the end of the first SQL statement in zSql.  These routines only
       
  2380 ** compile the first statement in zSql, so *pzTail is left pointing to
       
  2381 ** what remains uncompiled.
       
  2382 **
       
  2383 ** *ppStmt is left pointing to a compiled [prepared statement] that can be
       
  2384 ** executed using [sqlite3_step()].  If there is an error, *ppStmt is set
       
  2385 ** to NULL.  If the input text contains no SQL (if the input is an empty
       
  2386 ** string or a comment) then *ppStmt is set to NULL.
       
  2387 ** The calling procedure is responsible for deleting the compiled
       
  2388 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
       
  2389 ** ppStmt may not be NULL.
       
  2390 **
       
  2391 ** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned.
       
  2392 **
       
  2393 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
       
  2394 ** recommended for all new programs. The two older interfaces are retained
       
  2395 ** for backwards compatibility, but their use is discouraged.
       
  2396 ** In the "v2" interfaces, the prepared statement
       
  2397 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
       
  2398 ** original SQL text. This causes the [sqlite3_step()] interface to
       
  2399 ** behave a differently in two ways:
       
  2400 **
       
  2401 ** <ol>
       
  2402 ** <li>
       
  2403 ** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
       
  2404 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
       
  2405 ** statement and try to run it again.  If the schema has changed in
       
  2406 ** a way that makes the statement no longer valid, [sqlite3_step()] will still
       
  2407 ** return [SQLITE_SCHEMA].  But unlike the legacy behavior, [SQLITE_SCHEMA] is
       
  2408 ** now a fatal error.  Calling [sqlite3_prepare_v2()] again will not make the
       
  2409 ** error go away.  Note: use [sqlite3_errmsg()] to find the text
       
  2410 ** of the parsing error that results in an [SQLITE_SCHEMA] return.
       
  2411 ** </li>
       
  2412 **
       
  2413 ** <li>
       
  2414 ** When an error occurs, [sqlite3_step()] will return one of the detailed
       
  2415 ** [error codes] or [extended error codes].  The legacy behavior was that
       
  2416 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
       
  2417 ** and you would have to make a second call to [sqlite3_reset()] in order
       
  2418 ** to find the underlying cause of the problem. With the "v2" prepare
       
  2419 ** interfaces, the underlying reason for the error is returned immediately.
       
  2420 ** </li>
       
  2421 ** </ol>
       
  2422 **
       
  2423 ** Requirements:
       
  2424 ** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021]
       
  2425 **
       
  2426 */
       
  2427 SQLITE_API int sqlite3_prepare(
       
  2428   sqlite3 *db,            /* Database handle */
       
  2429   const char *zSql,       /* SQL statement, UTF-8 encoded */
       
  2430   int nByte,              /* Maximum length of zSql in bytes. */
       
  2431   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2432   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2433 );
       
  2434 SQLITE_API int sqlite3_prepare_v2(
       
  2435   sqlite3 *db,            /* Database handle */
       
  2436   const char *zSql,       /* SQL statement, UTF-8 encoded */
       
  2437   int nByte,              /* Maximum length of zSql in bytes. */
       
  2438   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2439   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2440 );
       
  2441 SQLITE_API int sqlite3_prepare16(
       
  2442   sqlite3 *db,            /* Database handle */
       
  2443   const void *zSql,       /* SQL statement, UTF-16 encoded */
       
  2444   int nByte,              /* Maximum length of zSql in bytes. */
       
  2445   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2446   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2447 );
       
  2448 SQLITE_API int sqlite3_prepare16_v2(
       
  2449   sqlite3 *db,            /* Database handle */
       
  2450   const void *zSql,       /* SQL statement, UTF-16 encoded */
       
  2451   int nByte,              /* Maximum length of zSql in bytes. */
       
  2452   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2453   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2454 );
       
  2455 
       
  2456 /*
       
  2457 ** CAPI3REF: Retrieving Statement SQL {H13100} <H13000>
       
  2458 **
       
  2459 ** This interface can be used to retrieve a saved copy of the original
       
  2460 ** SQL text used to create a [prepared statement] if that statement was
       
  2461 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
       
  2462 **
       
  2463 ** Requirements:
       
  2464 ** [H13101] [H13102] [H13103]
       
  2465 */
       
  2466 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
       
  2467 
       
  2468 /*
       
  2469 ** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200>
       
  2470 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
       
  2471 **
       
  2472 ** SQLite uses the sqlite3_value object to represent all values
       
  2473 ** that can be stored in a database table. SQLite uses dynamic typing
       
  2474 ** for the values it stores. Values stored in sqlite3_value objects
       
  2475 ** can be integers, floating point values, strings, BLOBs, or NULL.
       
  2476 **
       
  2477 ** An sqlite3_value object may be either "protected" or "unprotected".
       
  2478 ** Some interfaces require a protected sqlite3_value.  Other interfaces
       
  2479 ** will accept either a protected or an unprotected sqlite3_value.
       
  2480 ** Every interface that accepts sqlite3_value arguments specifies
       
  2481 ** whether or not it requires a protected sqlite3_value.
       
  2482 **
       
  2483 ** The terms "protected" and "unprotected" refer to whether or not
       
  2484 ** a mutex is held.  A internal mutex is held for a protected
       
  2485 ** sqlite3_value object but no mutex is held for an unprotected
       
  2486 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
       
  2487 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
       
  2488 ** or if SQLite is run in one of reduced mutex modes 
       
  2489 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
       
  2490 ** then there is no distinction between protected and unprotected
       
  2491 ** sqlite3_value objects and they can be used interchangeably.  However,
       
  2492 ** for maximum code portability it is recommended that applications
       
  2493 ** still make the distinction between between protected and unprotected
       
  2494 ** sqlite3_value objects even when not strictly required.
       
  2495 **
       
  2496 ** The sqlite3_value objects that are passed as parameters into the
       
  2497 ** implementation of [application-defined SQL functions] are protected.
       
  2498 ** The sqlite3_value object returned by
       
  2499 ** [sqlite3_column_value()] is unprotected.
       
  2500 ** Unprotected sqlite3_value objects may only be used with
       
  2501 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
       
  2502 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
       
  2503 ** interfaces require protected sqlite3_value objects.
       
  2504 */
       
  2505 typedef struct Mem sqlite3_value;
       
  2506 
       
  2507 /*
       
  2508 ** CAPI3REF: SQL Function Context Object {H16001} <S20200>
       
  2509 **
       
  2510 ** The context in which an SQL function executes is stored in an
       
  2511 ** sqlite3_context object.  A pointer to an sqlite3_context object
       
  2512 ** is always first parameter to [application-defined SQL functions].
       
  2513 ** The application-defined SQL function implementation will pass this
       
  2514 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
       
  2515 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
       
  2516 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
       
  2517 ** and/or [sqlite3_set_auxdata()].
       
  2518 */
       
  2519 typedef struct sqlite3_context sqlite3_context;
       
  2520 
       
  2521 /*
       
  2522 ** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300>
       
  2523 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
       
  2524 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
       
  2525 **
       
  2526 ** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
       
  2527 ** literals may be replaced by a [parameter] that matches one of following
       
  2528 ** templates:
       
  2529 **
       
  2530 ** <ul>
       
  2531 ** <li>  ?
       
  2532 ** <li>  ?NNN
       
  2533 ** <li>  :VVV
       
  2534 ** <li>  @VVV
       
  2535 ** <li>  $VVV
       
  2536 ** </ul>
       
  2537 **
       
  2538 ** In the templates above, NNN represents an integer literal,
       
  2539 ** and VVV represents an alphanumeric identifer.  The values of these
       
  2540 ** parameters (also called "host parameter names" or "SQL parameters")
       
  2541 ** can be set using the sqlite3_bind_*() routines defined here.
       
  2542 **
       
  2543 ** The first argument to the sqlite3_bind_*() routines is always
       
  2544 ** a pointer to the [sqlite3_stmt] object returned from
       
  2545 ** [sqlite3_prepare_v2()] or its variants.
       
  2546 **
       
  2547 ** The second argument is the index of the SQL parameter to be set.
       
  2548 ** The leftmost SQL parameter has an index of 1.  When the same named
       
  2549 ** SQL parameter is used more than once, second and subsequent
       
  2550 ** occurrences have the same index as the first occurrence.
       
  2551 ** The index for named parameters can be looked up using the
       
  2552 ** [sqlite3_bind_parameter_index()] API if desired.  The index
       
  2553 ** for "?NNN" parameters is the value of NNN.
       
  2554 ** The NNN value must be between 1 and the [sqlite3_limit()]
       
  2555 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
       
  2556 **
       
  2557 ** The third argument is the value to bind to the parameter.
       
  2558 **
       
  2559 ** In those routines that have a fourth argument, its value is the
       
  2560 ** number of bytes in the parameter.  To be clear: the value is the
       
  2561 ** number of <u>bytes</u> in the value, not the number of characters.
       
  2562 ** If the fourth parameter is negative, the length of the string is
       
  2563 ** the number of bytes up to the first zero terminator.
       
  2564 **
       
  2565 ** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
       
  2566 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
       
  2567 ** string after SQLite has finished with it. If the fifth argument is
       
  2568 ** the special value [SQLITE_STATIC], then SQLite assumes that the
       
  2569 ** information is in static, unmanaged space and does not need to be freed.
       
  2570 ** If the fifth argument has the value [SQLITE_TRANSIENT], then
       
  2571 ** SQLite makes its own private copy of the data immediately, before
       
  2572 ** the sqlite3_bind_*() routine returns.
       
  2573 **
       
  2574 ** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
       
  2575 ** is filled with zeroes.  A zeroblob uses a fixed amount of memory
       
  2576 ** (just an integer to hold its size) while it is being processed.
       
  2577 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
       
  2578 ** content is later written using
       
  2579 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
       
  2580 ** A negative value for the zeroblob results in a zero-length BLOB.
       
  2581 **
       
  2582 ** The sqlite3_bind_*() routines must be called after
       
  2583 ** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
       
  2584 ** before [sqlite3_step()].
       
  2585 ** Bindings are not cleared by the [sqlite3_reset()] routine.
       
  2586 ** Unbound parameters are interpreted as NULL.
       
  2587 **
       
  2588 ** These routines return [SQLITE_OK] on success or an error code if
       
  2589 ** anything goes wrong.  [SQLITE_RANGE] is returned if the parameter
       
  2590 ** index is out of range.  [SQLITE_NOMEM] is returned if malloc() fails.
       
  2591 ** [SQLITE_MISUSE] might be returned if these routines are called on a
       
  2592 ** virtual machine that is the wrong state or which has already been finalized.
       
  2593 ** Detection of misuse is unreliable.  Applications should not depend
       
  2594 ** on SQLITE_MISUSE returns.  SQLITE_MISUSE is intended to indicate a
       
  2595 ** a logic error in the application.  Future versions of SQLite might
       
  2596 ** panic rather than return SQLITE_MISUSE.
       
  2597 **
       
  2598 ** See also: [sqlite3_bind_parameter_count()],
       
  2599 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
       
  2600 **
       
  2601 ** Requirements:
       
  2602 ** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527]
       
  2603 ** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551]
       
  2604 **
       
  2605 */
       
  2606 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
       
  2607 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
       
  2608 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
       
  2609 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
       
  2610 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
       
  2611 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
       
  2612 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
       
  2613 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
       
  2614 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
       
  2615 
       
  2616 /*
       
  2617 ** CAPI3REF: Number Of SQL Parameters {H13600} <S70300>
       
  2618 **
       
  2619 ** This routine can be used to find the number of [SQL parameters]
       
  2620 ** in a [prepared statement].  SQL parameters are tokens of the
       
  2621 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
       
  2622 ** placeholders for values that are [sqlite3_bind_blob | bound]
       
  2623 ** to the parameters at a later time.
       
  2624 **
       
  2625 ** This routine actually returns the index of the largest (rightmost)
       
  2626 ** parameter. For all forms except ?NNN, this will correspond to the
       
  2627 ** number of unique parameters.  If parameters of the ?NNN are used,
       
  2628 ** there may be gaps in the list.
       
  2629 **
       
  2630 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  2631 ** [sqlite3_bind_parameter_name()], and
       
  2632 ** [sqlite3_bind_parameter_index()].
       
  2633 **
       
  2634 ** Requirements:
       
  2635 ** [H13601]
       
  2636 */
       
  2637 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
       
  2638 
       
  2639 /*
       
  2640 ** CAPI3REF: Name Of A Host Parameter {H13620} <S70300>
       
  2641 **
       
  2642 ** This routine returns a pointer to the name of the n-th
       
  2643 ** [SQL parameter] in a [prepared statement].
       
  2644 ** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
       
  2645 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
       
  2646 ** respectively.
       
  2647 ** In other words, the initial ":" or "$" or "@" or "?"
       
  2648 ** is included as part of the name.
       
  2649 ** Parameters of the form "?" without a following integer have no name
       
  2650 ** and are also referred to as "anonymous parameters".
       
  2651 **
       
  2652 ** The first host parameter has an index of 1, not 0.
       
  2653 **
       
  2654 ** If the value n is out of range or if the n-th parameter is
       
  2655 ** nameless, then NULL is returned.  The returned string is
       
  2656 ** always in UTF-8 encoding even if the named parameter was
       
  2657 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
       
  2658 ** [sqlite3_prepare16_v2()].
       
  2659 **
       
  2660 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  2661 ** [sqlite3_bind_parameter_count()], and
       
  2662 ** [sqlite3_bind_parameter_index()].
       
  2663 **
       
  2664 ** Requirements:
       
  2665 ** [H13621]
       
  2666 */
       
  2667 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
       
  2668 
       
  2669 /*
       
  2670 ** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300>
       
  2671 **
       
  2672 ** Return the index of an SQL parameter given its name.  The
       
  2673 ** index value returned is suitable for use as the second
       
  2674 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  A zero
       
  2675 ** is returned if no matching parameter is found.  The parameter
       
  2676 ** name must be given in UTF-8 even if the original statement
       
  2677 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
       
  2678 **
       
  2679 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  2680 ** [sqlite3_bind_parameter_count()], and
       
  2681 ** [sqlite3_bind_parameter_index()].
       
  2682 **
       
  2683 ** Requirements:
       
  2684 ** [H13641]
       
  2685 */
       
  2686 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
       
  2687 
       
  2688 /*
       
  2689 ** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300>
       
  2690 **
       
  2691 ** Contrary to the intuition of many, [sqlite3_reset()] does not reset
       
  2692 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
       
  2693 ** Use this routine to reset all host parameters to NULL.
       
  2694 **
       
  2695 ** Requirements:
       
  2696 ** [H13661]
       
  2697 */
       
  2698 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
       
  2699 
       
  2700 /*
       
  2701 ** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700>
       
  2702 **
       
  2703 ** Return the number of columns in the result set returned by the
       
  2704 ** [prepared statement]. This routine returns 0 if pStmt is an SQL
       
  2705 ** statement that does not return data (for example an [UPDATE]).
       
  2706 **
       
  2707 ** Requirements:
       
  2708 ** [H13711]
       
  2709 */
       
  2710 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
       
  2711 
       
  2712 /*
       
  2713 ** CAPI3REF: Column Names In A Result Set {H13720} <S10700>
       
  2714 **
       
  2715 ** These routines return the name assigned to a particular column
       
  2716 ** in the result set of a [SELECT] statement.  The sqlite3_column_name()
       
  2717 ** interface returns a pointer to a zero-terminated UTF-8 string
       
  2718 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
       
  2719 ** UTF-16 string.  The first parameter is the [prepared statement]
       
  2720 ** that implements the [SELECT] statement. The second parameter is the
       
  2721 ** column number.  The leftmost column is number 0.
       
  2722 **
       
  2723 ** The returned string pointer is valid until either the [prepared statement]
       
  2724 ** is destroyed by [sqlite3_finalize()] or until the next call to
       
  2725 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
       
  2726 **
       
  2727 ** If sqlite3_malloc() fails during the processing of either routine
       
  2728 ** (for example during a conversion from UTF-8 to UTF-16) then a
       
  2729 ** NULL pointer is returned.
       
  2730 **
       
  2731 ** The name of a result column is the value of the "AS" clause for
       
  2732 ** that column, if there is an AS clause.  If there is no AS clause
       
  2733 ** then the name of the column is unspecified and may change from
       
  2734 ** one release of SQLite to the next.
       
  2735 **
       
  2736 ** Requirements:
       
  2737 ** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727]
       
  2738 */
       
  2739 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
       
  2740 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
       
  2741 
       
  2742 /*
       
  2743 ** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700>
       
  2744 **
       
  2745 ** These routines provide a means to determine what column of what
       
  2746 ** table in which database a result of a [SELECT] statement comes from.
       
  2747 ** The name of the database or table or column can be returned as
       
  2748 ** either a UTF-8 or UTF-16 string.  The _database_ routines return
       
  2749 ** the database name, the _table_ routines return the table name, and
       
  2750 ** the origin_ routines return the column name.
       
  2751 ** The returned string is valid until the [prepared statement] is destroyed
       
  2752 ** using [sqlite3_finalize()] or until the same information is requested
       
  2753 ** again in a different encoding.
       
  2754 **
       
  2755 ** The names returned are the original un-aliased names of the
       
  2756 ** database, table, and column.
       
  2757 **
       
  2758 ** The first argument to the following calls is a [prepared statement].
       
  2759 ** These functions return information about the Nth column returned by
       
  2760 ** the statement, where N is the second function argument.
       
  2761 **
       
  2762 ** If the Nth column returned by the statement is an expression or
       
  2763 ** subquery and is not a column value, then all of these functions return
       
  2764 ** NULL.  These routine might also return NULL if a memory allocation error
       
  2765 ** occurs.  Otherwise, they return the name of the attached database, table
       
  2766 ** and column that query result column was extracted from.
       
  2767 **
       
  2768 ** As with all other SQLite APIs, those postfixed with "16" return
       
  2769 ** UTF-16 encoded strings, the other functions return UTF-8. {END}
       
  2770 **
       
  2771 ** These APIs are only available if the library was compiled with the
       
  2772 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
       
  2773 **
       
  2774 ** {A13751}
       
  2775 ** If two or more threads call one or more of these routines against the same
       
  2776 ** prepared statement and column at the same time then the results are
       
  2777 ** undefined.
       
  2778 **
       
  2779 ** Requirements:
       
  2780 ** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748]
       
  2781 **
       
  2782 ** If two or more threads call one or more
       
  2783 ** [sqlite3_column_database_name | column metadata interfaces]
       
  2784 ** for the same [prepared statement] and result column
       
  2785 ** at the same time then the results are undefined.
       
  2786 */
       
  2787 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
       
  2788 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
       
  2789 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
       
  2790 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
       
  2791 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
       
  2792 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
       
  2793 
       
  2794 /*
       
  2795 ** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700>
       
  2796 **
       
  2797 ** The first parameter is a [prepared statement].
       
  2798 ** If this statement is a [SELECT] statement and the Nth column of the
       
  2799 ** returned result set of that [SELECT] is a table column (not an
       
  2800 ** expression or subquery) then the declared type of the table
       
  2801 ** column is returned.  If the Nth column of the result set is an
       
  2802 ** expression or subquery, then a NULL pointer is returned.
       
  2803 ** The returned string is always UTF-8 encoded. {END}
       
  2804 **
       
  2805 ** For example, given the database schema:
       
  2806 **
       
  2807 ** CREATE TABLE t1(c1 VARIANT);
       
  2808 **
       
  2809 ** and the following statement to be compiled:
       
  2810 **
       
  2811 ** SELECT c1 + 1, c1 FROM t1;
       
  2812 **
       
  2813 ** this routine would return the string "VARIANT" for the second result
       
  2814 ** column (i==1), and a NULL pointer for the first result column (i==0).
       
  2815 **
       
  2816 ** SQLite uses dynamic run-time typing.  So just because a column
       
  2817 ** is declared to contain a particular type does not mean that the
       
  2818 ** data stored in that column is of the declared type.  SQLite is
       
  2819 ** strongly typed, but the typing is dynamic not static.  Type
       
  2820 ** is associated with individual values, not with the containers
       
  2821 ** used to hold those values.
       
  2822 **
       
  2823 ** Requirements:
       
  2824 ** [H13761] [H13762] [H13763]
       
  2825 */
       
  2826 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
       
  2827 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
       
  2828 
       
  2829 /*
       
  2830 ** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000>
       
  2831 **
       
  2832 ** After a [prepared statement] has been prepared using either
       
  2833 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
       
  2834 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
       
  2835 ** must be called one or more times to evaluate the statement.
       
  2836 **
       
  2837 ** The details of the behavior of the sqlite3_step() interface depend
       
  2838 ** on whether the statement was prepared using the newer "v2" interface
       
  2839 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
       
  2840 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
       
  2841 ** new "v2" interface is recommended for new applications but the legacy
       
  2842 ** interface will continue to be supported.
       
  2843 **
       
  2844 ** In the legacy interface, the return value will be either [SQLITE_BUSY],
       
  2845 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
       
  2846 ** With the "v2" interface, any of the other [result codes] or
       
  2847 ** [extended result codes] might be returned as well.
       
  2848 **
       
  2849 ** [SQLITE_BUSY] means that the database engine was unable to acquire the
       
  2850 ** database locks it needs to do its job.  If the statement is a [COMMIT]
       
  2851 ** or occurs outside of an explicit transaction, then you can retry the
       
  2852 ** statement.  If the statement is not a [COMMIT] and occurs within a
       
  2853 ** explicit transaction then you should rollback the transaction before
       
  2854 ** continuing.
       
  2855 **
       
  2856 ** [SQLITE_DONE] means that the statement has finished executing
       
  2857 ** successfully.  sqlite3_step() should not be called again on this virtual
       
  2858 ** machine without first calling [sqlite3_reset()] to reset the virtual
       
  2859 ** machine back to its initial state.
       
  2860 **
       
  2861 ** If the SQL statement being executed returns any data, then [SQLITE_ROW]
       
  2862 ** is returned each time a new row of data is ready for processing by the
       
  2863 ** caller. The values may be accessed using the [column access functions].
       
  2864 ** sqlite3_step() is called again to retrieve the next row of data.
       
  2865 **
       
  2866 ** [SQLITE_ERROR] means that a run-time error (such as a constraint
       
  2867 ** violation) has occurred.  sqlite3_step() should not be called again on
       
  2868 ** the VM. More information may be found by calling [sqlite3_errmsg()].
       
  2869 ** With the legacy interface, a more specific error code (for example,
       
  2870 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
       
  2871 ** can be obtained by calling [sqlite3_reset()] on the
       
  2872 ** [prepared statement].  In the "v2" interface,
       
  2873 ** the more specific error code is returned directly by sqlite3_step().
       
  2874 **
       
  2875 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
       
  2876 ** Perhaps it was called on a [prepared statement] that has
       
  2877 ** already been [sqlite3_finalize | finalized] or on one that had
       
  2878 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
       
  2879 ** be the case that the same database connection is being used by two or
       
  2880 ** more threads at the same moment in time.
       
  2881 **
       
  2882 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
       
  2883 ** API always returns a generic error code, [SQLITE_ERROR], following any
       
  2884 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
       
  2885 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
       
  2886 ** specific [error codes] that better describes the error.
       
  2887 ** We admit that this is a goofy design.  The problem has been fixed
       
  2888 ** with the "v2" interface.  If you prepare all of your SQL statements
       
  2889 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
       
  2890 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
       
  2891 ** then the more specific [error codes] are returned directly
       
  2892 ** by sqlite3_step().  The use of the "v2" interface is recommended.
       
  2893 **
       
  2894 ** Requirements:
       
  2895 ** [H13202] [H15304] [H15306] [H15308] [H15310]
       
  2896 */
       
  2897 SQLITE_API int sqlite3_step(sqlite3_stmt*);
       
  2898 
       
  2899 /*
       
  2900 ** CAPI3REF: Number of columns in a result set {H13770} <S10700>
       
  2901 **
       
  2902 ** Returns the number of values in the current row of the result set.
       
  2903 **
       
  2904 ** Requirements:
       
  2905 ** [H13771] [H13772]
       
  2906 */
       
  2907 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
       
  2908 
       
  2909 /*
       
  2910 ** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120>
       
  2911 ** KEYWORDS: SQLITE_TEXT
       
  2912 **
       
  2913 ** {H10266} Every value in SQLite has one of five fundamental datatypes:
       
  2914 **
       
  2915 ** <ul>
       
  2916 ** <li> 64-bit signed integer
       
  2917 ** <li> 64-bit IEEE floating point number
       
  2918 ** <li> string
       
  2919 ** <li> BLOB
       
  2920 ** <li> NULL
       
  2921 ** </ul> {END}
       
  2922 **
       
  2923 ** These constants are codes for each of those types.
       
  2924 **
       
  2925 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
       
  2926 ** for a completely different meaning.  Software that links against both
       
  2927 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
       
  2928 ** SQLITE_TEXT.
       
  2929 */
       
  2930 #define SQLITE_INTEGER  1
       
  2931 #define SQLITE_FLOAT    2
       
  2932 #define SQLITE_BLOB     4
       
  2933 #define SQLITE_NULL     5
       
  2934 #ifdef SQLITE_TEXT
       
  2935 # undef SQLITE_TEXT
       
  2936 #else
       
  2937 # define SQLITE_TEXT     3
       
  2938 #endif
       
  2939 #define SQLITE3_TEXT     3
       
  2940 
       
  2941 /*
       
  2942 ** CAPI3REF: Result Values From A Query {H13800} <S10700>
       
  2943 ** KEYWORDS: {column access functions}
       
  2944 **
       
  2945 ** These routines form the "result set query" interface.
       
  2946 **
       
  2947 ** These routines return information about a single column of the current
       
  2948 ** result row of a query.  In every case the first argument is a pointer
       
  2949 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
       
  2950 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
       
  2951 ** and the second argument is the index of the column for which information
       
  2952 ** should be returned.  The leftmost column of the result set has the index 0.
       
  2953 **
       
  2954 ** If the SQL statement does not currently point to a valid row, or if the
       
  2955 ** column index is out of range, the result is undefined.
       
  2956 ** These routines may only be called when the most recent call to
       
  2957 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
       
  2958 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
       
  2959 ** If any of these routines are called after [sqlite3_reset()] or
       
  2960 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
       
  2961 ** something other than [SQLITE_ROW], the results are undefined.
       
  2962 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
       
  2963 ** are called from a different thread while any of these routines
       
  2964 ** are pending, then the results are undefined.
       
  2965 **
       
  2966 ** The sqlite3_column_type() routine returns the
       
  2967 ** [SQLITE_INTEGER | datatype code] for the initial data type
       
  2968 ** of the result column.  The returned value is one of [SQLITE_INTEGER],
       
  2969 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
       
  2970 ** returned by sqlite3_column_type() is only meaningful if no type
       
  2971 ** conversions have occurred as described below.  After a type conversion,
       
  2972 ** the value returned by sqlite3_column_type() is undefined.  Future
       
  2973 ** versions of SQLite may change the behavior of sqlite3_column_type()
       
  2974 ** following a type conversion.
       
  2975 **
       
  2976 ** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
       
  2977 ** routine returns the number of bytes in that BLOB or string.
       
  2978 ** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
       
  2979 ** the string to UTF-8 and then returns the number of bytes.
       
  2980 ** If the result is a numeric value then sqlite3_column_bytes() uses
       
  2981 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
       
  2982 ** the number of bytes in that string.
       
  2983 ** The value returned does not include the zero terminator at the end
       
  2984 ** of the string.  For clarity: the value returned is the number of
       
  2985 ** bytes in the string, not the number of characters.
       
  2986 **
       
  2987 ** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
       
  2988 ** even empty strings, are always zero terminated.  The return
       
  2989 ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary
       
  2990 ** pointer, possibly even a NULL pointer.
       
  2991 **
       
  2992 ** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
       
  2993 ** but leaves the result in UTF-16 in native byte order instead of UTF-8.
       
  2994 ** The zero terminator is not included in this count.
       
  2995 **
       
  2996 ** The object returned by [sqlite3_column_value()] is an
       
  2997 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
       
  2998 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
       
  2999 ** If the [unprotected sqlite3_value] object returned by
       
  3000 ** [sqlite3_column_value()] is used in any other way, including calls
       
  3001 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
       
  3002 ** or [sqlite3_value_bytes()], then the behavior is undefined.
       
  3003 **
       
  3004 ** These routines attempt to convert the value where appropriate.  For
       
  3005 ** example, if the internal representation is FLOAT and a text result
       
  3006 ** is requested, [sqlite3_snprintf()] is used internally to perform the
       
  3007 ** conversion automatically.  The following table details the conversions
       
  3008 ** that are applied:
       
  3009 **
       
  3010 ** <blockquote>
       
  3011 ** <table border="1">
       
  3012 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
       
  3013 **
       
  3014 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
       
  3015 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
       
  3016 ** <tr><td>  NULL    <td>   TEXT    <td> Result is NULL pointer
       
  3017 ** <tr><td>  NULL    <td>   BLOB    <td> Result is NULL pointer
       
  3018 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
       
  3019 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
       
  3020 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
       
  3021 ** <tr><td>  FLOAT   <td> INTEGER   <td> Convert from float to integer
       
  3022 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
       
  3023 ** <tr><td>  FLOAT   <td>   BLOB    <td> Same as FLOAT->TEXT
       
  3024 ** <tr><td>  TEXT    <td> INTEGER   <td> Use atoi()
       
  3025 ** <tr><td>  TEXT    <td>  FLOAT    <td> Use atof()
       
  3026 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
       
  3027 ** <tr><td>  BLOB    <td> INTEGER   <td> Convert to TEXT then use atoi()
       
  3028 ** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
       
  3029 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
       
  3030 ** </table>
       
  3031 ** </blockquote>
       
  3032 **
       
  3033 ** The table above makes reference to standard C library functions atoi()
       
  3034 ** and atof().  SQLite does not really use these functions.  It has its
       
  3035 ** own equivalent internal routines.  The atoi() and atof() names are
       
  3036 ** used in the table for brevity and because they are familiar to most
       
  3037 ** C programmers.
       
  3038 **
       
  3039 ** Note that when type conversions occur, pointers returned by prior
       
  3040 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
       
  3041 ** sqlite3_column_text16() may be invalidated.
       
  3042 ** Type conversions and pointer invalidations might occur
       
  3043 ** in the following cases:
       
  3044 **
       
  3045 ** <ul>
       
  3046 ** <li> The initial content is a BLOB and sqlite3_column_text() or
       
  3047 **      sqlite3_column_text16() is called.  A zero-terminator might
       
  3048 **      need to be added to the string.</li>
       
  3049 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
       
  3050 **      sqlite3_column_text16() is called.  The content must be converted
       
  3051 **      to UTF-16.</li>
       
  3052 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
       
  3053 **      sqlite3_column_text() is called.  The content must be converted
       
  3054 **      to UTF-8.</li>
       
  3055 ** </ul>
       
  3056 **
       
  3057 ** Conversions between UTF-16be and UTF-16le are always done in place and do
       
  3058 ** not invalidate a prior pointer, though of course the content of the buffer
       
  3059 ** that the prior pointer points to will have been modified.  Other kinds
       
  3060 ** of conversion are done in place when it is possible, but sometimes they
       
  3061 ** are not possible and in those cases prior pointers are invalidated.
       
  3062 **
       
  3063 ** The safest and easiest to remember policy is to invoke these routines
       
  3064 ** in one of the following ways:
       
  3065 **
       
  3066 ** <ul>
       
  3067 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
       
  3068 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
       
  3069 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
       
  3070 ** </ul>
       
  3071 **
       
  3072 ** In other words, you should call sqlite3_column_text(),
       
  3073 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
       
  3074 ** into the desired format, then invoke sqlite3_column_bytes() or
       
  3075 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
       
  3076 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
       
  3077 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
       
  3078 ** with calls to sqlite3_column_bytes().
       
  3079 **
       
  3080 ** The pointers returned are valid until a type conversion occurs as
       
  3081 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
       
  3082 ** [sqlite3_finalize()] is called.  The memory space used to hold strings
       
  3083 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
       
  3084 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
       
  3085 ** [sqlite3_free()].
       
  3086 **
       
  3087 ** If a memory allocation error occurs during the evaluation of any
       
  3088 ** of these routines, a default value is returned.  The default value
       
  3089 ** is either the integer 0, the floating point number 0.0, or a NULL
       
  3090 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
       
  3091 ** [SQLITE_NOMEM].
       
  3092 **
       
  3093 ** Requirements:
       
  3094 ** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824]
       
  3095 ** [H13827] [H13830]
       
  3096 */
       
  3097 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
       
  3098 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
       
  3099 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
       
  3100 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
       
  3101 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
       
  3102 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
       
  3103 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
       
  3104 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
       
  3105 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
       
  3106 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
       
  3107 
       
  3108 /*
       
  3109 ** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100>
       
  3110 **
       
  3111 ** The sqlite3_finalize() function is called to delete a [prepared statement].
       
  3112 ** If the statement was executed successfully or not executed at all, then
       
  3113 ** SQLITE_OK is returned. If execution of the statement failed then an
       
  3114 ** [error code] or [extended error code] is returned.
       
  3115 **
       
  3116 ** This routine can be called at any point during the execution of the
       
  3117 ** [prepared statement].  If the virtual machine has not
       
  3118 ** completed execution when this routine is called, that is like
       
  3119 ** encountering an error or an [sqlite3_interrupt | interrupt].
       
  3120 ** Incomplete updates may be rolled back and transactions canceled,
       
  3121 ** depending on the circumstances, and the
       
  3122 ** [error code] returned will be [SQLITE_ABORT].
       
  3123 **
       
  3124 ** Requirements:
       
  3125 ** [H11302] [H11304]
       
  3126 */
       
  3127 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
       
  3128 
       
  3129 /*
       
  3130 ** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300>
       
  3131 **
       
  3132 ** The sqlite3_reset() function is called to reset a [prepared statement]
       
  3133 ** object back to its initial state, ready to be re-executed.
       
  3134 ** Any SQL statement variables that had values bound to them using
       
  3135 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
       
  3136 ** Use [sqlite3_clear_bindings()] to reset the bindings.
       
  3137 **
       
  3138 ** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
       
  3139 **          back to the beginning of its program.
       
  3140 **
       
  3141 ** {H11334} If the most recent call to [sqlite3_step(S)] for the
       
  3142 **          [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
       
  3143 **          or if [sqlite3_step(S)] has never before been called on S,
       
  3144 **          then [sqlite3_reset(S)] returns [SQLITE_OK].
       
  3145 **
       
  3146 ** {H11336} If the most recent call to [sqlite3_step(S)] for the
       
  3147 **          [prepared statement] S indicated an error, then
       
  3148 **          [sqlite3_reset(S)] returns an appropriate [error code].
       
  3149 **
       
  3150 ** {H11338} The [sqlite3_reset(S)] interface does not change the values
       
  3151 **          of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
       
  3152 */
       
  3153 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
       
  3154 
       
  3155 /*
       
  3156 ** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200>
       
  3157 ** KEYWORDS: {function creation routines}
       
  3158 ** KEYWORDS: {application-defined SQL function}
       
  3159 ** KEYWORDS: {application-defined SQL functions}
       
  3160 **
       
  3161 ** These two functions (collectively known as "function creation routines")
       
  3162 ** are used to add SQL functions or aggregates or to redefine the behavior
       
  3163 ** of existing SQL functions or aggregates.  The only difference between the
       
  3164 ** two is that the second parameter, the name of the (scalar) function or
       
  3165 ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16
       
  3166 ** for sqlite3_create_function16().
       
  3167 **
       
  3168 ** The first parameter is the [database connection] to which the SQL
       
  3169 ** function is to be added.  If a single program uses more than one database
       
  3170 ** connection internally, then SQL functions must be added individually to
       
  3171 ** each database connection.
       
  3172 **
       
  3173 ** The second parameter is the name of the SQL function to be created or
       
  3174 ** redefined.  The length of the name is limited to 255 bytes, exclusive of
       
  3175 ** the zero-terminator.  Note that the name length limit is in bytes, not
       
  3176 ** characters.  Any attempt to create a function with a longer name
       
  3177 ** will result in [SQLITE_ERROR] being returned.
       
  3178 **
       
  3179 ** The third parameter (nArg)
       
  3180 ** is the number of arguments that the SQL function or
       
  3181 ** aggregate takes. If this parameter is -1, then the SQL function or
       
  3182 ** aggregate may take any number of arguments between 0 and the limit
       
  3183 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
       
  3184 ** parameter is less than -1 or greater than 127 then the behavior is
       
  3185 ** undefined.
       
  3186 **
       
  3187 ** The fourth parameter, eTextRep, specifies what
       
  3188 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
       
  3189 ** its parameters.  Any SQL function implementation should be able to work
       
  3190 ** work with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
       
  3191 ** more efficient with one encoding than another.  An application may
       
  3192 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
       
  3193 ** times with the same function but with different values of eTextRep.
       
  3194 ** When multiple implementations of the same function are available, SQLite
       
  3195 ** will pick the one that involves the least amount of data conversion.
       
  3196 ** If there is only a single implementation which does not care what text
       
  3197 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
       
  3198 **
       
  3199 ** The fifth parameter is an arbitrary pointer.  The implementation of the
       
  3200 ** function can gain access to this pointer using [sqlite3_user_data()].
       
  3201 **
       
  3202 ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
       
  3203 ** pointers to C-language functions that implement the SQL function or
       
  3204 ** aggregate. A scalar SQL function requires an implementation of the xFunc
       
  3205 ** callback only, NULL pointers should be passed as the xStep and xFinal
       
  3206 ** parameters. An aggregate SQL function requires an implementation of xStep
       
  3207 ** and xFinal and NULL should be passed for xFunc. To delete an existing
       
  3208 ** SQL function or aggregate, pass NULL for all three function callbacks.
       
  3209 **
       
  3210 ** It is permitted to register multiple implementations of the same
       
  3211 ** functions with the same name but with either differing numbers of
       
  3212 ** arguments or differing preferred text encodings.  SQLite will use
       
  3213 ** the implementation that most closely matches the way in which the
       
  3214 ** SQL function is used.  A function implementation with a non-negative
       
  3215 ** nArg parameter is a better match than a function implementation with
       
  3216 ** a negative nArg.  A function where the preferred text encoding
       
  3217 ** matches the database encoding is a better
       
  3218 ** match than a function where the encoding is different.  
       
  3219 ** A function where the encoding difference is between UTF16le and UTF16be
       
  3220 ** is a closer match than a function where the encoding difference is
       
  3221 ** between UTF8 and UTF16.
       
  3222 **
       
  3223 ** Built-in functions may be overloaded by new application-defined functions.
       
  3224 ** The first application-defined function with a given name overrides all
       
  3225 ** built-in functions in the same [database connection] with the same name.
       
  3226 ** Subsequent application-defined functions of the same name only override 
       
  3227 ** prior application-defined functions that are an exact match for the
       
  3228 ** number of parameters and preferred encoding.
       
  3229 **
       
  3230 ** An application-defined function is permitted to call other
       
  3231 ** SQLite interfaces.  However, such calls must not
       
  3232 ** close the database connection nor finalize or reset the prepared
       
  3233 ** statement in which the function is running.
       
  3234 **
       
  3235 ** Requirements:
       
  3236 ** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16127]
       
  3237 ** [H16130] [H16133] [H16136] [H16139] [H16142]
       
  3238 */
       
  3239 SQLITE_API int sqlite3_create_function(
       
  3240   sqlite3 *db,
       
  3241   const char *zFunctionName,
       
  3242   int nArg,
       
  3243   int eTextRep,
       
  3244   void *pApp,
       
  3245   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3246   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3247   void (*xFinal)(sqlite3_context*)
       
  3248 );
       
  3249 SQLITE_API int sqlite3_create_function16(
       
  3250   sqlite3 *db,
       
  3251   const void *zFunctionName,
       
  3252   int nArg,
       
  3253   int eTextRep,
       
  3254   void *pApp,
       
  3255   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3256   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3257   void (*xFinal)(sqlite3_context*)
       
  3258 );
       
  3259 
       
  3260 /*
       
  3261 ** CAPI3REF: Text Encodings {H10267} <S50200> <H16100>
       
  3262 **
       
  3263 ** These constant define integer codes that represent the various
       
  3264 ** text encodings supported by SQLite.
       
  3265 */
       
  3266 #define SQLITE_UTF8           1
       
  3267 #define SQLITE_UTF16LE        2
       
  3268 #define SQLITE_UTF16BE        3
       
  3269 #define SQLITE_UTF16          4    /* Use native byte order */
       
  3270 #define SQLITE_ANY            5    /* sqlite3_create_function only */
       
  3271 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
       
  3272 
       
  3273 /*
       
  3274 ** CAPI3REF: Deprecated Functions
       
  3275 ** DEPRECATED
       
  3276 **
       
  3277 ** These functions are [deprecated].  In order to maintain
       
  3278 ** backwards compatibility with older code, these functions continue 
       
  3279 ** to be supported.  However, new applications should avoid
       
  3280 ** the use of these functions.  To help encourage people to avoid
       
  3281 ** using these functions, we are not going to tell you what they do.
       
  3282 */
       
  3283 #ifndef SQLITE_OMIT_DEPRECATED
       
  3284 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
       
  3285 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
       
  3286 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
       
  3287 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
       
  3288 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
       
  3289 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
       
  3290 #endif
       
  3291 
       
  3292 /*
       
  3293 ** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200>
       
  3294 **
       
  3295 ** The C-language implementation of SQL functions and aggregates uses
       
  3296 ** this set of interface routines to access the parameter values on
       
  3297 ** the function or aggregate.
       
  3298 **
       
  3299 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
       
  3300 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
       
  3301 ** define callbacks that implement the SQL functions and aggregates.
       
  3302 ** The 4th parameter to these callbacks is an array of pointers to
       
  3303 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
       
  3304 ** each parameter to the SQL function.  These routines are used to
       
  3305 ** extract values from the [sqlite3_value] objects.
       
  3306 **
       
  3307 ** These routines work only with [protected sqlite3_value] objects.
       
  3308 ** Any attempt to use these routines on an [unprotected sqlite3_value]
       
  3309 ** object results in undefined behavior.
       
  3310 **
       
  3311 ** These routines work just like the corresponding [column access functions]
       
  3312 ** except that  these routines take a single [protected sqlite3_value] object
       
  3313 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
       
  3314 **
       
  3315 ** The sqlite3_value_text16() interface extracts a UTF-16 string
       
  3316 ** in the native byte-order of the host machine.  The
       
  3317 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
       
  3318 ** extract UTF-16 strings as big-endian and little-endian respectively.
       
  3319 **
       
  3320 ** The sqlite3_value_numeric_type() interface attempts to apply
       
  3321 ** numeric affinity to the value.  This means that an attempt is
       
  3322 ** made to convert the value to an integer or floating point.  If
       
  3323 ** such a conversion is possible without loss of information (in other
       
  3324 ** words, if the value is a string that looks like a number)
       
  3325 ** then the conversion is performed.  Otherwise no conversion occurs.
       
  3326 ** The [SQLITE_INTEGER | datatype] after conversion is returned.
       
  3327 **
       
  3328 ** Please pay particular attention to the fact that the pointer returned
       
  3329 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
       
  3330 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
       
  3331 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
       
  3332 ** or [sqlite3_value_text16()].
       
  3333 **
       
  3334 ** These routines must be called from the same thread as
       
  3335 ** the SQL function that supplied the [sqlite3_value*] parameters.
       
  3336 **
       
  3337 ** Requirements:
       
  3338 ** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124]
       
  3339 ** [H15127] [H15130] [H15133] [H15136]
       
  3340 */
       
  3341 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
       
  3342 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
       
  3343 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
       
  3344 SQLITE_API double sqlite3_value_double(sqlite3_value*);
       
  3345 SQLITE_API int sqlite3_value_int(sqlite3_value*);
       
  3346 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
       
  3347 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
       
  3348 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
       
  3349 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
       
  3350 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
       
  3351 SQLITE_API int sqlite3_value_type(sqlite3_value*);
       
  3352 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
       
  3353 
       
  3354 /*
       
  3355 ** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200>
       
  3356 **
       
  3357 ** The implementation of aggregate SQL functions use this routine to allocate
       
  3358 ** a structure for storing their state.
       
  3359 **
       
  3360 ** The first time the sqlite3_aggregate_context() routine is called for a
       
  3361 ** particular aggregate, SQLite allocates nBytes of memory, zeroes out that
       
  3362 ** memory, and returns a pointer to it. On second and subsequent calls to
       
  3363 ** sqlite3_aggregate_context() for the same aggregate function index,
       
  3364 ** the same buffer is returned. The implementation of the aggregate can use
       
  3365 ** the returned buffer to accumulate data.
       
  3366 **
       
  3367 ** SQLite automatically frees the allocated buffer when the aggregate
       
  3368 ** query concludes.
       
  3369 **
       
  3370 ** The first parameter should be a copy of the
       
  3371 ** [sqlite3_context | SQL function context] that is the first parameter
       
  3372 ** to the callback routine that implements the aggregate function.
       
  3373 **
       
  3374 ** This routine must be called from the same thread in which
       
  3375 ** the aggregate SQL function is running.
       
  3376 **
       
  3377 ** Requirements:
       
  3378 ** [H16211] [H16213] [H16215] [H16217]
       
  3379 */
       
  3380 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
       
  3381 
       
  3382 /*
       
  3383 ** CAPI3REF: User Data For Functions {H16240} <S20200>
       
  3384 **
       
  3385 ** The sqlite3_user_data() interface returns a copy of
       
  3386 ** the pointer that was the pUserData parameter (the 5th parameter)
       
  3387 ** of the [sqlite3_create_function()]
       
  3388 ** and [sqlite3_create_function16()] routines that originally
       
  3389 ** registered the application defined function. {END}
       
  3390 **
       
  3391 ** This routine must be called from the same thread in which
       
  3392 ** the application-defined function is running.
       
  3393 **
       
  3394 ** Requirements:
       
  3395 ** [H16243]
       
  3396 */
       
  3397 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
       
  3398 
       
  3399 /*
       
  3400 ** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200>
       
  3401 **
       
  3402 ** The sqlite3_context_db_handle() interface returns a copy of
       
  3403 ** the pointer to the [database connection] (the 1st parameter)
       
  3404 ** of the [sqlite3_create_function()]
       
  3405 ** and [sqlite3_create_function16()] routines that originally
       
  3406 ** registered the application defined function.
       
  3407 **
       
  3408 ** Requirements:
       
  3409 ** [H16253]
       
  3410 */
       
  3411 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
       
  3412 
       
  3413 /*
       
  3414 ** CAPI3REF: Function Auxiliary Data {H16270} <S20200>
       
  3415 **
       
  3416 ** The following two functions may be used by scalar SQL functions to
       
  3417 ** associate metadata with argument values. If the same value is passed to
       
  3418 ** multiple invocations of the same SQL function during query execution, under
       
  3419 ** some circumstances the associated metadata may be preserved. This may
       
  3420 ** be used, for example, to add a regular-expression matching scalar
       
  3421 ** function. The compiled version of the regular expression is stored as
       
  3422 ** metadata associated with the SQL value passed as the regular expression
       
  3423 ** pattern.  The compiled regular expression can be reused on multiple
       
  3424 ** invocations of the same function so that the original pattern string
       
  3425 ** does not need to be recompiled on each invocation.
       
  3426 **
       
  3427 ** The sqlite3_get_auxdata() interface returns a pointer to the metadata
       
  3428 ** associated by the sqlite3_set_auxdata() function with the Nth argument
       
  3429 ** value to the application-defined function. If no metadata has been ever
       
  3430 ** been set for the Nth argument of the function, or if the corresponding
       
  3431 ** function parameter has changed since the meta-data was set,
       
  3432 ** then sqlite3_get_auxdata() returns a NULL pointer.
       
  3433 **
       
  3434 ** The sqlite3_set_auxdata() interface saves the metadata
       
  3435 ** pointed to by its 3rd parameter as the metadata for the N-th
       
  3436 ** argument of the application-defined function.  Subsequent
       
  3437 ** calls to sqlite3_get_auxdata() might return this data, if it has
       
  3438 ** not been destroyed.
       
  3439 ** If it is not NULL, SQLite will invoke the destructor
       
  3440 ** function given by the 4th parameter to sqlite3_set_auxdata() on
       
  3441 ** the metadata when the corresponding function parameter changes
       
  3442 ** or when the SQL statement completes, whichever comes first.
       
  3443 **
       
  3444 ** SQLite is free to call the destructor and drop metadata on any
       
  3445 ** parameter of any function at any time.  The only guarantee is that
       
  3446 ** the destructor will be called before the metadata is dropped.
       
  3447 **
       
  3448 ** In practice, metadata is preserved between function calls for
       
  3449 ** expressions that are constant at compile time. This includes literal
       
  3450 ** values and SQL variables.
       
  3451 **
       
  3452 ** These routines must be called from the same thread in which
       
  3453 ** the SQL function is running.
       
  3454 **
       
  3455 ** Requirements:
       
  3456 ** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279]
       
  3457 */
       
  3458 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
       
  3459 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
       
  3460 
       
  3461 
       
  3462 /*
       
  3463 ** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100>
       
  3464 **
       
  3465 ** These are special values for the destructor that is passed in as the
       
  3466 ** final argument to routines like [sqlite3_result_blob()].  If the destructor
       
  3467 ** argument is SQLITE_STATIC, it means that the content pointer is constant
       
  3468 ** and will never change.  It does not need to be destroyed.  The
       
  3469 ** SQLITE_TRANSIENT value means that the content will likely change in
       
  3470 ** the near future and that SQLite should make its own private copy of
       
  3471 ** the content before returning.
       
  3472 **
       
  3473 ** The typedef is necessary to work around problems in certain
       
  3474 ** C++ compilers.  See ticket #2191.
       
  3475 */
       
  3476 typedef void (*sqlite3_destructor_type)(void*);
       
  3477 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
       
  3478 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
       
  3479 
       
  3480 /*
       
  3481 ** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200>
       
  3482 **
       
  3483 ** These routines are used by the xFunc or xFinal callbacks that
       
  3484 ** implement SQL functions and aggregates.  See
       
  3485 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
       
  3486 ** for additional information.
       
  3487 **
       
  3488 ** These functions work very much like the [parameter binding] family of
       
  3489 ** functions used to bind values to host parameters in prepared statements.
       
  3490 ** Refer to the [SQL parameter] documentation for additional information.
       
  3491 **
       
  3492 ** The sqlite3_result_blob() interface sets the result from
       
  3493 ** an application-defined function to be the BLOB whose content is pointed
       
  3494 ** to by the second parameter and which is N bytes long where N is the
       
  3495 ** third parameter.
       
  3496 **
       
  3497 ** The sqlite3_result_zeroblob() interfaces set the result of
       
  3498 ** the application-defined function to be a BLOB containing all zero
       
  3499 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
       
  3500 **
       
  3501 ** The sqlite3_result_double() interface sets the result from
       
  3502 ** an application-defined function to be a floating point value specified
       
  3503 ** by its 2nd argument.
       
  3504 **
       
  3505 ** The sqlite3_result_error() and sqlite3_result_error16() functions
       
  3506 ** cause the implemented SQL function to throw an exception.
       
  3507 ** SQLite uses the string pointed to by the
       
  3508 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
       
  3509 ** as the text of an error message.  SQLite interprets the error
       
  3510 ** message string from sqlite3_result_error() as UTF-8. SQLite
       
  3511 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
       
  3512 ** byte order.  If the third parameter to sqlite3_result_error()
       
  3513 ** or sqlite3_result_error16() is negative then SQLite takes as the error
       
  3514 ** message all text up through the first zero character.
       
  3515 ** If the third parameter to sqlite3_result_error() or
       
  3516 ** sqlite3_result_error16() is non-negative then SQLite takes that many
       
  3517 ** bytes (not characters) from the 2nd parameter as the error message.
       
  3518 ** The sqlite3_result_error() and sqlite3_result_error16()
       
  3519 ** routines make a private copy of the error message text before
       
  3520 ** they return.  Hence, the calling function can deallocate or
       
  3521 ** modify the text after they return without harm.
       
  3522 ** The sqlite3_result_error_code() function changes the error code
       
  3523 ** returned by SQLite as a result of an error in a function.  By default,
       
  3524 ** the error code is SQLITE_ERROR.  A subsequent call to sqlite3_result_error()
       
  3525 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
       
  3526 **
       
  3527 ** The sqlite3_result_toobig() interface causes SQLite to throw an error
       
  3528 ** indicating that a string or BLOB is to long to represent.
       
  3529 **
       
  3530 ** The sqlite3_result_nomem() interface causes SQLite to throw an error
       
  3531 ** indicating that a memory allocation failed.
       
  3532 **
       
  3533 ** The sqlite3_result_int() interface sets the return value
       
  3534 ** of the application-defined function to be the 32-bit signed integer
       
  3535 ** value given in the 2nd argument.
       
  3536 ** The sqlite3_result_int64() interface sets the return value
       
  3537 ** of the application-defined function to be the 64-bit signed integer
       
  3538 ** value given in the 2nd argument.
       
  3539 **
       
  3540 ** The sqlite3_result_null() interface sets the return value
       
  3541 ** of the application-defined function to be NULL.
       
  3542 **
       
  3543 ** The sqlite3_result_text(), sqlite3_result_text16(),
       
  3544 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
       
  3545 ** set the return value of the application-defined function to be
       
  3546 ** a text string which is represented as UTF-8, UTF-16 native byte order,
       
  3547 ** UTF-16 little endian, or UTF-16 big endian, respectively.
       
  3548 ** SQLite takes the text result from the application from
       
  3549 ** the 2nd parameter of the sqlite3_result_text* interfaces.
       
  3550 ** If the 3rd parameter to the sqlite3_result_text* interfaces
       
  3551 ** is negative, then SQLite takes result text from the 2nd parameter
       
  3552 ** through the first zero character.
       
  3553 ** If the 3rd parameter to the sqlite3_result_text* interfaces
       
  3554 ** is non-negative, then as many bytes (not characters) of the text
       
  3555 ** pointed to by the 2nd parameter are taken as the application-defined
       
  3556 ** function result.
       
  3557 ** If the 4th parameter to the sqlite3_result_text* interfaces
       
  3558 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
       
  3559 ** function as the destructor on the text or BLOB result when it has
       
  3560 ** finished using that result.
       
  3561 ** If the 4th parameter to the sqlite3_result_text* interfaces or to
       
  3562 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
       
  3563 ** assumes that the text or BLOB result is in constant space and does not
       
  3564 ** copy the content of the parameter nor call a destructor on the content
       
  3565 ** when it has finished using that result.
       
  3566 ** If the 4th parameter to the sqlite3_result_text* interfaces
       
  3567 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
       
  3568 ** then SQLite makes a copy of the result into space obtained from
       
  3569 ** from [sqlite3_malloc()] before it returns.
       
  3570 **
       
  3571 ** The sqlite3_result_value() interface sets the result of
       
  3572 ** the application-defined function to be a copy the
       
  3573 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  The
       
  3574 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
       
  3575 ** so that the [sqlite3_value] specified in the parameter may change or
       
  3576 ** be deallocated after sqlite3_result_value() returns without harm.
       
  3577 ** A [protected sqlite3_value] object may always be used where an
       
  3578 ** [unprotected sqlite3_value] object is required, so either
       
  3579 ** kind of [sqlite3_value] object can be used with this interface.
       
  3580 **
       
  3581 ** If these routines are called from within the different thread
       
  3582 ** than the one containing the application-defined function that received
       
  3583 ** the [sqlite3_context] pointer, the results are undefined.
       
  3584 **
       
  3585 ** Requirements:
       
  3586 ** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424]
       
  3587 ** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448]
       
  3588 ** [H16451] [H16454] [H16457] [H16460] [H16463]
       
  3589 */
       
  3590 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
       
  3591 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
       
  3592 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
       
  3593 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
       
  3594 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
       
  3595 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
       
  3596 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
       
  3597 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
       
  3598 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
       
  3599 SQLITE_API void sqlite3_result_null(sqlite3_context*);
       
  3600 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
       
  3601 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
       
  3602 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
       
  3603 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
       
  3604 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
       
  3605 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
       
  3606 
       
  3607 /*
       
  3608 ** CAPI3REF: Define New Collating Sequences {H16600} <S20300>
       
  3609 **
       
  3610 ** These functions are used to add new collation sequences to the
       
  3611 ** [database connection] specified as the first argument.
       
  3612 **
       
  3613 ** The name of the new collation sequence is specified as a UTF-8 string
       
  3614 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
       
  3615 ** and a UTF-16 string for sqlite3_create_collation16(). In all cases
       
  3616 ** the name is passed as the second function argument.
       
  3617 **
       
  3618 ** The third argument may be one of the constants [SQLITE_UTF8],
       
  3619 ** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied
       
  3620 ** routine expects to be passed pointers to strings encoded using UTF-8,
       
  3621 ** UTF-16 little-endian, or UTF-16 big-endian, respectively. The
       
  3622 ** third argument might also be [SQLITE_UTF16] to indicate that the routine
       
  3623 ** expects pointers to be UTF-16 strings in the native byte order, or the
       
  3624 ** argument can be [SQLITE_UTF16_ALIGNED] if the
       
  3625 ** the routine expects pointers to 16-bit word aligned strings
       
  3626 ** of UTF-16 in the native byte order.
       
  3627 **
       
  3628 ** A pointer to the user supplied routine must be passed as the fifth
       
  3629 ** argument.  If it is NULL, this is the same as deleting the collation
       
  3630 ** sequence (so that SQLite cannot call it anymore).
       
  3631 ** Each time the application supplied function is invoked, it is passed
       
  3632 ** as its first parameter a copy of the void* passed as the fourth argument
       
  3633 ** to sqlite3_create_collation() or sqlite3_create_collation16().
       
  3634 **
       
  3635 ** The remaining arguments to the application-supplied routine are two strings,
       
  3636 ** each represented by a (length, data) pair and encoded in the encoding
       
  3637 ** that was passed as the third argument when the collation sequence was
       
  3638 ** registered. {END}  The application defined collation routine should
       
  3639 ** return negative, zero or positive if the first string is less than,
       
  3640 ** equal to, or greater than the second string. i.e. (STRING1 - STRING2).
       
  3641 **
       
  3642 ** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
       
  3643 ** except that it takes an extra argument which is a destructor for
       
  3644 ** the collation.  The destructor is called when the collation is
       
  3645 ** destroyed and is passed a copy of the fourth parameter void* pointer
       
  3646 ** of the sqlite3_create_collation_v2().
       
  3647 ** Collations are destroyed when they are overridden by later calls to the
       
  3648 ** collation creation functions or when the [database connection] is closed
       
  3649 ** using [sqlite3_close()].
       
  3650 **
       
  3651 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
       
  3652 **
       
  3653 ** Requirements:
       
  3654 ** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621]
       
  3655 ** [H16624] [H16627] [H16630]
       
  3656 */
       
  3657 SQLITE_API int sqlite3_create_collation(
       
  3658   sqlite3*, 
       
  3659   const char *zName, 
       
  3660   int eTextRep, 
       
  3661   void*,
       
  3662   int(*xCompare)(void*,int,const void*,int,const void*)
       
  3663 );
       
  3664 SQLITE_API int sqlite3_create_collation_v2(
       
  3665   sqlite3*, 
       
  3666   const char *zName, 
       
  3667   int eTextRep, 
       
  3668   void*,
       
  3669   int(*xCompare)(void*,int,const void*,int,const void*),
       
  3670   void(*xDestroy)(void*)
       
  3671 );
       
  3672 SQLITE_API int sqlite3_create_collation16(
       
  3673   sqlite3*, 
       
  3674   const void *zName,
       
  3675   int eTextRep, 
       
  3676   void*,
       
  3677   int(*xCompare)(void*,int,const void*,int,const void*)
       
  3678 );
       
  3679 
       
  3680 /*
       
  3681 ** CAPI3REF: Collation Needed Callbacks {H16700} <S20300>
       
  3682 **
       
  3683 ** To avoid having to register all collation sequences before a database
       
  3684 ** can be used, a single callback function may be registered with the
       
  3685 ** [database connection] to be called whenever an undefined collation
       
  3686 ** sequence is required.
       
  3687 **
       
  3688 ** If the function is registered using the sqlite3_collation_needed() API,
       
  3689 ** then it is passed the names of undefined collation sequences as strings
       
  3690 ** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used,
       
  3691 ** the names are passed as UTF-16 in machine native byte order.
       
  3692 ** A call to either function replaces any existing callback.
       
  3693 **
       
  3694 ** When the callback is invoked, the first argument passed is a copy
       
  3695 ** of the second argument to sqlite3_collation_needed() or
       
  3696 ** sqlite3_collation_needed16().  The second argument is the database
       
  3697 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
       
  3698 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
       
  3699 ** sequence function required.  The fourth parameter is the name of the
       
  3700 ** required collation sequence.
       
  3701 **
       
  3702 ** The callback function should register the desired collation using
       
  3703 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
       
  3704 ** [sqlite3_create_collation_v2()].
       
  3705 **
       
  3706 ** Requirements:
       
  3707 ** [H16702] [H16704] [H16706]
       
  3708 */
       
  3709 SQLITE_API int sqlite3_collation_needed(
       
  3710   sqlite3*, 
       
  3711   void*, 
       
  3712   void(*)(void*,sqlite3*,int eTextRep,const char*)
       
  3713 );
       
  3714 SQLITE_API int sqlite3_collation_needed16(
       
  3715   sqlite3*, 
       
  3716   void*,
       
  3717   void(*)(void*,sqlite3*,int eTextRep,const void*)
       
  3718 );
       
  3719 
       
  3720 /*
       
  3721 ** Specify the key for an encrypted database.  This routine should be
       
  3722 ** called right after sqlite3_open().
       
  3723 **
       
  3724 ** The code to implement this API is not available in the public release
       
  3725 ** of SQLite.
       
  3726 */
       
  3727 SQLITE_API int sqlite3_key(
       
  3728   sqlite3 *db,                   /* Database to be rekeyed */
       
  3729   const void *pKey, int nKey     /* The key */
       
  3730 );
       
  3731 
       
  3732 /*
       
  3733 ** Change the key on an open database.  If the current database is not
       
  3734 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
       
  3735 ** database is decrypted.
       
  3736 **
       
  3737 ** The code to implement this API is not available in the public release
       
  3738 ** of SQLite.
       
  3739 */
       
  3740 SQLITE_API int sqlite3_rekey(
       
  3741   sqlite3 *db,                   /* Database to be rekeyed */
       
  3742   const void *pKey, int nKey     /* The new key */
       
  3743 );
       
  3744 
       
  3745 /*
       
  3746 ** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410>
       
  3747 **
       
  3748 ** The sqlite3_sleep() function causes the current thread to suspend execution
       
  3749 ** for at least a number of milliseconds specified in its parameter.
       
  3750 **
       
  3751 ** If the operating system does not support sleep requests with
       
  3752 ** millisecond time resolution, then the time will be rounded up to
       
  3753 ** the nearest second. The number of milliseconds of sleep actually
       
  3754 ** requested from the operating system is returned.
       
  3755 **
       
  3756 ** SQLite implements this interface by calling the xSleep()
       
  3757 ** method of the default [sqlite3_vfs] object.
       
  3758 **
       
  3759 ** Requirements: [H10533] [H10536]
       
  3760 */
       
  3761 SQLITE_API int sqlite3_sleep(int);
       
  3762 
       
  3763 /*
       
  3764 ** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000>
       
  3765 **
       
  3766 ** If this global variable is made to point to a string which is
       
  3767 ** the name of a folder (a.k.a. directory), then all temporary files
       
  3768 ** created by SQLite will be placed in that directory.  If this variable
       
  3769 ** is a NULL pointer, then SQLite performs a search for an appropriate
       
  3770 ** temporary file directory.
       
  3771 **
       
  3772 ** It is not safe to read or modify this variable in more than one
       
  3773 ** thread at a time.  It is not safe to read or modify this variable
       
  3774 ** if a [database connection] is being used at the same time in a separate
       
  3775 ** thread.
       
  3776 ** It is intended that this variable be set once
       
  3777 ** as part of process initialization and before any SQLite interface
       
  3778 ** routines have been called and that this variable remain unchanged
       
  3779 ** thereafter.
       
  3780 **
       
  3781 ** The [temp_store_directory pragma] may modify this variable and cause
       
  3782 ** it to point to memory obtained from [sqlite3_malloc].  Furthermore,
       
  3783 ** the [temp_store_directory pragma] always assumes that any string
       
  3784 ** that this variable points to is held in memory obtained from 
       
  3785 ** [sqlite3_malloc] and the pragma may attempt to free that memory
       
  3786 ** using [sqlite3_free].
       
  3787 ** Hence, if this variable is modified directly, either it should be
       
  3788 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
       
  3789 ** or else the use of the [temp_store_directory pragma] should be avoided.
       
  3790 */
       
  3791 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
       
  3792 
       
  3793 /*
       
  3794 ** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200>
       
  3795 ** KEYWORDS: {autocommit mode}
       
  3796 **
       
  3797 ** The sqlite3_get_autocommit() interface returns non-zero or
       
  3798 ** zero if the given database connection is or is not in autocommit mode,
       
  3799 ** respectively.  Autocommit mode is on by default.
       
  3800 ** Autocommit mode is disabled by a [BEGIN] statement.
       
  3801 ** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
       
  3802 **
       
  3803 ** If certain kinds of errors occur on a statement within a multi-statement
       
  3804 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
       
  3805 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
       
  3806 ** transaction might be rolled back automatically.  The only way to
       
  3807 ** find out whether SQLite automatically rolled back the transaction after
       
  3808 ** an error is to use this function.
       
  3809 **
       
  3810 ** If another thread changes the autocommit status of the database
       
  3811 ** connection while this routine is running, then the return value
       
  3812 ** is undefined.
       
  3813 **
       
  3814 ** Requirements: [H12931] [H12932] [H12933] [H12934]
       
  3815 */
       
  3816 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
       
  3817 
       
  3818 /*
       
  3819 ** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600>
       
  3820 **
       
  3821 ** The sqlite3_db_handle interface returns the [database connection] handle
       
  3822 ** to which a [prepared statement] belongs.  The [database connection]
       
  3823 ** returned by sqlite3_db_handle is the same [database connection] that was the first argument
       
  3824 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
       
  3825 ** create the statement in the first place.
       
  3826 **
       
  3827 ** Requirements: [H13123]
       
  3828 */
       
  3829 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
       
  3830 
       
  3831 /*
       
  3832 ** CAPI3REF: Find the next prepared statement {H13140} <S60600>
       
  3833 **
       
  3834 ** This interface returns a pointer to the next [prepared statement] after
       
  3835 ** pStmt associated with the [database connection] pDb.  If pStmt is NULL
       
  3836 ** then this interface returns a pointer to the first prepared statement
       
  3837 ** associated with the database connection pDb.  If no prepared statement
       
  3838 ** satisfies the conditions of this routine, it returns NULL.
       
  3839 **
       
  3840 ** The [database connection] pointer D in a call to
       
  3841 ** [sqlite3_next_stmt(D,S)] must refer to an open database
       
  3842 ** connection and in particular must not be a NULL pointer.
       
  3843 **
       
  3844 ** Requirements: [H13143] [H13146] [H13149] [H13152]
       
  3845 */
       
  3846 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
       
  3847 
       
  3848 /*
       
  3849 ** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400>
       
  3850 **
       
  3851 ** The sqlite3_commit_hook() interface registers a callback
       
  3852 ** function to be invoked whenever a transaction is [COMMIT | committed].
       
  3853 ** Any callback set by a previous call to sqlite3_commit_hook()
       
  3854 ** for the same database connection is overridden.
       
  3855 ** The sqlite3_rollback_hook() interface registers a callback
       
  3856 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
       
  3857 ** Any callback set by a previous call to sqlite3_commit_hook()
       
  3858 ** for the same database connection is overridden.
       
  3859 ** The pArg argument is passed through to the callback.
       
  3860 ** If the callback on a commit hook function returns non-zero,
       
  3861 ** then the commit is converted into a rollback.
       
  3862 **
       
  3863 ** If another function was previously registered, its
       
  3864 ** pArg value is returned.  Otherwise NULL is returned.
       
  3865 **
       
  3866 ** The callback implementation must not do anything that will modify
       
  3867 ** the database connection that invoked the callback.  Any actions
       
  3868 ** to modify the database connection must be deferred until after the
       
  3869 ** completion of the [sqlite3_step()] call that triggered the commit
       
  3870 ** or rollback hook in the first place.
       
  3871 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  3872 ** database connections for the meaning of "modify" in this paragraph.
       
  3873 **
       
  3874 ** Registering a NULL function disables the callback.
       
  3875 **
       
  3876 ** When the commit hook callback routine returns zero, the [COMMIT]
       
  3877 ** operation is allowed to continue normally.  If the commit hook
       
  3878 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
       
  3879 ** The rollback hook is invoked on a rollback that results from a commit
       
  3880 ** hook returning non-zero, just as it would be with any other rollback.
       
  3881 **
       
  3882 ** For the purposes of this API, a transaction is said to have been
       
  3883 ** rolled back if an explicit "ROLLBACK" statement is executed, or
       
  3884 ** an error or constraint causes an implicit rollback to occur.
       
  3885 ** The rollback callback is not invoked if a transaction is
       
  3886 ** automatically rolled back because the database connection is closed.
       
  3887 ** The rollback callback is not invoked if a transaction is
       
  3888 ** rolled back because a commit callback returned non-zero.
       
  3889 ** <todo> Check on this </todo>
       
  3890 **
       
  3891 ** See also the [sqlite3_update_hook()] interface.
       
  3892 **
       
  3893 ** Requirements:
       
  3894 ** [H12951] [H12952] [H12953] [H12954] [H12955]
       
  3895 ** [H12961] [H12962] [H12963] [H12964]
       
  3896 */
       
  3897 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
       
  3898 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
       
  3899 
       
  3900 /*
       
  3901 ** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400>
       
  3902 **
       
  3903 ** The sqlite3_update_hook() interface registers a callback function
       
  3904 ** with the [database connection] identified by the first argument
       
  3905 ** to be invoked whenever a row is updated, inserted or deleted.
       
  3906 ** Any callback set by a previous call to this function
       
  3907 ** for the same database connection is overridden.
       
  3908 **
       
  3909 ** The second argument is a pointer to the function to invoke when a
       
  3910 ** row is updated, inserted or deleted.
       
  3911 ** The first argument to the callback is a copy of the third argument
       
  3912 ** to sqlite3_update_hook().
       
  3913 ** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
       
  3914 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
       
  3915 ** to be invoked.
       
  3916 ** The third and fourth arguments to the callback contain pointers to the
       
  3917 ** database and table name containing the affected row.
       
  3918 ** The final callback parameter is the [rowid] of the row.
       
  3919 ** In the case of an update, this is the [rowid] after the update takes place.
       
  3920 **
       
  3921 ** The update hook is not invoked when internal system tables are
       
  3922 ** modified (i.e. sqlite_master and sqlite_sequence).
       
  3923 **
       
  3924 ** In the current implementation, the update hook
       
  3925 ** is not invoked when duplication rows are deleted because of an
       
  3926 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  Nor is the update hook
       
  3927 ** invoked when rows are deleted using the [truncate optimization].
       
  3928 ** The exceptions defined in this paragraph might change in a future
       
  3929 ** release of SQLite.
       
  3930 **
       
  3931 ** The update hook implementation must not do anything that will modify
       
  3932 ** the database connection that invoked the update hook.  Any actions
       
  3933 ** to modify the database connection must be deferred until after the
       
  3934 ** completion of the [sqlite3_step()] call that triggered the update hook.
       
  3935 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  3936 ** database connections for the meaning of "modify" in this paragraph.
       
  3937 **
       
  3938 ** If another function was previously registered, its pArg value
       
  3939 ** is returned.  Otherwise NULL is returned.
       
  3940 **
       
  3941 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
       
  3942 ** interfaces.
       
  3943 **
       
  3944 ** Requirements:
       
  3945 ** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986]
       
  3946 */
       
  3947 SQLITE_API void *sqlite3_update_hook(
       
  3948   sqlite3*, 
       
  3949   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
       
  3950   void*
       
  3951 );
       
  3952 
       
  3953 /*
       
  3954 ** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900>
       
  3955 ** KEYWORDS: {shared cache}
       
  3956 **
       
  3957 ** This routine enables or disables the sharing of the database cache
       
  3958 ** and schema data structures between [database connection | connections]
       
  3959 ** to the same database. Sharing is enabled if the argument is true
       
  3960 ** and disabled if the argument is false.
       
  3961 **
       
  3962 ** Cache sharing is enabled and disabled for an entire process.
       
  3963 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
       
  3964 ** sharing was enabled or disabled for each thread separately.
       
  3965 **
       
  3966 ** The cache sharing mode set by this interface effects all subsequent
       
  3967 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
       
  3968 ** Existing database connections continue use the sharing mode
       
  3969 ** that was in effect at the time they were opened.
       
  3970 **
       
  3971 ** Virtual tables cannot be used with a shared cache.  When shared
       
  3972 ** cache is enabled, the [sqlite3_create_module()] API used to register
       
  3973 ** virtual tables will always return an error.
       
  3974 **
       
  3975 ** This routine returns [SQLITE_OK] if shared cache was enabled or disabled
       
  3976 ** successfully.  An [error code] is returned otherwise.
       
  3977 **
       
  3978 ** Shared cache is disabled by default. But this might change in
       
  3979 ** future releases of SQLite.  Applications that care about shared
       
  3980 ** cache setting should set it explicitly.
       
  3981 **
       
  3982 ** See Also:  [SQLite Shared-Cache Mode]
       
  3983 **
       
  3984 ** Requirements: [H10331] [H10336] [H10337] [H10339]
       
  3985 */
       
  3986 SQLITE_API int sqlite3_enable_shared_cache(int);
       
  3987 
       
  3988 /*
       
  3989 ** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220>
       
  3990 **
       
  3991 ** The sqlite3_release_memory() interface attempts to free N bytes
       
  3992 ** of heap memory by deallocating non-essential memory allocations
       
  3993 ** held by the database library. {END}  Memory used to cache database
       
  3994 ** pages to improve performance is an example of non-essential memory.
       
  3995 ** sqlite3_release_memory() returns the number of bytes actually freed,
       
  3996 ** which might be more or less than the amount requested.
       
  3997 **
       
  3998 ** Requirements: [H17341] [H17342]
       
  3999 */
       
  4000 SQLITE_API int sqlite3_release_memory(int);
       
  4001 
       
  4002 /*
       
  4003 ** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220>
       
  4004 **
       
  4005 ** The sqlite3_soft_heap_limit() interface places a "soft" limit
       
  4006 ** on the amount of heap memory that may be allocated by SQLite.
       
  4007 ** If an internal allocation is requested that would exceed the
       
  4008 ** soft heap limit, [sqlite3_release_memory()] is invoked one or
       
  4009 ** more times to free up some space before the allocation is performed.
       
  4010 **
       
  4011 ** The limit is called "soft", because if [sqlite3_release_memory()]
       
  4012 ** cannot free sufficient memory to prevent the limit from being exceeded,
       
  4013 ** the memory is allocated anyway and the current operation proceeds.
       
  4014 **
       
  4015 ** A negative or zero value for N means that there is no soft heap limit and
       
  4016 ** [sqlite3_release_memory()] will only be called when memory is exhausted.
       
  4017 ** The default value for the soft heap limit is zero.
       
  4018 **
       
  4019 ** SQLite makes a best effort to honor the soft heap limit.
       
  4020 ** But if the soft heap limit cannot be honored, execution will
       
  4021 ** continue without error or notification.  This is why the limit is
       
  4022 ** called a "soft" limit.  It is advisory only.
       
  4023 **
       
  4024 ** Prior to SQLite version 3.5.0, this routine only constrained the memory
       
  4025 ** allocated by a single thread - the same thread in which this routine
       
  4026 ** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
       
  4027 ** applied to all threads. The value specified for the soft heap limit
       
  4028 ** is an upper bound on the total memory allocation for all threads. In
       
  4029 ** version 3.5.0 there is no mechanism for limiting the heap usage for
       
  4030 ** individual threads.
       
  4031 **
       
  4032 ** Requirements:
       
  4033 ** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358]
       
  4034 */
       
  4035 SQLITE_API void sqlite3_soft_heap_limit(int);
       
  4036 
       
  4037 /*
       
  4038 ** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300>
       
  4039 **
       
  4040 ** This routine returns metadata about a specific column of a specific
       
  4041 ** database table accessible using the [database connection] handle
       
  4042 ** passed as the first function argument.
       
  4043 **
       
  4044 ** The column is identified by the second, third and fourth parameters to
       
  4045 ** this function. The second parameter is either the name of the database
       
  4046 ** (i.e. "main", "temp" or an attached database) containing the specified
       
  4047 ** table or NULL. If it is NULL, then all attached databases are searched
       
  4048 ** for the table using the same algorithm used by the database engine to
       
  4049 ** resolve unqualified table references.
       
  4050 **
       
  4051 ** The third and fourth parameters to this function are the table and column
       
  4052 ** name of the desired column, respectively. Neither of these parameters
       
  4053 ** may be NULL.
       
  4054 **
       
  4055 ** Metadata is returned by writing to the memory locations passed as the 5th
       
  4056 ** and subsequent parameters to this function. Any of these arguments may be
       
  4057 ** NULL, in which case the corresponding element of metadata is omitted.
       
  4058 **
       
  4059 ** <blockquote>
       
  4060 ** <table border="1">
       
  4061 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
       
  4062 **
       
  4063 ** <tr><td> 5th <td> const char* <td> Data type
       
  4064 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
       
  4065 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
       
  4066 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
       
  4067 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
       
  4068 ** </table>
       
  4069 ** </blockquote>
       
  4070 **
       
  4071 ** The memory pointed to by the character pointers returned for the
       
  4072 ** declaration type and collation sequence is valid only until the next
       
  4073 ** call to any SQLite API function.
       
  4074 **
       
  4075 ** If the specified table is actually a view, an [error code] is returned.
       
  4076 **
       
  4077 ** If the specified column is "rowid", "oid" or "_rowid_" and an
       
  4078 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
       
  4079 ** parameters are set for the explicitly declared column. If there is no
       
  4080 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
       
  4081 ** parameters are set as follows:
       
  4082 **
       
  4083 ** <pre>
       
  4084 **     data type: "INTEGER"
       
  4085 **     collation sequence: "BINARY"
       
  4086 **     not null: 0
       
  4087 **     primary key: 1
       
  4088 **     auto increment: 0
       
  4089 ** </pre>
       
  4090 **
       
  4091 ** This function may load one or more schemas from database files. If an
       
  4092 ** error occurs during this process, or if the requested table or column
       
  4093 ** cannot be found, an [error code] is returned and an error message left
       
  4094 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).
       
  4095 **
       
  4096 ** This API is only available if the library was compiled with the
       
  4097 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
       
  4098 */
       
  4099 SQLITE_API int sqlite3_table_column_metadata(
       
  4100   sqlite3 *db,                /* Connection handle */
       
  4101   const char *zDbName,        /* Database name or NULL */
       
  4102   const char *zTableName,     /* Table name */
       
  4103   const char *zColumnName,    /* Column name */
       
  4104   char const **pzDataType,    /* OUTPUT: Declared data type */
       
  4105   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
       
  4106   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
       
  4107   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
       
  4108   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
       
  4109 );
       
  4110 
       
  4111 /*
       
  4112 ** CAPI3REF: Load An Extension {H12600} <S20500>
       
  4113 **
       
  4114 ** This interface loads an SQLite extension library from the named file.
       
  4115 **
       
  4116 ** {H12601} The sqlite3_load_extension() interface attempts to load an
       
  4117 **          SQLite extension library contained in the file zFile.
       
  4118 **
       
  4119 ** {H12602} The entry point is zProc.
       
  4120 **
       
  4121 ** {H12603} zProc may be 0, in which case the name of the entry point
       
  4122 **          defaults to "sqlite3_extension_init".
       
  4123 **
       
  4124 ** {H12604} The sqlite3_load_extension() interface shall return
       
  4125 **          [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
       
  4126 **
       
  4127 ** {H12605} If an error occurs and pzErrMsg is not 0, then the
       
  4128 **          [sqlite3_load_extension()] interface shall attempt to
       
  4129 **          fill *pzErrMsg with error message text stored in memory
       
  4130 **          obtained from [sqlite3_malloc()]. {END}  The calling function
       
  4131 **          should free this memory by calling [sqlite3_free()].
       
  4132 **
       
  4133 ** {H12606} Extension loading must be enabled using
       
  4134 **          [sqlite3_enable_load_extension()] prior to calling this API,
       
  4135 **          otherwise an error will be returned.
       
  4136 */
       
  4137 SQLITE_API int sqlite3_load_extension(
       
  4138   sqlite3 *db,          /* Load the extension into this database connection */
       
  4139   const char *zFile,    /* Name of the shared library containing extension */
       
  4140   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
       
  4141   char **pzErrMsg       /* Put error message here if not 0 */
       
  4142 );
       
  4143 
       
  4144 /*
       
  4145 ** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500>
       
  4146 **
       
  4147 ** So as not to open security holes in older applications that are
       
  4148 ** unprepared to deal with extension loading, and as a means of disabling
       
  4149 ** extension loading while evaluating user-entered SQL, the following API
       
  4150 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
       
  4151 **
       
  4152 ** Extension loading is off by default. See ticket #1863.
       
  4153 **
       
  4154 ** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1
       
  4155 **          to turn extension loading on and call it with onoff==0 to turn
       
  4156 **          it back off again.
       
  4157 **
       
  4158 ** {H12622} Extension loading is off by default.
       
  4159 */
       
  4160 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
       
  4161 
       
  4162 /*
       
  4163 ** CAPI3REF: Automatically Load An Extensions {H12640} <S20500>
       
  4164 **
       
  4165 ** This API can be invoked at program startup in order to register
       
  4166 ** one or more statically linked extensions that will be available
       
  4167 ** to all new [database connections]. {END}
       
  4168 **
       
  4169 ** This routine stores a pointer to the extension in an array that is
       
  4170 ** obtained from [sqlite3_malloc()].  If you run a memory leak checker
       
  4171 ** on your program and it reports a leak because of this array, invoke
       
  4172 ** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory.
       
  4173 **
       
  4174 ** {H12641} This function registers an extension entry point that is
       
  4175 **          automatically invoked whenever a new [database connection]
       
  4176 **          is opened using [sqlite3_open()], [sqlite3_open16()],
       
  4177 **          or [sqlite3_open_v2()].
       
  4178 **
       
  4179 ** {H12642} Duplicate extensions are detected so calling this routine
       
  4180 **          multiple times with the same extension is harmless.
       
  4181 **
       
  4182 ** {H12643} This routine stores a pointer to the extension in an array
       
  4183 **          that is obtained from [sqlite3_malloc()].
       
  4184 **
       
  4185 ** {H12644} Automatic extensions apply across all threads.
       
  4186 */
       
  4187 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void));
       
  4188 
       
  4189 /*
       
  4190 ** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500>
       
  4191 **
       
  4192 ** This function disables all previously registered automatic
       
  4193 ** extensions. {END}  It undoes the effect of all prior
       
  4194 ** [sqlite3_auto_extension()] calls.
       
  4195 **
       
  4196 ** {H12661} This function disables all previously registered
       
  4197 **          automatic extensions.
       
  4198 **
       
  4199 ** {H12662} This function disables automatic extensions in all threads.
       
  4200 */
       
  4201 SQLITE_API void sqlite3_reset_auto_extension(void);
       
  4202 
       
  4203 /*
       
  4204 ****** EXPERIMENTAL - subject to change without notice **************
       
  4205 **
       
  4206 ** The interface to the virtual-table mechanism is currently considered
       
  4207 ** to be experimental.  The interface might change in incompatible ways.
       
  4208 ** If this is a problem for you, do not use the interface at this time.
       
  4209 **
       
  4210 ** When the virtual-table mechanism stabilizes, we will declare the
       
  4211 ** interface fixed, support it indefinitely, and remove this comment.
       
  4212 */
       
  4213 
       
  4214 /*
       
  4215 ** Structures used by the virtual table interface
       
  4216 */
       
  4217 typedef struct sqlite3_vtab sqlite3_vtab;
       
  4218 typedef struct sqlite3_index_info sqlite3_index_info;
       
  4219 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
       
  4220 typedef struct sqlite3_module sqlite3_module;
       
  4221 
       
  4222 /*
       
  4223 ** CAPI3REF: Virtual Table Object {H18000} <S20400>
       
  4224 ** KEYWORDS: sqlite3_module {virtual table module}
       
  4225 ** EXPERIMENTAL
       
  4226 **
       
  4227 ** This structure, sometimes called a a "virtual table module", 
       
  4228 ** defines the implementation of a [virtual tables].  
       
  4229 ** This structure consists mostly of methods for the module.
       
  4230 **
       
  4231 ** A virtual table module is created by filling in a persistent
       
  4232 ** instance of this structure and passing a pointer to that instance
       
  4233 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
       
  4234 ** The registration remains valid until it is replaced by a different
       
  4235 ** module or until the [database connection] closes.  The content
       
  4236 ** of this structure must not change while it is registered with
       
  4237 ** any database connection.
       
  4238 */
       
  4239 struct sqlite3_module {
       
  4240   int iVersion;
       
  4241   int (*xCreate)(sqlite3*, void *pAux,
       
  4242                int argc, const char *const*argv,
       
  4243                sqlite3_vtab **ppVTab, char**);
       
  4244   int (*xConnect)(sqlite3*, void *pAux,
       
  4245                int argc, const char *const*argv,
       
  4246                sqlite3_vtab **ppVTab, char**);
       
  4247   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
       
  4248   int (*xDisconnect)(sqlite3_vtab *pVTab);
       
  4249   int (*xDestroy)(sqlite3_vtab *pVTab);
       
  4250   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
       
  4251   int (*xClose)(sqlite3_vtab_cursor*);
       
  4252   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
       
  4253                 int argc, sqlite3_value **argv);
       
  4254   int (*xNext)(sqlite3_vtab_cursor*);
       
  4255   int (*xEof)(sqlite3_vtab_cursor*);
       
  4256   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
       
  4257   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
       
  4258   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
       
  4259   int (*xBegin)(sqlite3_vtab *pVTab);
       
  4260   int (*xSync)(sqlite3_vtab *pVTab);
       
  4261   int (*xCommit)(sqlite3_vtab *pVTab);
       
  4262   int (*xRollback)(sqlite3_vtab *pVTab);
       
  4263   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
       
  4264                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
       
  4265                        void **ppArg);
       
  4266   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
       
  4267 };
       
  4268 
       
  4269 /*
       
  4270 ** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400>
       
  4271 ** KEYWORDS: sqlite3_index_info
       
  4272 ** EXPERIMENTAL
       
  4273 **
       
  4274 ** The sqlite3_index_info structure and its substructures is used to
       
  4275 ** pass information into and receive the reply from the [xBestIndex]
       
  4276 ** method of a [virtual table module].  The fields under **Inputs** are the
       
  4277 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
       
  4278 ** results into the **Outputs** fields.
       
  4279 **
       
  4280 ** The aConstraint[] array records WHERE clause constraints of the form:
       
  4281 **
       
  4282 ** <pre>column OP expr</pre>
       
  4283 **
       
  4284 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.  The particular operator is
       
  4285 ** stored in aConstraint[].op.  The index of the column is stored in
       
  4286 ** aConstraint[].iColumn.  aConstraint[].usable is TRUE if the
       
  4287 ** expr on the right-hand side can be evaluated (and thus the constraint
       
  4288 ** is usable) and false if it cannot.
       
  4289 **
       
  4290 ** The optimizer automatically inverts terms of the form "expr OP column"
       
  4291 ** and makes other simplifications to the WHERE clause in an attempt to
       
  4292 ** get as many WHERE clause terms into the form shown above as possible.
       
  4293 ** The aConstraint[] array only reports WHERE clause terms in the correct
       
  4294 ** form that refer to the particular virtual table being queried.
       
  4295 **
       
  4296 ** Information about the ORDER BY clause is stored in aOrderBy[].
       
  4297 ** Each term of aOrderBy records a column of the ORDER BY clause.
       
  4298 **
       
  4299 ** The [xBestIndex] method must fill aConstraintUsage[] with information
       
  4300 ** about what parameters to pass to xFilter.  If argvIndex>0 then
       
  4301 ** the right-hand side of the corresponding aConstraint[] is evaluated
       
  4302 ** and becomes the argvIndex-th entry in argv.  If aConstraintUsage[].omit
       
  4303 ** is true, then the constraint is assumed to be fully handled by the
       
  4304 ** virtual table and is not checked again by SQLite.
       
  4305 **
       
  4306 ** The idxNum and idxPtr values are recorded and passed into the
       
  4307 ** [xFilter] method.
       
  4308 ** [sqlite3_free()] is used to free idxPtr if and only iff
       
  4309 ** needToFreeIdxPtr is true.
       
  4310 **
       
  4311 ** The orderByConsumed means that output from [xFilter]/[xNext] will occur in
       
  4312 ** the correct order to satisfy the ORDER BY clause so that no separate
       
  4313 ** sorting step is required.
       
  4314 **
       
  4315 ** The estimatedCost value is an estimate of the cost of doing the
       
  4316 ** particular lookup.  A full scan of a table with N entries should have
       
  4317 ** a cost of N.  A binary search of a table of N entries should have a
       
  4318 ** cost of approximately log(N).
       
  4319 */
       
  4320 struct sqlite3_index_info {
       
  4321   /* Inputs */
       
  4322   int nConstraint;           /* Number of entries in aConstraint */
       
  4323   struct sqlite3_index_constraint {
       
  4324      int iColumn;              /* Column on left-hand side of constraint */
       
  4325      unsigned char op;         /* Constraint operator */
       
  4326      unsigned char usable;     /* True if this constraint is usable */
       
  4327      int iTermOffset;          /* Used internally - xBestIndex should ignore */
       
  4328   } *aConstraint;            /* Table of WHERE clause constraints */
       
  4329   int nOrderBy;              /* Number of terms in the ORDER BY clause */
       
  4330   struct sqlite3_index_orderby {
       
  4331      int iColumn;              /* Column number */
       
  4332      unsigned char desc;       /* True for DESC.  False for ASC. */
       
  4333   } *aOrderBy;               /* The ORDER BY clause */
       
  4334   /* Outputs */
       
  4335   struct sqlite3_index_constraint_usage {
       
  4336     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
       
  4337     unsigned char omit;      /* Do not code a test for this constraint */
       
  4338   } *aConstraintUsage;
       
  4339   int idxNum;                /* Number used to identify the index */
       
  4340   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
       
  4341   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
       
  4342   int orderByConsumed;       /* True if output is already ordered */
       
  4343   double estimatedCost;      /* Estimated cost of using this index */
       
  4344 };
       
  4345 #define SQLITE_INDEX_CONSTRAINT_EQ    2
       
  4346 #define SQLITE_INDEX_CONSTRAINT_GT    4
       
  4347 #define SQLITE_INDEX_CONSTRAINT_LE    8
       
  4348 #define SQLITE_INDEX_CONSTRAINT_LT    16
       
  4349 #define SQLITE_INDEX_CONSTRAINT_GE    32
       
  4350 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
       
  4351 
       
  4352 /*
       
  4353 ** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400>
       
  4354 ** EXPERIMENTAL
       
  4355 **
       
  4356 ** This routine is used to register a new [virtual table module] name.
       
  4357 ** Module names must be registered before
       
  4358 ** creating a new [virtual table] using the module, or before using a
       
  4359 ** preexisting [virtual table] for the module.
       
  4360 **
       
  4361 ** The module name is registered on the [database connection] specified
       
  4362 ** by the first parameter.  The name of the module is given by the 
       
  4363 ** second parameter.  The third parameter is a pointer to
       
  4364 ** the implementation of the [virtual table module].   The fourth
       
  4365 ** parameter is an arbitrary client data pointer that is passed through
       
  4366 ** into the [xCreate] and [xConnect] methods of the virtual table module
       
  4367 ** when a new virtual table is be being created or reinitialized.
       
  4368 **
       
  4369 ** This interface has exactly the same effect as calling
       
  4370 ** [sqlite3_create_module_v2()] with a NULL client data destructor.
       
  4371 */
       
  4372 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module(
       
  4373   sqlite3 *db,               /* SQLite connection to register module with */
       
  4374   const char *zName,         /* Name of the module */
       
  4375   const sqlite3_module *p,   /* Methods for the module */
       
  4376   void *pClientData          /* Client data for xCreate/xConnect */
       
  4377 );
       
  4378 
       
  4379 /*
       
  4380 ** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400>
       
  4381 ** EXPERIMENTAL
       
  4382 **
       
  4383 ** This routine is identical to the [sqlite3_create_module()] method,
       
  4384 ** except that it has an extra parameter to specify 
       
  4385 ** a destructor function for the client data pointer.  SQLite will
       
  4386 ** invoke the destructor function (if it is not NULL) when SQLite
       
  4387 ** no longer needs the pClientData pointer.  
       
  4388 */
       
  4389 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module_v2(
       
  4390   sqlite3 *db,               /* SQLite connection to register module with */
       
  4391   const char *zName,         /* Name of the module */
       
  4392   const sqlite3_module *p,   /* Methods for the module */
       
  4393   void *pClientData,         /* Client data for xCreate/xConnect */
       
  4394   void(*xDestroy)(void*)     /* Module destructor function */
       
  4395 );
       
  4396 
       
  4397 /*
       
  4398 ** CAPI3REF: Virtual Table Instance Object {H18010} <S20400>
       
  4399 ** KEYWORDS: sqlite3_vtab
       
  4400 ** EXPERIMENTAL
       
  4401 **
       
  4402 ** Every [virtual table module] implementation uses a subclass
       
  4403 ** of the following structure to describe a particular instance
       
  4404 ** of the [virtual table].  Each subclass will
       
  4405 ** be tailored to the specific needs of the module implementation.
       
  4406 ** The purpose of this superclass is to define certain fields that are
       
  4407 ** common to all module implementations.
       
  4408 **
       
  4409 ** Virtual tables methods can set an error message by assigning a
       
  4410 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
       
  4411 ** take care that any prior string is freed by a call to [sqlite3_free()]
       
  4412 ** prior to assigning a new string to zErrMsg.  After the error message
       
  4413 ** is delivered up to the client application, the string will be automatically
       
  4414 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
       
  4415 */
       
  4416 struct sqlite3_vtab {
       
  4417   const sqlite3_module *pModule;  /* The module for this virtual table */
       
  4418   int nRef;                       /* NO LONGER USED */
       
  4419   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
       
  4420   /* Virtual table implementations will typically add additional fields */
       
  4421 };
       
  4422 
       
  4423 /*
       
  4424 ** CAPI3REF: Virtual Table Cursor Object  {H18020} <S20400>
       
  4425 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
       
  4426 ** EXPERIMENTAL
       
  4427 **
       
  4428 ** Every [virtual table module] implementation uses a subclass of the
       
  4429 ** following structure to describe cursors that point into the
       
  4430 ** [virtual table] and are used
       
  4431 ** to loop through the virtual table.  Cursors are created using the
       
  4432 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
       
  4433 ** by the [sqlite3_module.xClose | xClose] method.  Cussors are used
       
  4434 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
       
  4435 ** of the module.  Each module implementation will define
       
  4436 ** the content of a cursor structure to suit its own needs.
       
  4437 **
       
  4438 ** This superclass exists in order to define fields of the cursor that
       
  4439 ** are common to all implementations.
       
  4440 */
       
  4441 struct sqlite3_vtab_cursor {
       
  4442   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
       
  4443   /* Virtual table implementations will typically add additional fields */
       
  4444 };
       
  4445 
       
  4446 /*
       
  4447 ** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400>
       
  4448 ** EXPERIMENTAL
       
  4449 **
       
  4450 ** The [xCreate] and [xConnect] methods of a
       
  4451 ** [virtual table module] call this interface
       
  4452 ** to declare the format (the names and datatypes of the columns) of
       
  4453 ** the virtual tables they implement.
       
  4454 */
       
  4455 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
       
  4456 
       
  4457 /*
       
  4458 ** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400>
       
  4459 ** EXPERIMENTAL
       
  4460 **
       
  4461 ** Virtual tables can provide alternative implementations of functions
       
  4462 ** using the [xFindFunction] method of the [virtual table module].  
       
  4463 ** But global versions of those functions
       
  4464 ** must exist in order to be overloaded.
       
  4465 **
       
  4466 ** This API makes sure a global version of a function with a particular
       
  4467 ** name and number of parameters exists.  If no such function exists
       
  4468 ** before this API is called, a new function is created.  The implementation
       
  4469 ** of the new function always causes an exception to be thrown.  So
       
  4470 ** the new function is not good for anything by itself.  Its only
       
  4471 ** purpose is to be a placeholder function that can be overloaded
       
  4472 ** by a [virtual table].
       
  4473 */
       
  4474 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
       
  4475 
       
  4476 /*
       
  4477 ** The interface to the virtual-table mechanism defined above (back up
       
  4478 ** to a comment remarkably similar to this one) is currently considered
       
  4479 ** to be experimental.  The interface might change in incompatible ways.
       
  4480 ** If this is a problem for you, do not use the interface at this time.
       
  4481 **
       
  4482 ** When the virtual-table mechanism stabilizes, we will declare the
       
  4483 ** interface fixed, support it indefinitely, and remove this comment.
       
  4484 **
       
  4485 ****** EXPERIMENTAL - subject to change without notice **************
       
  4486 */
       
  4487 
       
  4488 /*
       
  4489 ** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230>
       
  4490 ** KEYWORDS: {BLOB handle} {BLOB handles}
       
  4491 **
       
  4492 ** An instance of this object represents an open BLOB on which
       
  4493 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
       
  4494 ** Objects of this type are created by [sqlite3_blob_open()]
       
  4495 ** and destroyed by [sqlite3_blob_close()].
       
  4496 ** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
       
  4497 ** can be used to read or write small subsections of the BLOB.
       
  4498 ** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
       
  4499 */
       
  4500 typedef struct sqlite3_blob sqlite3_blob;
       
  4501 
       
  4502 /*
       
  4503 ** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230>
       
  4504 **
       
  4505 ** This interfaces opens a [BLOB handle | handle] to the BLOB located
       
  4506 ** in row iRow, column zColumn, table zTable in database zDb;
       
  4507 ** in other words, the same BLOB that would be selected by:
       
  4508 **
       
  4509 ** <pre>
       
  4510 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
       
  4511 ** </pre> {END}
       
  4512 **
       
  4513 ** If the flags parameter is non-zero, then the BLOB is opened for read
       
  4514 ** and write access. If it is zero, the BLOB is opened for read access.
       
  4515 ** It is not possible to open a column that is part of an index or primary 
       
  4516 ** key for writing. ^If [foreign key constraints] are enabled, it is 
       
  4517 ** not possible to open a column that is part of a [child key] for writing.
       
  4518 **
       
  4519 ** Note that the database name is not the filename that contains
       
  4520 ** the database but rather the symbolic name of the database that
       
  4521 ** is assigned when the database is connected using [ATTACH].
       
  4522 ** For the main database file, the database name is "main".
       
  4523 ** For TEMP tables, the database name is "temp".
       
  4524 **
       
  4525 ** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
       
  4526 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set
       
  4527 ** to be a null pointer.
       
  4528 ** This function sets the [database connection] error code and message
       
  4529 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related
       
  4530 ** functions.  Note that the *ppBlob variable is always initialized in a
       
  4531 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob
       
  4532 ** regardless of the success or failure of this routine.
       
  4533 **
       
  4534 ** If the row that a BLOB handle points to is modified by an
       
  4535 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
       
  4536 ** then the BLOB handle is marked as "expired".
       
  4537 ** This is true if any column of the row is changed, even a column
       
  4538 ** other than the one the BLOB handle is open on.
       
  4539 ** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
       
  4540 ** a expired BLOB handle fail with an return code of [SQLITE_ABORT].
       
  4541 ** Changes written into a BLOB prior to the BLOB expiring are not
       
  4542 ** rollback by the expiration of the BLOB.  Such changes will eventually
       
  4543 ** commit if the transaction continues to completion.
       
  4544 **
       
  4545 ** Use the [sqlite3_blob_bytes()] interface to determine the size of
       
  4546 ** the opened blob.  The size of a blob may not be changed by this
       
  4547 ** interface.  Use the [UPDATE] SQL command to change the size of a
       
  4548 ** blob.
       
  4549 **
       
  4550 ** The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
       
  4551 ** and the built-in [zeroblob] SQL function can be used, if desired,
       
  4552 ** to create an empty, zero-filled blob in which to read or write using
       
  4553 ** this interface.
       
  4554 **
       
  4555 ** To avoid a resource leak, every open [BLOB handle] should eventually
       
  4556 ** be released by a call to [sqlite3_blob_close()].
       
  4557 **
       
  4558 ** Requirements:
       
  4559 ** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824]
       
  4560 */
       
  4561 SQLITE_API int sqlite3_blob_open(
       
  4562   sqlite3*,
       
  4563   const char *zDb,
       
  4564   const char *zTable,
       
  4565   const char *zColumn,
       
  4566   sqlite3_int64 iRow,
       
  4567   int flags,
       
  4568   sqlite3_blob **ppBlob
       
  4569 );
       
  4570 
       
  4571 /*
       
  4572 ** CAPI3REF: Close A BLOB Handle {H17830} <S30230>
       
  4573 **
       
  4574 ** Closes an open [BLOB handle].
       
  4575 **
       
  4576 ** Closing a BLOB shall cause the current transaction to commit
       
  4577 ** if there are no other BLOBs, no pending prepared statements, and the
       
  4578 ** database connection is in [autocommit mode].
       
  4579 ** If any writes were made to the BLOB, they might be held in cache
       
  4580 ** until the close operation if they will fit.
       
  4581 **
       
  4582 ** Closing the BLOB often forces the changes
       
  4583 ** out to disk and so if any I/O errors occur, they will likely occur
       
  4584 ** at the time when the BLOB is closed.  Any errors that occur during
       
  4585 ** closing are reported as a non-zero return value.
       
  4586 **
       
  4587 ** The BLOB is closed unconditionally.  Even if this routine returns
       
  4588 ** an error code, the BLOB is still closed.
       
  4589 **
       
  4590 ** Calling this routine with a null pointer (which as would be returned
       
  4591 ** by failed call to [sqlite3_blob_open()]) is a harmless no-op.
       
  4592 **
       
  4593 ** Requirements:
       
  4594 ** [H17833] [H17836] [H17839]
       
  4595 */
       
  4596 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
       
  4597 
       
  4598 /*
       
  4599 ** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230>
       
  4600 **
       
  4601 ** Returns the size in bytes of the BLOB accessible via the 
       
  4602 ** successfully opened [BLOB handle] in its only argument.  The
       
  4603 ** incremental blob I/O routines can only read or overwriting existing
       
  4604 ** blob content; they cannot change the size of a blob.
       
  4605 **
       
  4606 ** This routine only works on a [BLOB handle] which has been created
       
  4607 ** by a prior successful call to [sqlite3_blob_open()] and which has not
       
  4608 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
       
  4609 ** to this routine results in undefined and probably undesirable behavior.
       
  4610 **
       
  4611 ** Requirements:
       
  4612 ** [H17843]
       
  4613 */
       
  4614 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
       
  4615 
       
  4616 /*
       
  4617 ** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230>
       
  4618 **
       
  4619 ** This function is used to read data from an open [BLOB handle] into a
       
  4620 ** caller-supplied buffer. N bytes of data are copied into buffer Z
       
  4621 ** from the open BLOB, starting at offset iOffset.
       
  4622 **
       
  4623 ** If offset iOffset is less than N bytes from the end of the BLOB,
       
  4624 ** [SQLITE_ERROR] is returned and no data is read.  If N or iOffset is
       
  4625 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
       
  4626 ** The size of the blob (and hence the maximum value of N+iOffset)
       
  4627 ** can be determined using the [sqlite3_blob_bytes()] interface.
       
  4628 **
       
  4629 ** An attempt to read from an expired [BLOB handle] fails with an
       
  4630 ** error code of [SQLITE_ABORT].
       
  4631 **
       
  4632 ** On success, SQLITE_OK is returned.
       
  4633 ** Otherwise, an [error code] or an [extended error code] is returned.
       
  4634 **
       
  4635 ** This routine only works on a [BLOB handle] which has been created
       
  4636 ** by a prior successful call to [sqlite3_blob_open()] and which has not
       
  4637 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
       
  4638 ** to this routine results in undefined and probably undesirable behavior.
       
  4639 **
       
  4640 ** See also: [sqlite3_blob_write()].
       
  4641 **
       
  4642 ** Requirements:
       
  4643 ** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868]
       
  4644 */
       
  4645 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
       
  4646 
       
  4647 /*
       
  4648 ** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230>
       
  4649 **
       
  4650 ** This function is used to write data into an open [BLOB handle] from a
       
  4651 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
       
  4652 ** into the open BLOB, starting at offset iOffset.
       
  4653 **
       
  4654 ** If the [BLOB handle] passed as the first argument was not opened for
       
  4655 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
       
  4656 ** this function returns [SQLITE_READONLY].
       
  4657 **
       
  4658 ** This function may only modify the contents of the BLOB; it is
       
  4659 ** not possible to increase the size of a BLOB using this API.
       
  4660 ** If offset iOffset is less than N bytes from the end of the BLOB,
       
  4661 ** [SQLITE_ERROR] is returned and no data is written.  If N is
       
  4662 ** less than zero [SQLITE_ERROR] is returned and no data is written.
       
  4663 ** The size of the BLOB (and hence the maximum value of N+iOffset)
       
  4664 ** can be determined using the [sqlite3_blob_bytes()] interface.
       
  4665 **
       
  4666 ** An attempt to write to an expired [BLOB handle] fails with an
       
  4667 ** error code of [SQLITE_ABORT].  Writes to the BLOB that occurred
       
  4668 ** before the [BLOB handle] expired are not rolled back by the
       
  4669 ** expiration of the handle, though of course those changes might
       
  4670 ** have been overwritten by the statement that expired the BLOB handle
       
  4671 ** or by other independent statements.
       
  4672 **
       
  4673 ** On success, SQLITE_OK is returned.
       
  4674 ** Otherwise, an  [error code] or an [extended error code] is returned.
       
  4675 **
       
  4676 ** This routine only works on a [BLOB handle] which has been created
       
  4677 ** by a prior successful call to [sqlite3_blob_open()] and which has not
       
  4678 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
       
  4679 ** to this routine results in undefined and probably undesirable behavior.
       
  4680 **
       
  4681 ** See also: [sqlite3_blob_read()].
       
  4682 **
       
  4683 ** Requirements:
       
  4684 ** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885]
       
  4685 ** [H17888]
       
  4686 */
       
  4687 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
       
  4688 
       
  4689 /*
       
  4690 ** CAPI3REF: Virtual File System Objects {H11200} <S20100>
       
  4691 **
       
  4692 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
       
  4693 ** that SQLite uses to interact
       
  4694 ** with the underlying operating system.  Most SQLite builds come with a
       
  4695 ** single default VFS that is appropriate for the host computer.
       
  4696 ** New VFSes can be registered and existing VFSes can be unregistered.
       
  4697 ** The following interfaces are provided.
       
  4698 **
       
  4699 ** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
       
  4700 ** Names are case sensitive.
       
  4701 ** Names are zero-terminated UTF-8 strings.
       
  4702 ** If there is no match, a NULL pointer is returned.
       
  4703 ** If zVfsName is NULL then the default VFS is returned.
       
  4704 **
       
  4705 ** New VFSes are registered with sqlite3_vfs_register().
       
  4706 ** Each new VFS becomes the default VFS if the makeDflt flag is set.
       
  4707 ** The same VFS can be registered multiple times without injury.
       
  4708 ** To make an existing VFS into the default VFS, register it again
       
  4709 ** with the makeDflt flag set.  If two different VFSes with the
       
  4710 ** same name are registered, the behavior is undefined.  If a
       
  4711 ** VFS is registered with a name that is NULL or an empty string,
       
  4712 ** then the behavior is undefined.
       
  4713 **
       
  4714 ** Unregister a VFS with the sqlite3_vfs_unregister() interface.
       
  4715 ** If the default VFS is unregistered, another VFS is chosen as
       
  4716 ** the default.  The choice for the new VFS is arbitrary.
       
  4717 **
       
  4718 ** Requirements:
       
  4719 ** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218]
       
  4720 */
       
  4721 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
       
  4722 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
       
  4723 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
       
  4724 
       
  4725 /*
       
  4726 ** CAPI3REF: Mutexes {H17000} <S20000>
       
  4727 **
       
  4728 ** The SQLite core uses these routines for thread
       
  4729 ** synchronization. Though they are intended for internal
       
  4730 ** use by SQLite, code that links against SQLite is
       
  4731 ** permitted to use any of these routines.
       
  4732 **
       
  4733 ** The SQLite source code contains multiple implementations
       
  4734 ** of these mutex routines.  An appropriate implementation
       
  4735 ** is selected automatically at compile-time.  The following
       
  4736 ** implementations are available in the SQLite core:
       
  4737 **
       
  4738 ** <ul>
       
  4739 ** <li>   SQLITE_MUTEX_OS2
       
  4740 ** <li>   SQLITE_MUTEX_PTHREAD
       
  4741 ** <li>   SQLITE_MUTEX_W32
       
  4742 ** <li>   SQLITE_MUTEX_NOOP
       
  4743 ** </ul>
       
  4744 **
       
  4745 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
       
  4746 ** that does no real locking and is appropriate for use in
       
  4747 ** a single-threaded application.  The SQLITE_MUTEX_OS2,
       
  4748 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
       
  4749 ** are appropriate for use on OS/2, Unix, and Windows.
       
  4750 **
       
  4751 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
       
  4752 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
       
  4753 ** implementation is included with the library. In this case the
       
  4754 ** application must supply a custom mutex implementation using the
       
  4755 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
       
  4756 ** before calling sqlite3_initialize() or any other public sqlite3_
       
  4757 ** function that calls sqlite3_initialize().
       
  4758 **
       
  4759 ** {H17011} The sqlite3_mutex_alloc() routine allocates a new
       
  4760 ** mutex and returns a pointer to it. {H17012} If it returns NULL
       
  4761 ** that means that a mutex could not be allocated. {H17013} SQLite
       
  4762 ** will unwind its stack and return an error. {H17014} The argument
       
  4763 ** to sqlite3_mutex_alloc() is one of these integer constants:
       
  4764 **
       
  4765 ** <ul>
       
  4766 ** <li>  SQLITE_MUTEX_FAST
       
  4767 ** <li>  SQLITE_MUTEX_RECURSIVE
       
  4768 ** <li>  SQLITE_MUTEX_STATIC_MASTER
       
  4769 ** <li>  SQLITE_MUTEX_STATIC_MEM
       
  4770 ** <li>  SQLITE_MUTEX_STATIC_MEM2
       
  4771 ** <li>  SQLITE_MUTEX_STATIC_PRNG
       
  4772 ** <li>  SQLITE_MUTEX_STATIC_LRU
       
  4773 ** <li>  SQLITE_MUTEX_STATIC_LRU2
       
  4774 ** </ul>
       
  4775 **
       
  4776 ** {H17015} The first two constants cause sqlite3_mutex_alloc() to create
       
  4777 ** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
       
  4778 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
       
  4779 ** The mutex implementation does not need to make a distinction
       
  4780 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
       
  4781 ** not want to.  {H17016} But SQLite will only request a recursive mutex in
       
  4782 ** cases where it really needs one.  {END} If a faster non-recursive mutex
       
  4783 ** implementation is available on the host platform, the mutex subsystem
       
  4784 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
       
  4785 **
       
  4786 ** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return
       
  4787 ** a pointer to a static preexisting mutex. {END}  Six static mutexes are
       
  4788 ** used by the current version of SQLite.  Future versions of SQLite
       
  4789 ** may add additional static mutexes.  Static mutexes are for internal
       
  4790 ** use by SQLite only.  Applications that use SQLite mutexes should
       
  4791 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
       
  4792 ** SQLITE_MUTEX_RECURSIVE.
       
  4793 **
       
  4794 ** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
       
  4795 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
       
  4796 ** returns a different mutex on every call.  {H17034} But for the static
       
  4797 ** mutex types, the same mutex is returned on every call that has
       
  4798 ** the same type number.
       
  4799 **
       
  4800 ** {H17019} The sqlite3_mutex_free() routine deallocates a previously
       
  4801 ** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every
       
  4802 ** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in
       
  4803 ** use when they are deallocated. {A17022} Attempting to deallocate a static
       
  4804 ** mutex results in undefined behavior. {H17023} SQLite never deallocates
       
  4805 ** a static mutex. {END}
       
  4806 **
       
  4807 ** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
       
  4808 ** to enter a mutex. {H17024} If another thread is already within the mutex,
       
  4809 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
       
  4810 ** SQLITE_BUSY. {H17025}  The sqlite3_mutex_try() interface returns [SQLITE_OK]
       
  4811 ** upon successful entry.  {H17026} Mutexes created using
       
  4812 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
       
  4813 ** {H17027} In such cases the,
       
  4814 ** mutex must be exited an equal number of times before another thread
       
  4815 ** can enter.  {A17028} If the same thread tries to enter any other
       
  4816 ** kind of mutex more than once, the behavior is undefined.
       
  4817 ** {H17029} SQLite will never exhibit
       
  4818 ** such behavior in its own use of mutexes.
       
  4819 **
       
  4820 ** Some systems (for example, Windows 95) do not support the operation
       
  4821 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
       
  4822 ** will always return SQLITE_BUSY.  {H17030} The SQLite core only ever uses
       
  4823 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
       
  4824 **
       
  4825 ** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was
       
  4826 ** previously entered by the same thread.  {A17032} The behavior
       
  4827 ** is undefined if the mutex is not currently entered by the
       
  4828 ** calling thread or is not currently allocated.  {H17033} SQLite will
       
  4829 ** never do either. {END}
       
  4830 **
       
  4831 ** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
       
  4832 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
       
  4833 ** behave as no-ops.
       
  4834 **
       
  4835 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
       
  4836 */
       
  4837 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
       
  4838 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
       
  4839 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
       
  4840 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
       
  4841 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
       
  4842 
       
  4843 /*
       
  4844 ** CAPI3REF: Mutex Methods Object {H17120} <S20130>
       
  4845 ** EXPERIMENTAL
       
  4846 **
       
  4847 ** An instance of this structure defines the low-level routines
       
  4848 ** used to allocate and use mutexes.
       
  4849 **
       
  4850 ** Usually, the default mutex implementations provided by SQLite are
       
  4851 ** sufficient, however the user has the option of substituting a custom
       
  4852 ** implementation for specialized deployments or systems for which SQLite
       
  4853 ** does not provide a suitable implementation. In this case, the user
       
  4854 ** creates and populates an instance of this structure to pass
       
  4855 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
       
  4856 ** Additionally, an instance of this structure can be used as an
       
  4857 ** output variable when querying the system for the current mutex
       
  4858 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
       
  4859 **
       
  4860 ** The xMutexInit method defined by this structure is invoked as
       
  4861 ** part of system initialization by the sqlite3_initialize() function.
       
  4862 ** {H17001} The xMutexInit routine shall be called by SQLite once for each
       
  4863 ** effective call to [sqlite3_initialize()].
       
  4864 **
       
  4865 ** The xMutexEnd method defined by this structure is invoked as
       
  4866 ** part of system shutdown by the sqlite3_shutdown() function. The
       
  4867 ** implementation of this method is expected to release all outstanding
       
  4868 ** resources obtained by the mutex methods implementation, especially
       
  4869 ** those obtained by the xMutexInit method. {H17003} The xMutexEnd()
       
  4870 ** interface shall be invoked once for each call to [sqlite3_shutdown()].
       
  4871 **
       
  4872 ** The remaining seven methods defined by this structure (xMutexAlloc,
       
  4873 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
       
  4874 ** xMutexNotheld) implement the following interfaces (respectively):
       
  4875 **
       
  4876 ** <ul>
       
  4877 **   <li>  [sqlite3_mutex_alloc()] </li>
       
  4878 **   <li>  [sqlite3_mutex_free()] </li>
       
  4879 **   <li>  [sqlite3_mutex_enter()] </li>
       
  4880 **   <li>  [sqlite3_mutex_try()] </li>
       
  4881 **   <li>  [sqlite3_mutex_leave()] </li>
       
  4882 **   <li>  [sqlite3_mutex_held()] </li>
       
  4883 **   <li>  [sqlite3_mutex_notheld()] </li>
       
  4884 ** </ul>
       
  4885 **
       
  4886 ** The only difference is that the public sqlite3_XXX functions enumerated
       
  4887 ** above silently ignore any invocations that pass a NULL pointer instead
       
  4888 ** of a valid mutex handle. The implementations of the methods defined
       
  4889 ** by this structure are not required to handle this case, the results
       
  4890 ** of passing a NULL pointer instead of a valid mutex handle are undefined
       
  4891 ** (i.e. it is acceptable to provide an implementation that segfaults if
       
  4892 ** it is passed a NULL pointer).
       
  4893 **
       
  4894 ** The xMutexInit() method must be threadsafe.  It must be harmless to
       
  4895 ** invoke xMutexInit() mutiple times within the same process and without
       
  4896 ** intervening calls to xMutexEnd().  Second and subsequent calls to
       
  4897 ** xMutexInit() must be no-ops.
       
  4898 **
       
  4899 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
       
  4900 ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
       
  4901 ** allocation for a static mutex.  However xMutexAlloc() may use SQLite
       
  4902 ** memory allocation for a fast or recursive mutex.
       
  4903 **
       
  4904 ** SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
       
  4905 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
       
  4906 ** If xMutexInit fails in any way, it is expected to clean up after itself
       
  4907 ** prior to returning.
       
  4908 */
       
  4909 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
       
  4910 struct sqlite3_mutex_methods {
       
  4911   int (*xMutexInit)(void);
       
  4912   int (*xMutexEnd)(void);
       
  4913   sqlite3_mutex *(*xMutexAlloc)(int);
       
  4914   void (*xMutexFree)(sqlite3_mutex *);
       
  4915   void (*xMutexEnter)(sqlite3_mutex *);
       
  4916   int (*xMutexTry)(sqlite3_mutex *);
       
  4917   void (*xMutexLeave)(sqlite3_mutex *);
       
  4918   int (*xMutexHeld)(sqlite3_mutex *);
       
  4919   int (*xMutexNotheld)(sqlite3_mutex *);
       
  4920 };
       
  4921 
       
  4922 /*
       
  4923 ** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800>
       
  4924 **
       
  4925 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
       
  4926 ** are intended for use inside assert() statements. {H17081} The SQLite core
       
  4927 ** never uses these routines except inside an assert() and applications
       
  4928 ** are advised to follow the lead of the core.  {H17082} The core only
       
  4929 ** provides implementations for these routines when it is compiled
       
  4930 ** with the SQLITE_DEBUG flag.  {A17087} External mutex implementations
       
  4931 ** are only required to provide these routines if SQLITE_DEBUG is
       
  4932 ** defined and if NDEBUG is not defined.
       
  4933 **
       
  4934 ** {H17083} These routines should return true if the mutex in their argument
       
  4935 ** is held or not held, respectively, by the calling thread.
       
  4936 **
       
  4937 ** {X17084} The implementation is not required to provided versions of these
       
  4938 ** routines that actually work. If the implementation does not provide working
       
  4939 ** versions of these routines, it should at least provide stubs that always
       
  4940 ** return true so that one does not get spurious assertion failures.
       
  4941 **
       
  4942 ** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
       
  4943 ** the routine should return 1.  {END} This seems counter-intuitive since
       
  4944 ** clearly the mutex cannot be held if it does not exist.  But the
       
  4945 ** the reason the mutex does not exist is because the build is not
       
  4946 ** using mutexes.  And we do not want the assert() containing the
       
  4947 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
       
  4948 ** the appropriate thing to do.  {H17086} The sqlite3_mutex_notheld()
       
  4949 ** interface should also return 1 when given a NULL pointer.
       
  4950 */
       
  4951 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
       
  4952 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
       
  4953 
       
  4954 /*
       
  4955 ** CAPI3REF: Mutex Types {H17001} <H17000>
       
  4956 **
       
  4957 ** The [sqlite3_mutex_alloc()] interface takes a single argument
       
  4958 ** which is one of these integer constants.
       
  4959 **
       
  4960 ** The set of static mutexes may change from one SQLite release to the
       
  4961 ** next.  Applications that override the built-in mutex logic must be
       
  4962 ** prepared to accommodate additional static mutexes.
       
  4963 */
       
  4964 #define SQLITE_MUTEX_FAST             0
       
  4965 #define SQLITE_MUTEX_RECURSIVE        1
       
  4966 #define SQLITE_MUTEX_STATIC_MASTER    2
       
  4967 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
       
  4968 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
       
  4969 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
       
  4970 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
       
  4971 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
       
  4972 #define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */
       
  4973 
       
  4974 /*
       
  4975 ** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000>
       
  4976 **
       
  4977 ** This interface returns a pointer the [sqlite3_mutex] object that 
       
  4978 ** serializes access to the [database connection] given in the argument
       
  4979 ** when the [threading mode] is Serialized.
       
  4980 ** If the [threading mode] is Single-thread or Multi-thread then this
       
  4981 ** routine returns a NULL pointer.
       
  4982 */
       
  4983 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
       
  4984 
       
  4985 /*
       
  4986 ** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800>
       
  4987 **
       
  4988 ** {H11301} The [sqlite3_file_control()] interface makes a direct call to the
       
  4989 ** xFileControl method for the [sqlite3_io_methods] object associated
       
  4990 ** with a particular database identified by the second argument. {H11302} The
       
  4991 ** name of the database is the name assigned to the database by the
       
  4992 ** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
       
  4993 ** database. {H11303} To control the main database file, use the name "main"
       
  4994 ** or a NULL pointer. {H11304} The third and fourth parameters to this routine
       
  4995 ** are passed directly through to the second and third parameters of
       
  4996 ** the xFileControl method.  {H11305} The return value of the xFileControl
       
  4997 ** method becomes the return value of this routine.
       
  4998 **
       
  4999 ** {H11306} If the second parameter (zDbName) does not match the name of any
       
  5000 ** open database file, then SQLITE_ERROR is returned. {H11307} This error
       
  5001 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
       
  5002 ** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might
       
  5003 ** also return SQLITE_ERROR.  {A11309} There is no way to distinguish between
       
  5004 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
       
  5005 ** xFileControl method. {END}
       
  5006 **
       
  5007 ** See also: [SQLITE_FCNTL_LOCKSTATE]
       
  5008 */
       
  5009 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
       
  5010 
       
  5011 /*
       
  5012 ** CAPI3REF: Testing Interface {H11400} <S30800>
       
  5013 **
       
  5014 ** The sqlite3_test_control() interface is used to read out internal
       
  5015 ** state of SQLite and to inject faults into SQLite for testing
       
  5016 ** purposes.  The first parameter is an operation code that determines
       
  5017 ** the number, meaning, and operation of all subsequent parameters.
       
  5018 **
       
  5019 ** This interface is not for use by applications.  It exists solely
       
  5020 ** for verifying the correct operation of the SQLite library.  Depending
       
  5021 ** on how the SQLite library is compiled, this interface might not exist.
       
  5022 **
       
  5023 ** The details of the operation codes, their meanings, the parameters
       
  5024 ** they take, and what they do are all subject to change without notice.
       
  5025 ** Unlike most of the SQLite API, this function is not guaranteed to
       
  5026 ** operate consistently from one release to the next.
       
  5027 */
       
  5028 SQLITE_API int sqlite3_test_control(int op, ...);
       
  5029 
       
  5030 /*
       
  5031 ** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400>
       
  5032 **
       
  5033 ** These constants are the valid operation code parameters used
       
  5034 ** as the first argument to [sqlite3_test_control()].
       
  5035 **
       
  5036 ** These parameters and their meanings are subject to change
       
  5037 ** without notice.  These values are for testing purposes only.
       
  5038 ** Applications should not use any of these parameters or the
       
  5039 ** [sqlite3_test_control()] interface.
       
  5040 */
       
  5041 #define SQLITE_TESTCTRL_PRNG_SAVE                5
       
  5042 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
       
  5043 #define SQLITE_TESTCTRL_PRNG_RESET               7
       
  5044 #define SQLITE_TESTCTRL_BITVEC_TEST              8
       
  5045 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
       
  5046 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
       
  5047 #define SQLITE_TESTCTRL_PENDING_BYTE            11
       
  5048 #define SQLITE_TESTCTRL_ASSERT                  12
       
  5049 #define SQLITE_TESTCTRL_ALWAYS                  13
       
  5050 #define SQLITE_TESTCTRL_RESERVE                 14
       
  5051 
       
  5052 /*
       
  5053 ** CAPI3REF: SQLite Runtime Status {H17200} <S60200>
       
  5054 ** EXPERIMENTAL
       
  5055 **
       
  5056 ** This interface is used to retrieve runtime status information
       
  5057 ** about the preformance of SQLite, and optionally to reset various
       
  5058 ** highwater marks.  The first argument is an integer code for
       
  5059 ** the specific parameter to measure.  Recognized integer codes
       
  5060 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].
       
  5061 ** The current value of the parameter is returned into *pCurrent.
       
  5062 ** The highest recorded value is returned in *pHighwater.  If the
       
  5063 ** resetFlag is true, then the highest record value is reset after
       
  5064 ** *pHighwater is written. Some parameters do not record the highest
       
  5065 ** value.  For those parameters
       
  5066 ** nothing is written into *pHighwater and the resetFlag is ignored.
       
  5067 ** Other parameters record only the highwater mark and not the current
       
  5068 ** value.  For these latter parameters nothing is written into *pCurrent.
       
  5069 **
       
  5070 ** This routine returns SQLITE_OK on success and a non-zero
       
  5071 ** [error code] on failure.
       
  5072 **
       
  5073 ** This routine is threadsafe but is not atomic.  This routine can be
       
  5074 ** called while other threads are running the same or different SQLite
       
  5075 ** interfaces.  However the values returned in *pCurrent and
       
  5076 ** *pHighwater reflect the status of SQLite at different points in time
       
  5077 ** and it is possible that another thread might change the parameter
       
  5078 ** in between the times when *pCurrent and *pHighwater are written.
       
  5079 **
       
  5080 ** See also: [sqlite3_db_status()]
       
  5081 */
       
  5082 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
       
  5083 
       
  5084 
       
  5085 /*
       
  5086 ** CAPI3REF: Status Parameters {H17250} <H17200>
       
  5087 ** EXPERIMENTAL
       
  5088 **
       
  5089 ** These integer constants designate various run-time status parameters
       
  5090 ** that can be returned by [sqlite3_status()].
       
  5091 **
       
  5092 ** <dl>
       
  5093 ** <dt>SQLITE_STATUS_MEMORY_USED</dt>
       
  5094 ** <dd>This parameter is the current amount of memory checked out
       
  5095 ** using [sqlite3_malloc()], either directly or indirectly.  The
       
  5096 ** figure includes calls made to [sqlite3_malloc()] by the application
       
  5097 ** and internal memory usage by the SQLite library.  Scratch memory
       
  5098 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
       
  5099 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
       
  5100 ** this parameter.  The amount returned is the sum of the allocation
       
  5101 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>
       
  5102 **
       
  5103 ** <dt>SQLITE_STATUS_MALLOC_SIZE</dt>
       
  5104 ** <dd>This parameter records the largest memory allocation request
       
  5105 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
       
  5106 ** internal equivalents).  Only the value returned in the
       
  5107 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  5108 ** The value written into the *pCurrent parameter is undefined.</dd>
       
  5109 **
       
  5110 ** <dt>SQLITE_STATUS_PAGECACHE_USED</dt>
       
  5111 ** <dd>This parameter returns the number of pages used out of the
       
  5112 ** [pagecache memory allocator] that was configured using 
       
  5113 ** [SQLITE_CONFIG_PAGECACHE].  The
       
  5114 ** value returned is in pages, not in bytes.</dd>
       
  5115 **
       
  5116 ** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
       
  5117 ** <dd>This parameter returns the number of bytes of page cache
       
  5118 ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE]
       
  5119 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
       
  5120 ** returned value includes allocations that overflowed because they
       
  5121 ** where too large (they were larger than the "sz" parameter to
       
  5122 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
       
  5123 ** no space was left in the page cache.</dd>
       
  5124 **
       
  5125 ** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
       
  5126 ** <dd>This parameter records the largest memory allocation request
       
  5127 ** handed to [pagecache memory allocator].  Only the value returned in the
       
  5128 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  5129 ** The value written into the *pCurrent parameter is undefined.</dd>
       
  5130 **
       
  5131 ** <dt>SQLITE_STATUS_SCRATCH_USED</dt>
       
  5132 ** <dd>This parameter returns the number of allocations used out of the
       
  5133 ** [scratch memory allocator] configured using
       
  5134 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
       
  5135 ** in bytes.  Since a single thread may only have one scratch allocation
       
  5136 ** outstanding at time, this parameter also reports the number of threads
       
  5137 ** using scratch memory at the same time.</dd>
       
  5138 **
       
  5139 ** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
       
  5140 ** <dd>This parameter returns the number of bytes of scratch memory
       
  5141 ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH]
       
  5142 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
       
  5143 ** returned include overflows because the requested allocation was too
       
  5144 ** larger (that is, because the requested allocation was larger than the
       
  5145 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
       
  5146 ** slots were available.
       
  5147 ** </dd>
       
  5148 **
       
  5149 ** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
       
  5150 ** <dd>This parameter records the largest memory allocation request
       
  5151 ** handed to [scratch memory allocator].  Only the value returned in the
       
  5152 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  5153 ** The value written into the *pCurrent parameter is undefined.</dd>
       
  5154 **
       
  5155 ** <dt>SQLITE_STATUS_PARSER_STACK</dt>
       
  5156 ** <dd>This parameter records the deepest parser stack.  It is only
       
  5157 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>
       
  5158 ** </dl>
       
  5159 **
       
  5160 ** New status parameters may be added from time to time.
       
  5161 */
       
  5162 #define SQLITE_STATUS_MEMORY_USED          0
       
  5163 #define SQLITE_STATUS_PAGECACHE_USED       1
       
  5164 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
       
  5165 #define SQLITE_STATUS_SCRATCH_USED         3
       
  5166 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4
       
  5167 #define SQLITE_STATUS_MALLOC_SIZE          5
       
  5168 #define SQLITE_STATUS_PARSER_STACK         6
       
  5169 #define SQLITE_STATUS_PAGECACHE_SIZE       7
       
  5170 #define SQLITE_STATUS_SCRATCH_SIZE         8
       
  5171 
       
  5172 /*
       
  5173 ** CAPI3REF: Database Connection Status {H17500} <S60200>
       
  5174 ** EXPERIMENTAL
       
  5175 **
       
  5176 ** This interface is used to retrieve runtime status information 
       
  5177 ** about a single [database connection].  The first argument is the
       
  5178 ** database connection object to be interrogated.  The second argument
       
  5179 ** is the parameter to interrogate.  Currently, the only allowed value
       
  5180 ** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
       
  5181 ** Additional options will likely appear in future releases of SQLite.
       
  5182 **
       
  5183 ** The current value of the requested parameter is written into *pCur
       
  5184 ** and the highest instantaneous value is written into *pHiwtr.  If
       
  5185 ** the resetFlg is true, then the highest instantaneous value is
       
  5186 ** reset back down to the current value.
       
  5187 **
       
  5188 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
       
  5189 */
       
  5190 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
       
  5191 
       
  5192 /*
       
  5193 ** CAPI3REF: Status Parameters for database connections {H17520} <H17500>
       
  5194 ** EXPERIMENTAL
       
  5195 **
       
  5196 ** These constants are the available integer "verbs" that can be passed as
       
  5197 ** the second argument to the [sqlite3_db_status()] interface.
       
  5198 **
       
  5199 ** New verbs may be added in future releases of SQLite. Existing verbs
       
  5200 ** might be discontinued. Applications should check the return code from
       
  5201 ** [sqlite3_db_status()] to make sure that the call worked.
       
  5202 ** The [sqlite3_db_status()] interface will return a non-zero error code
       
  5203 ** if a discontinued or unsupported verb is invoked.
       
  5204 **
       
  5205 ** <dl>
       
  5206 ** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
       
  5207 ** <dd>This parameter returns the number of lookaside memory slots currently
       
  5208 ** checked out.</dd>
       
  5209 ** </dl>
       
  5210 */
       
  5211 #define SQLITE_DBSTATUS_LOOKASIDE_USED     0
       
  5212 
       
  5213 
       
  5214 /*
       
  5215 ** CAPI3REF: Prepared Statement Status {H17550} <S60200>
       
  5216 ** EXPERIMENTAL
       
  5217 **
       
  5218 ** Each prepared statement maintains various
       
  5219 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
       
  5220 ** of times it has performed specific operations.  These counters can
       
  5221 ** be used to monitor the performance characteristics of the prepared
       
  5222 ** statements.  For example, if the number of table steps greatly exceeds
       
  5223 ** the number of table searches or result rows, that would tend to indicate
       
  5224 ** that the prepared statement is using a full table scan rather than
       
  5225 ** an index.  
       
  5226 **
       
  5227 ** This interface is used to retrieve and reset counter values from
       
  5228 ** a [prepared statement].  The first argument is the prepared statement
       
  5229 ** object to be interrogated.  The second argument
       
  5230 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
       
  5231 ** to be interrogated. 
       
  5232 ** The current value of the requested counter is returned.
       
  5233 ** If the resetFlg is true, then the counter is reset to zero after this
       
  5234 ** interface call returns.
       
  5235 **
       
  5236 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
       
  5237 */
       
  5238 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
       
  5239 
       
  5240 /*
       
  5241 ** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550>
       
  5242 ** EXPERIMENTAL
       
  5243 **
       
  5244 ** These preprocessor macros define integer codes that name counter
       
  5245 ** values associated with the [sqlite3_stmt_status()] interface.
       
  5246 ** The meanings of the various counters are as follows:
       
  5247 **
       
  5248 ** <dl>
       
  5249 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
       
  5250 ** <dd>This is the number of times that SQLite has stepped forward in
       
  5251 ** a table as part of a full table scan.  Large numbers for this counter
       
  5252 ** may indicate opportunities for performance improvement through 
       
  5253 ** careful use of indices.</dd>
       
  5254 **
       
  5255 ** <dt>SQLITE_STMTSTATUS_SORT</dt>
       
  5256 ** <dd>This is the number of sort operations that have occurred.
       
  5257 ** A non-zero value in this counter may indicate an opportunity to
       
  5258 ** improvement performance through careful use of indices.</dd>
       
  5259 **
       
  5260 ** </dl>
       
  5261 */
       
  5262 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
       
  5263 #define SQLITE_STMTSTATUS_SORT              2
       
  5264 
       
  5265 /*
       
  5266 ** CAPI3REF: Custom Page Cache Object
       
  5267 ** EXPERIMENTAL
       
  5268 **
       
  5269 ** The sqlite3_pcache type is opaque.  It is implemented by
       
  5270 ** the pluggable module.  The SQLite core has no knowledge of
       
  5271 ** its size or internal structure and never deals with the
       
  5272 ** sqlite3_pcache object except by holding and passing pointers
       
  5273 ** to the object.
       
  5274 **
       
  5275 ** See [sqlite3_pcache_methods] for additional information.
       
  5276 */
       
  5277 typedef struct sqlite3_pcache sqlite3_pcache;
       
  5278 
       
  5279 /*
       
  5280 ** CAPI3REF: Application Defined Page Cache.
       
  5281 ** KEYWORDS: {page cache}
       
  5282 ** EXPERIMENTAL
       
  5283 **
       
  5284 ** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
       
  5285 ** register an alternative page cache implementation by passing in an 
       
  5286 ** instance of the sqlite3_pcache_methods structure. The majority of the 
       
  5287 ** heap memory used by SQLite is used by the page cache to cache data read 
       
  5288 ** from, or ready to be written to, the database file. By implementing a 
       
  5289 ** custom page cache using this API, an application can control more 
       
  5290 ** precisely the amount of memory consumed by SQLite, the way in which 
       
  5291 ** that memory is allocated and released, and the policies used to 
       
  5292 ** determine exactly which parts of a database file are cached and for 
       
  5293 ** how long.
       
  5294 **
       
  5295 ** The contents of the sqlite3_pcache_methods structure are copied to an
       
  5296 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
       
  5297 ** the application may discard the parameter after the call to
       
  5298 ** [sqlite3_config()] returns.
       
  5299 **
       
  5300 ** The xInit() method is called once for each call to [sqlite3_initialize()]
       
  5301 ** (usually only once during the lifetime of the process). It is passed
       
  5302 ** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set
       
  5303 ** up global structures and mutexes required by the custom page cache 
       
  5304 ** implementation. 
       
  5305 **
       
  5306 ** The xShutdown() method is called from within [sqlite3_shutdown()], 
       
  5307 ** if the application invokes this API. It can be used to clean up 
       
  5308 ** any outstanding resources before process shutdown, if required.
       
  5309 **
       
  5310 ** SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes
       
  5311 ** the xInit method, so the xInit method need not be threadsafe.  The
       
  5312 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
       
  5313 ** not need to be threadsafe either.  All other methods must be threadsafe
       
  5314 ** in multithreaded applications.
       
  5315 **
       
  5316 ** SQLite will never invoke xInit() more than once without an intervening
       
  5317 ** call to xShutdown().
       
  5318 **
       
  5319 ** The xCreate() method is used to construct a new cache instance.  SQLite
       
  5320 ** will typically create one cache instance for each open database file,
       
  5321 ** though this is not guaranteed. The
       
  5322 ** first parameter, szPage, is the size in bytes of the pages that must
       
  5323 ** be allocated by the cache.  szPage will not be a power of two.  szPage
       
  5324 ** will the page size of the database file that is to be cached plus an
       
  5325 ** increment (here called "R") of about 100 or 200.  SQLite will use the
       
  5326 ** extra R bytes on each page to store metadata about the underlying
       
  5327 ** database page on disk.  The value of R depends
       
  5328 ** on the SQLite version, the target platform, and how SQLite was compiled.
       
  5329 ** R is constant for a particular build of SQLite.  The second argument to
       
  5330 ** xCreate(), bPurgeable, is true if the cache being created will
       
  5331 ** be used to cache database pages of a file stored on disk, or
       
  5332 ** false if it is used for an in-memory database. The cache implementation
       
  5333 ** does not have to do anything special based with the value of bPurgeable;
       
  5334 ** it is purely advisory.  On a cache where bPurgeable is false, SQLite will
       
  5335 ** never invoke xUnpin() except to deliberately delete a page.
       
  5336 ** In other words, a cache created with bPurgeable set to false will
       
  5337 ** never contain any unpinned pages.
       
  5338 **
       
  5339 ** The xCachesize() method may be called at any time by SQLite to set the
       
  5340 ** suggested maximum cache-size (number of pages stored by) the cache
       
  5341 ** instance passed as the first argument. This is the value configured using
       
  5342 ** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter,
       
  5343 ** the implementation is not required to do anything with this
       
  5344 ** value; it is advisory only.
       
  5345 **
       
  5346 ** The xPagecount() method should return the number of pages currently
       
  5347 ** stored in the cache.
       
  5348 ** 
       
  5349 ** The xFetch() method is used to fetch a page and return a pointer to it. 
       
  5350 ** A 'page', in this context, is a buffer of szPage bytes aligned at an
       
  5351 ** 8-byte boundary. The page to be fetched is determined by the key. The
       
  5352 ** mimimum key value is 1. After it has been retrieved using xFetch, the page 
       
  5353 ** is considered to be "pinned".
       
  5354 **
       
  5355 ** If the requested page is already in the page cache, then the page cache
       
  5356 ** implementation must return a pointer to the page buffer with its content
       
  5357 ** intact.  If the requested page is not already in the cache, then the
       
  5358 ** behavior of the cache implementation is determined by the value of the
       
  5359 ** createFlag parameter passed to xFetch, according to the following table:
       
  5360 **
       
  5361 ** <table border=1 width=85% align=center>
       
  5362 ** <tr><th> createFlag <th> Behaviour when page is not already in cache
       
  5363 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
       
  5364 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
       
  5365 **                 Otherwise return NULL.
       
  5366 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
       
  5367 **                 NULL if allocating a new page is effectively impossible.
       
  5368 ** </table>
       
  5369 **
       
  5370 ** SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  If
       
  5371 ** a call to xFetch() with createFlag==1 returns NULL, then SQLite will
       
  5372 ** attempt to unpin one or more cache pages by spilling the content of
       
  5373 ** pinned pages to disk and synching the operating system disk cache. After
       
  5374 ** attempting to unpin pages, the xFetch() method will be invoked again with
       
  5375 ** a createFlag of 2.
       
  5376 **
       
  5377 ** xUnpin() is called by SQLite with a pointer to a currently pinned page
       
  5378 ** as its second argument. If the third parameter, discard, is non-zero,
       
  5379 ** then the page should be evicted from the cache. In this case SQLite 
       
  5380 ** assumes that the next time the page is retrieved from the cache using
       
  5381 ** the xFetch() method, it will be zeroed. If the discard parameter is
       
  5382 ** zero, then the page is considered to be unpinned. The cache implementation
       
  5383 ** may choose to evict unpinned pages at any time.
       
  5384 **
       
  5385 ** The cache is not required to perform any reference counting. A single 
       
  5386 ** call to xUnpin() unpins the page regardless of the number of prior calls 
       
  5387 ** to xFetch().
       
  5388 **
       
  5389 ** The xRekey() method is used to change the key value associated with the
       
  5390 ** page passed as the second argument from oldKey to newKey. If the cache
       
  5391 ** previously contains an entry associated with newKey, it should be
       
  5392 ** discarded. Any prior cache entry associated with newKey is guaranteed not
       
  5393 ** to be pinned.
       
  5394 **
       
  5395 ** When SQLite calls the xTruncate() method, the cache must discard all
       
  5396 ** existing cache entries with page numbers (keys) greater than or equal
       
  5397 ** to the value of the iLimit parameter passed to xTruncate(). If any
       
  5398 ** of these pages are pinned, they are implicitly unpinned, meaning that
       
  5399 ** they can be safely discarded.
       
  5400 **
       
  5401 ** The xDestroy() method is used to delete a cache allocated by xCreate().
       
  5402 ** All resources associated with the specified cache should be freed. After
       
  5403 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
       
  5404 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
       
  5405 ** functions.
       
  5406 */
       
  5407 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
       
  5408 struct sqlite3_pcache_methods {
       
  5409   void *pArg;
       
  5410   int (*xInit)(void*);
       
  5411   void (*xShutdown)(void*);
       
  5412   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
       
  5413   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
       
  5414   int (*xPagecount)(sqlite3_pcache*);
       
  5415   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
       
  5416   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
       
  5417   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
       
  5418   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
       
  5419   void (*xDestroy)(sqlite3_pcache*);
       
  5420 };
       
  5421 
       
  5422 /*
       
  5423 ** CAPI3REF: Online Backup Object
       
  5424 ** EXPERIMENTAL
       
  5425 **
       
  5426 ** The sqlite3_backup object records state information about an ongoing
       
  5427 ** online backup operation.  The sqlite3_backup object is created by
       
  5428 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
       
  5429 ** [sqlite3_backup_finish()].
       
  5430 **
       
  5431 ** See Also: [Using the SQLite Online Backup API]
       
  5432 */
       
  5433 typedef struct sqlite3_backup sqlite3_backup;
       
  5434 
       
  5435 /*
       
  5436 ** CAPI3REF: Online Backup API.
       
  5437 ** EXPERIMENTAL
       
  5438 **
       
  5439 ** This API is used to overwrite the contents of one database with that
       
  5440 ** of another. It is useful either for creating backups of databases or
       
  5441 ** for copying in-memory databases to or from persistent files. 
       
  5442 **
       
  5443 ** See Also: [Using the SQLite Online Backup API]
       
  5444 **
       
  5445 ** Exclusive access is required to the destination database for the 
       
  5446 ** duration of the operation. However the source database is only
       
  5447 ** read-locked while it is actually being read, it is not locked
       
  5448 ** continuously for the entire operation. Thus, the backup may be
       
  5449 ** performed on a live database without preventing other users from
       
  5450 ** writing to the database for an extended period of time.
       
  5451 ** 
       
  5452 ** To perform a backup operation: 
       
  5453 **   <ol>
       
  5454 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
       
  5455 **         backup, 
       
  5456 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
       
  5457 **         the data between the two databases, and finally
       
  5458 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
       
  5459 **         associated with the backup operation. 
       
  5460 **   </ol>
       
  5461 ** There should be exactly one call to sqlite3_backup_finish() for each
       
  5462 ** successful call to sqlite3_backup_init().
       
  5463 **
       
  5464 ** <b>sqlite3_backup_init()</b>
       
  5465 **
       
  5466 ** The first two arguments passed to [sqlite3_backup_init()] are the database
       
  5467 ** handle associated with the destination database and the database name 
       
  5468 ** used to attach the destination database to the handle. The database name
       
  5469 ** is "main" for the main database, "temp" for the temporary database, or
       
  5470 ** the name specified as part of the [ATTACH] statement if the destination is
       
  5471 ** an attached database. The third and fourth arguments passed to 
       
  5472 ** sqlite3_backup_init() identify the [database connection]
       
  5473 ** and database name used
       
  5474 ** to access the source database. The values passed for the source and 
       
  5475 ** destination [database connection] parameters must not be the same.
       
  5476 **
       
  5477 ** If an error occurs within sqlite3_backup_init(), then NULL is returned
       
  5478 ** and an error code and error message written into the [database connection] 
       
  5479 ** passed as the first argument. They may be retrieved using the
       
  5480 ** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions.
       
  5481 ** Otherwise, if successful, a pointer to an [sqlite3_backup] object is
       
  5482 ** returned. This pointer may be used with the sqlite3_backup_step() and
       
  5483 ** sqlite3_backup_finish() functions to perform the specified backup 
       
  5484 ** operation.
       
  5485 **
       
  5486 ** <b>sqlite3_backup_step()</b>
       
  5487 **
       
  5488 ** Function [sqlite3_backup_step()] is used to copy up to nPage pages between 
       
  5489 ** the source and destination databases, where nPage is the value of the 
       
  5490 ** second parameter passed to sqlite3_backup_step(). If nPage is a negative
       
  5491 ** value, all remaining source pages are copied. If the required pages are 
       
  5492 ** succesfully copied, but there are still more pages to copy before the 
       
  5493 ** backup is complete, it returns [SQLITE_OK]. If no error occured and there 
       
  5494 ** are no more pages to copy, then [SQLITE_DONE] is returned. If an error 
       
  5495 ** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and
       
  5496 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
       
  5497 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
       
  5498 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
       
  5499 **
       
  5500 ** As well as the case where the destination database file was opened for
       
  5501 ** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if
       
  5502 ** the destination is an in-memory database with a different page size
       
  5503 ** from the source database.
       
  5504 **
       
  5505 ** If sqlite3_backup_step() cannot obtain a required file-system lock, then
       
  5506 ** the [sqlite3_busy_handler | busy-handler function]
       
  5507 ** is invoked (if one is specified). If the 
       
  5508 ** busy-handler returns non-zero before the lock is available, then 
       
  5509 ** [SQLITE_BUSY] is returned to the caller. In this case the call to
       
  5510 ** sqlite3_backup_step() can be retried later. If the source
       
  5511 ** [database connection]
       
  5512 ** is being used to write to the source database when sqlite3_backup_step()
       
  5513 ** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this
       
  5514 ** case the call to sqlite3_backup_step() can be retried later on. If
       
  5515 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
       
  5516 ** [SQLITE_READONLY] is returned, then 
       
  5517 ** there is no point in retrying the call to sqlite3_backup_step(). These 
       
  5518 ** errors are considered fatal. At this point the application must accept 
       
  5519 ** that the backup operation has failed and pass the backup operation handle 
       
  5520 ** to the sqlite3_backup_finish() to release associated resources.
       
  5521 **
       
  5522 ** Following the first call to sqlite3_backup_step(), an exclusive lock is
       
  5523 ** obtained on the destination file. It is not released until either 
       
  5524 ** sqlite3_backup_finish() is called or the backup operation is complete 
       
  5525 ** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time 
       
  5526 ** a call to sqlite3_backup_step() is made a [shared lock] is obtained on
       
  5527 ** the source database file. This lock is released before the
       
  5528 ** sqlite3_backup_step() call returns. Because the source database is not
       
  5529 ** locked between calls to sqlite3_backup_step(), it may be modified mid-way
       
  5530 ** through the backup procedure. If the source database is modified by an
       
  5531 ** external process or via a database connection other than the one being
       
  5532 ** used by the backup operation, then the backup will be transparently
       
  5533 ** restarted by the next call to sqlite3_backup_step(). If the source 
       
  5534 ** database is modified by the using the same database connection as is used
       
  5535 ** by the backup operation, then the backup database is transparently 
       
  5536 ** updated at the same time.
       
  5537 **
       
  5538 ** <b>sqlite3_backup_finish()</b>
       
  5539 **
       
  5540 ** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
       
  5541 ** application wishes to abandon the backup operation, the [sqlite3_backup]
       
  5542 ** object should be passed to sqlite3_backup_finish(). This releases all
       
  5543 ** resources associated with the backup operation. If sqlite3_backup_step()
       
  5544 ** has not yet returned [SQLITE_DONE], then any active write-transaction on the
       
  5545 ** destination database is rolled back. The [sqlite3_backup] object is invalid
       
  5546 ** and may not be used following a call to sqlite3_backup_finish().
       
  5547 **
       
  5548 ** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error
       
  5549 ** occurred, regardless or whether or not sqlite3_backup_step() was called
       
  5550 ** a sufficient number of times to complete the backup operation. Or, if
       
  5551 ** an out-of-memory condition or IO error occured during a call to
       
  5552 ** sqlite3_backup_step() then [SQLITE_NOMEM] or an
       
  5553 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code
       
  5554 ** is returned. In this case the error code and an error message are
       
  5555 ** written to the destination [database connection].
       
  5556 **
       
  5557 ** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is
       
  5558 ** not a permanent error and does not affect the return value of
       
  5559 ** sqlite3_backup_finish().
       
  5560 **
       
  5561 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
       
  5562 **
       
  5563 ** Each call to sqlite3_backup_step() sets two values stored internally
       
  5564 ** by an [sqlite3_backup] object. The number of pages still to be backed
       
  5565 ** up, which may be queried by sqlite3_backup_remaining(), and the total
       
  5566 ** number of pages in the source database file, which may be queried by
       
  5567 ** sqlite3_backup_pagecount().
       
  5568 **
       
  5569 ** The values returned by these functions are only updated by
       
  5570 ** sqlite3_backup_step(). If the source database is modified during a backup
       
  5571 ** operation, then the values are not updated to account for any extra
       
  5572 ** pages that need to be updated or the size of the source database file
       
  5573 ** changing.
       
  5574 **
       
  5575 ** <b>Concurrent Usage of Database Handles</b>
       
  5576 **
       
  5577 ** The source [database connection] may be used by the application for other
       
  5578 ** purposes while a backup operation is underway or being initialized.
       
  5579 ** If SQLite is compiled and configured to support threadsafe database
       
  5580 ** connections, then the source database connection may be used concurrently
       
  5581 ** from within other threads.
       
  5582 **
       
  5583 ** However, the application must guarantee that the destination database
       
  5584 ** connection handle is not passed to any other API (by any thread) after 
       
  5585 ** sqlite3_backup_init() is called and before the corresponding call to
       
  5586 ** sqlite3_backup_finish(). Unfortunately SQLite does not currently check
       
  5587 ** for this, if the application does use the destination [database connection]
       
  5588 ** for some other purpose during a backup operation, things may appear to
       
  5589 ** work correctly but in fact be subtly malfunctioning.  Use of the
       
  5590 ** destination database connection while a backup is in progress might
       
  5591 ** also cause a mutex deadlock.
       
  5592 **
       
  5593 ** Furthermore, if running in [shared cache mode], the application must
       
  5594 ** guarantee that the shared cache used by the destination database
       
  5595 ** is not accessed while the backup is running. In practice this means
       
  5596 ** that the application must guarantee that the file-system file being 
       
  5597 ** backed up to is not accessed by any connection within the process,
       
  5598 ** not just the specific connection that was passed to sqlite3_backup_init().
       
  5599 **
       
  5600 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
       
  5601 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
       
  5602 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
       
  5603 ** APIs are not strictly speaking threadsafe. If they are invoked at the
       
  5604 ** same time as another thread is invoking sqlite3_backup_step() it is
       
  5605 ** possible that they return invalid values.
       
  5606 */
       
  5607 SQLITE_API sqlite3_backup *sqlite3_backup_init(
       
  5608   sqlite3 *pDest,                        /* Destination database handle */
       
  5609   const char *zDestName,                 /* Destination database name */
       
  5610   sqlite3 *pSource,                      /* Source database handle */
       
  5611   const char *zSourceName                /* Source database name */
       
  5612 );
       
  5613 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
       
  5614 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
       
  5615 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
       
  5616 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
       
  5617 
       
  5618 /*
       
  5619 ** CAPI3REF: Unlock Notification
       
  5620 ** EXPERIMENTAL
       
  5621 **
       
  5622 ** When running in shared-cache mode, a database operation may fail with
       
  5623 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
       
  5624 ** individual tables within the shared-cache cannot be obtained. See
       
  5625 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
       
  5626 ** This API may be used to register a callback that SQLite will invoke 
       
  5627 ** when the connection currently holding the required lock relinquishes it.
       
  5628 ** This API is only available if the library was compiled with the
       
  5629 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
       
  5630 **
       
  5631 ** See Also: [Using the SQLite Unlock Notification Feature].
       
  5632 **
       
  5633 ** Shared-cache locks are released when a database connection concludes
       
  5634 ** its current transaction, either by committing it or rolling it back. 
       
  5635 **
       
  5636 ** When a connection (known as the blocked connection) fails to obtain a
       
  5637 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
       
  5638 ** identity of the database connection (the blocking connection) that
       
  5639 ** has locked the required resource is stored internally. After an 
       
  5640 ** application receives an SQLITE_LOCKED error, it may call the
       
  5641 ** sqlite3_unlock_notify() method with the blocked connection handle as 
       
  5642 ** the first argument to register for a callback that will be invoked
       
  5643 ** when the blocking connections current transaction is concluded. The
       
  5644 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
       
  5645 ** call that concludes the blocking connections transaction.
       
  5646 **
       
  5647 ** If sqlite3_unlock_notify() is called in a multi-threaded application,
       
  5648 ** there is a chance that the blocking connection will have already
       
  5649 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
       
  5650 ** If this happens, then the specified callback is invoked immediately,
       
  5651 ** from within the call to sqlite3_unlock_notify().
       
  5652 **
       
  5653 ** If the blocked connection is attempting to obtain a write-lock on a
       
  5654 ** shared-cache table, and more than one other connection currently holds
       
  5655 ** a read-lock on the same table, then SQLite arbitrarily selects one of 
       
  5656 ** the other connections to use as the blocking connection.
       
  5657 **
       
  5658 ** There may be at most one unlock-notify callback registered by a 
       
  5659 ** blocked connection. If sqlite3_unlock_notify() is called when the
       
  5660 ** blocked connection already has a registered unlock-notify callback,
       
  5661 ** then the new callback replaces the old. If sqlite3_unlock_notify() is
       
  5662 ** called with a NULL pointer as its second argument, then any existing
       
  5663 ** unlock-notify callback is cancelled. The blocked connections 
       
  5664 ** unlock-notify callback may also be canceled by closing the blocked
       
  5665 ** connection using [sqlite3_close()].
       
  5666 **
       
  5667 ** The unlock-notify callback is not reentrant. If an application invokes
       
  5668 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
       
  5669 ** crash or deadlock may be the result.
       
  5670 **
       
  5671 ** Unless deadlock is detected (see below), sqlite3_unlock_notify() always
       
  5672 ** returns SQLITE_OK.
       
  5673 **
       
  5674 ** <b>Callback Invocation Details</b>
       
  5675 **
       
  5676 ** When an unlock-notify callback is registered, the application provides a 
       
  5677 ** single void* pointer that is passed to the callback when it is invoked.
       
  5678 ** However, the signature of the callback function allows SQLite to pass
       
  5679 ** it an array of void* context pointers. The first argument passed to
       
  5680 ** an unlock-notify callback is a pointer to an array of void* pointers,
       
  5681 ** and the second is the number of entries in the array.
       
  5682 **
       
  5683 ** When a blocking connections transaction is concluded, there may be
       
  5684 ** more than one blocked connection that has registered for an unlock-notify
       
  5685 ** callback. If two or more such blocked connections have specified the
       
  5686 ** same callback function, then instead of invoking the callback function
       
  5687 ** multiple times, it is invoked once with the set of void* context pointers
       
  5688 ** specified by the blocked connections bundled together into an array.
       
  5689 ** This gives the application an opportunity to prioritize any actions 
       
  5690 ** related to the set of unblocked database connections.
       
  5691 **
       
  5692 ** <b>Deadlock Detection</b>
       
  5693 **
       
  5694 ** Assuming that after registering for an unlock-notify callback a 
       
  5695 ** database waits for the callback to be issued before taking any further
       
  5696 ** action (a reasonable assumption), then using this API may cause the
       
  5697 ** application to deadlock. For example, if connection X is waiting for
       
  5698 ** connection Y's transaction to be concluded, and similarly connection
       
  5699 ** Y is waiting on connection X's transaction, then neither connection
       
  5700 ** will proceed and the system may remain deadlocked indefinitely.
       
  5701 **
       
  5702 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
       
  5703 ** detection. If a given call to sqlite3_unlock_notify() would put the
       
  5704 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
       
  5705 ** unlock-notify callback is registered. The system is said to be in
       
  5706 ** a deadlocked state if connection A has registered for an unlock-notify
       
  5707 ** callback on the conclusion of connection B's transaction, and connection
       
  5708 ** B has itself registered for an unlock-notify callback when connection
       
  5709 ** A's transaction is concluded. Indirect deadlock is also detected, so
       
  5710 ** the system is also considered to be deadlocked if connection B has
       
  5711 ** registered for an unlock-notify callback on the conclusion of connection
       
  5712 ** C's transaction, where connection C is waiting on connection A. Any
       
  5713 ** number of levels of indirection are allowed.
       
  5714 **
       
  5715 ** <b>The "DROP TABLE" Exception</b>
       
  5716 **
       
  5717 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
       
  5718 ** always appropriate to call sqlite3_unlock_notify(). There is however,
       
  5719 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
       
  5720 ** SQLite checks if there are any currently executing SELECT statements
       
  5721 ** that belong to the same connection. If there are, SQLITE_LOCKED is
       
  5722 ** returned. In this case there is no "blocking connection", so invoking
       
  5723 ** sqlite3_unlock_notify() results in the unlock-notify callback being
       
  5724 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
       
  5725 ** or "DROP INDEX" query, an infinite loop might be the result.
       
  5726 **
       
  5727 ** One way around this problem is to check the extended error code returned
       
  5728 ** by an sqlite3_step() call. If there is a blocking connection, then the
       
  5729 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
       
  5730 ** the special "DROP TABLE/INDEX" case, the extended error code is just 
       
  5731 ** SQLITE_LOCKED.
       
  5732 */
       
  5733 SQLITE_API int sqlite3_unlock_notify(
       
  5734   sqlite3 *pBlocked,                          /* Waiting connection */
       
  5735   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
       
  5736   void *pNotifyArg                            /* Argument to pass to xNotify */
       
  5737 );
       
  5738 
       
  5739 
       
  5740 /*
       
  5741 ** CAPI3REF: String Comparison
       
  5742 ** EXPERIMENTAL
       
  5743 **
       
  5744 ** The [sqlite3_strnicmp()] API allows applications and extensions to
       
  5745 ** compare the contents of two buffers containing UTF-8 strings in a
       
  5746 ** case-indendent fashion, using the same definition of case independence 
       
  5747 ** that SQLite uses internally when comparing identifiers.
       
  5748 */
       
  5749 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
       
  5750 
       
  5751 /*
       
  5752 ** Undo the hack that converts floating point types to integer for
       
  5753 ** builds on processors without floating point support.
       
  5754 */
       
  5755 #ifdef SQLITE_OMIT_FLOATING_POINT
       
  5756 # undef double
       
  5757 #endif
       
  5758 
       
  5759 #ifdef __cplusplus
       
  5760 }  /* End of the 'extern "C"' block */
       
  5761 #endif
       
  5762 #endif
       
  5763