WebKitLibraries/WebCoreSQLite3/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 to make minor changes if
       
    22 ** 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 ** @(#) $Id: sqlite.h.in,v 1.436 2009/03/20 13:15:30 drh Exp $
       
    34 */
       
    35 #ifndef _SQLITE3_H_
       
    36 #define _SQLITE3_H_
       
    37 #include <stdarg.h>     /* Needed for the definition of va_list */
       
    38 
       
    39 /*
       
    40 ** Make sure we can call this stuff from C++.
       
    41 */
       
    42 #ifdef __cplusplus
       
    43 extern "C" {
       
    44 #endif
       
    45 
       
    46 
       
    47 /*
       
    48 ** Add the ability to override 'extern'
       
    49 */
       
    50 #ifndef SQLITE_EXTERN
       
    51 # define SQLITE_EXTERN extern
       
    52 #endif
       
    53 
       
    54 /*
       
    55 ** These no-op macros are used in front of interfaces to mark those
       
    56 ** interfaces as either deprecated or experimental.  New applications
       
    57 ** should not use deprecated intrfaces - they are support for backwards
       
    58 ** compatibility only.  Application writers should be aware that
       
    59 ** experimental interfaces are subject to change in point releases.
       
    60 **
       
    61 ** These macros used to resolve to various kinds of compiler magic that
       
    62 ** would generate warning messages when they were used.  But that
       
    63 ** compiler magic ended up generating such a flurry of bug reports
       
    64 ** that we have taken it all out and gone back to using simple
       
    65 ** noop macros.
       
    66 */
       
    67 #define SQLITE_DEPRECATED
       
    68 #define SQLITE_EXPERIMENTAL
       
    69 
       
    70 /*
       
    71 ** Ensure these symbols were not defined by some previous header file.
       
    72 */
       
    73 #ifdef SQLITE_VERSION
       
    74 # undef SQLITE_VERSION
       
    75 #endif
       
    76 #ifdef SQLITE_VERSION_NUMBER
       
    77 # undef SQLITE_VERSION_NUMBER
       
    78 #endif
       
    79 
       
    80 /*
       
    81 ** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100>
       
    82 **
       
    83 ** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in
       
    84 ** the sqlite3.h file specify the version of SQLite with which
       
    85 ** that header file is associated.
       
    86 **
       
    87 ** The "version" of SQLite is a string of the form "X.Y.Z".
       
    88 ** The phrase "alpha" or "beta" might be appended after the Z.
       
    89 ** The X value is major version number always 3 in SQLite3.
       
    90 ** The X value only changes when backwards compatibility is
       
    91 ** broken and we intend to never break backwards compatibility.
       
    92 ** The Y value is the minor version number and only changes when
       
    93 ** there are major feature enhancements that are forwards compatible
       
    94 ** but not backwards compatible.
       
    95 ** The Z value is the release number and is incremented with
       
    96 ** each release but resets back to 0 whenever Y is incremented.
       
    97 **
       
    98 ** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()].
       
    99 **
       
   100 ** Requirements: [H10011] [H10014]
       
   101 */
       
   102 #define SQLITE_VERSION         "3.6.12"
       
   103 #define SQLITE_VERSION_NUMBER  3006012
       
   104 
       
   105 /*
       
   106 ** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100>
       
   107 ** KEYWORDS: sqlite3_version
       
   108 **
       
   109 ** These features provide the same information as the [SQLITE_VERSION]
       
   110 ** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated
       
   111 ** with the library instead of the header file.  Cautious programmers might
       
   112 ** include a check in their application to verify that
       
   113 ** sqlite3_libversion_number() always returns the value
       
   114 ** [SQLITE_VERSION_NUMBER].
       
   115 **
       
   116 ** The sqlite3_libversion() function returns the same information as is
       
   117 ** in the sqlite3_version[] string constant.  The function is provided
       
   118 ** for use in DLLs since DLL users usually do not have direct access to string
       
   119 ** constants within the DLL.
       
   120 **
       
   121 ** Requirements: [H10021] [H10022] [H10023]
       
   122 */
       
   123 SQLITE_EXTERN const char sqlite3_version[];
       
   124 const char *sqlite3_libversion(void);
       
   125 int sqlite3_libversion_number(void);
       
   126 
       
   127 /*
       
   128 ** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100>
       
   129 **
       
   130 ** SQLite can be compiled with or without mutexes.  When
       
   131 ** the [SQLITE_THREADSAFE] C preprocessor macro 1 or 2, mutexes
       
   132 ** are enabled and SQLite is threadsafe.  When the
       
   133 ** [SQLITE_THREADSAFE] macro is 0, 
       
   134 ** the mutexes are omitted.  Without the mutexes, it is not safe
       
   135 ** to use SQLite concurrently from more than one thread.
       
   136 **
       
   137 ** Enabling mutexes incurs a measurable performance penalty.
       
   138 ** So if speed is of utmost importance, it makes sense to disable
       
   139 ** the mutexes.  But for maximum safety, mutexes should be enabled.
       
   140 ** The default behavior is for mutexes to be enabled.
       
   141 **
       
   142 ** This interface can be used by a program to make sure that the
       
   143 ** version of SQLite that it is linking against was compiled with
       
   144 ** the desired setting of the [SQLITE_THREADSAFE] macro.
       
   145 **
       
   146 ** This interface only reports on the compile-time mutex setting
       
   147 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
       
   148 ** SQLITE_THREADSAFE=1 then mutexes are enabled by default but
       
   149 ** can be fully or partially disabled using a call to [sqlite3_config()]
       
   150 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
       
   151 ** or [SQLITE_CONFIG_MUTEX].  The return value of this function shows
       
   152 ** only the default compile-time setting, not any run-time changes
       
   153 ** to that setting.
       
   154 **
       
   155 ** See the [threading mode] documentation for additional information.
       
   156 **
       
   157 ** Requirements: [H10101] [H10102]
       
   158 */
       
   159 int sqlite3_threadsafe(void);
       
   160 
       
   161 /*
       
   162 ** CAPI3REF: Database Connection Handle {H12000} <S40200>
       
   163 ** KEYWORDS: {database connection} {database connections}
       
   164 **
       
   165 ** Each open SQLite database is represented by a pointer to an instance of
       
   166 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
       
   167 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
       
   168 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
       
   169 ** is its destructor.  There are many other interfaces (such as
       
   170 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
       
   171 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
       
   172 ** sqlite3 object.
       
   173 */
       
   174 typedef struct sqlite3 sqlite3;
       
   175 
       
   176 /*
       
   177 ** CAPI3REF: 64-Bit Integer Types {H10200} <S10110>
       
   178 ** KEYWORDS: sqlite_int64 sqlite_uint64
       
   179 **
       
   180 ** Because there is no cross-platform way to specify 64-bit integer types
       
   181 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
       
   182 **
       
   183 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
       
   184 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
       
   185 ** compatibility only.
       
   186 **
       
   187 ** Requirements: [H10201] [H10202]
       
   188 */
       
   189 #ifdef SQLITE_INT64_TYPE
       
   190   typedef SQLITE_INT64_TYPE sqlite_int64;
       
   191   typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
       
   192 #elif defined(_MSC_VER) || defined(__BORLANDC__)
       
   193   typedef __int64 sqlite_int64;
       
   194   typedef unsigned __int64 sqlite_uint64;
       
   195 #else
       
   196   typedef long long int sqlite_int64;
       
   197   typedef unsigned long long int sqlite_uint64;
       
   198 #endif
       
   199 typedef sqlite_int64 sqlite3_int64;
       
   200 typedef sqlite_uint64 sqlite3_uint64;
       
   201 
       
   202 /*
       
   203 ** If compiling for a processor that lacks floating point support,
       
   204 ** substitute integer for floating-point.
       
   205 */
       
   206 #ifdef SQLITE_OMIT_FLOATING_POINT
       
   207 # define double sqlite3_int64
       
   208 #endif
       
   209 
       
   210 /*
       
   211 ** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200>
       
   212 **
       
   213 ** This routine is the destructor for the [sqlite3] object.
       
   214 **
       
   215 ** Applications should [sqlite3_finalize | finalize] all [prepared statements]
       
   216 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with
       
   217 ** the [sqlite3] object prior to attempting to close the object.
       
   218 ** The [sqlite3_next_stmt()] interface can be used to locate all
       
   219 ** [prepared statements] associated with a [database connection] if desired.
       
   220 ** Typical code might look like this:
       
   221 **
       
   222 ** <blockquote><pre>
       
   223 ** sqlite3_stmt *pStmt;
       
   224 ** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){
       
   225 ** &nbsp;   sqlite3_finalize(pStmt);
       
   226 ** }
       
   227 ** </pre></blockquote>
       
   228 **
       
   229 ** If [sqlite3_close()] is invoked while a transaction is open,
       
   230 ** the transaction is automatically rolled back.
       
   231 **
       
   232 ** The C parameter to [sqlite3_close(C)] must be either a NULL
       
   233 ** pointer or an [sqlite3] object pointer obtained
       
   234 ** from [sqlite3_open()], [sqlite3_open16()], or
       
   235 ** [sqlite3_open_v2()], and not previously closed.
       
   236 **
       
   237 ** Requirements:
       
   238 ** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019]
       
   239 */
       
   240 int sqlite3_close(sqlite3 *);
       
   241 
       
   242 /*
       
   243 ** The type for a callback function.
       
   244 ** This is legacy and deprecated.  It is included for historical
       
   245 ** compatibility and is not documented.
       
   246 */
       
   247 typedef int (*sqlite3_callback)(void*,int,char**, char**);
       
   248 
       
   249 /*
       
   250 ** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000>
       
   251 **
       
   252 ** The sqlite3_exec() interface is a convenient way of running one or more
       
   253 ** SQL statements without having to write a lot of C code.  The UTF-8 encoded
       
   254 ** SQL statements are passed in as the second parameter to sqlite3_exec().
       
   255 ** The statements are evaluated one by one until either an error or
       
   256 ** an interrupt is encountered, or until they are all done.  The 3rd parameter
       
   257 ** is an optional callback that is invoked once for each row of any query
       
   258 ** results produced by the SQL statements.  The 5th parameter tells where
       
   259 ** to write any error messages.
       
   260 **
       
   261 ** The error message passed back through the 5th parameter is held
       
   262 ** in memory obtained from [sqlite3_malloc()].  To avoid a memory leak,
       
   263 ** the calling application should call [sqlite3_free()] on any error
       
   264 ** message returned through the 5th parameter when it has finished using
       
   265 ** the error message.
       
   266 **
       
   267 ** If the SQL statement in the 2nd parameter is NULL or an empty string
       
   268 ** or a string containing only whitespace and comments, then no SQL
       
   269 ** statements are evaluated and the database is not changed.
       
   270 **
       
   271 ** The sqlite3_exec() interface is implemented in terms of
       
   272 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
       
   273 ** The sqlite3_exec() routine does nothing to the database that cannot be done
       
   274 ** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()].
       
   275 **
       
   276 ** The first parameter to [sqlite3_exec()] must be an valid and open
       
   277 ** [database connection].
       
   278 **
       
   279 ** The database connection must not be closed while
       
   280 ** [sqlite3_exec()] is running.
       
   281 **
       
   282 ** The calling function should use [sqlite3_free()] to free
       
   283 ** the memory that *errmsg is left pointing at once the error
       
   284 ** message is no longer needed.
       
   285 **
       
   286 ** The SQL statement text in the 2nd parameter to [sqlite3_exec()]
       
   287 ** must remain unchanged while [sqlite3_exec()] is running.
       
   288 **
       
   289 ** Requirements:
       
   290 ** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116]
       
   291 ** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138]
       
   292 */
       
   293 int sqlite3_exec(
       
   294   sqlite3*,                                  /* An open database */
       
   295   const char *sql,                           /* SQL to be evaluated */
       
   296   int (*callback)(void*,int,char**,char**),  /* Callback function */
       
   297   void *,                                    /* 1st argument to callback */
       
   298   char **errmsg                              /* Error msg written here */
       
   299 );
       
   300 
       
   301 /*
       
   302 ** CAPI3REF: Result Codes {H10210} <S10700>
       
   303 ** KEYWORDS: SQLITE_OK {error code} {error codes}
       
   304 ** KEYWORDS: {result code} {result codes}
       
   305 **
       
   306 ** Many SQLite functions return an integer result code from the set shown
       
   307 ** here in order to indicates success or failure.
       
   308 **
       
   309 ** New error codes may be added in future versions of SQLite.
       
   310 **
       
   311 ** See also: [SQLITE_IOERR_READ | extended result codes]
       
   312 */
       
   313 #define SQLITE_OK           0   /* Successful result */
       
   314 /* beginning-of-error-codes */
       
   315 #define SQLITE_ERROR        1   /* SQL error or missing database */
       
   316 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
       
   317 #define SQLITE_PERM         3   /* Access permission denied */
       
   318 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
       
   319 #define SQLITE_BUSY         5   /* The database file is locked */
       
   320 #define SQLITE_LOCKED       6   /* A table in the database is locked */
       
   321 #define SQLITE_NOMEM        7   /* A malloc() failed */
       
   322 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
       
   323 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
       
   324 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
       
   325 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
       
   326 #define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
       
   327 #define SQLITE_FULL        13   /* Insertion failed because database is full */
       
   328 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
       
   329 #define SQLITE_PROTOCOL    15   /* NOT USED. Database lock protocol error */
       
   330 #define SQLITE_EMPTY       16   /* Database is empty */
       
   331 #define SQLITE_SCHEMA      17   /* The database schema changed */
       
   332 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
       
   333 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
       
   334 #define SQLITE_MISMATCH    20   /* Data type mismatch */
       
   335 #define SQLITE_MISUSE      21   /* Library used incorrectly */
       
   336 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
       
   337 #define SQLITE_AUTH        23   /* Authorization denied */
       
   338 #define SQLITE_FORMAT      24   /* Auxiliary database format error */
       
   339 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
       
   340 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
       
   341 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
       
   342 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
       
   343 /* end-of-error-codes */
       
   344 
       
   345 /*
       
   346 ** CAPI3REF: Extended Result Codes {H10220} <S10700>
       
   347 ** KEYWORDS: {extended error code} {extended error codes}
       
   348 ** KEYWORDS: {extended result code} {extended result codes}
       
   349 **
       
   350 ** In its default configuration, SQLite API routines return one of 26 integer
       
   351 ** [SQLITE_OK | result codes].  However, experience has shown that many of
       
   352 ** these result codes are too coarse-grained.  They do not provide as
       
   353 ** much information about problems as programmers might like.  In an effort to
       
   354 ** address this, newer versions of SQLite (version 3.3.8 and later) include
       
   355 ** support for additional result codes that provide more detailed information
       
   356 ** about errors. The extended result codes are enabled or disabled
       
   357 ** on a per database connection basis using the
       
   358 ** [sqlite3_extended_result_codes()] API.
       
   359 **
       
   360 ** Some of the available extended result codes are listed here.
       
   361 ** One may expect the number of extended result codes will be expand
       
   362 ** over time.  Software that uses extended result codes should expect
       
   363 ** to see new result codes in future releases of SQLite.
       
   364 **
       
   365 ** The SQLITE_OK result code will never be extended.  It will always
       
   366 ** be exactly zero.
       
   367 */
       
   368 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
       
   369 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
       
   370 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
       
   371 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
       
   372 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
       
   373 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
       
   374 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
       
   375 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
       
   376 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
       
   377 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
       
   378 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
       
   379 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
       
   380 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
       
   381 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
       
   382 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
       
   383 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
       
   384 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
       
   385 
       
   386 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED | (1<<8) )
       
   387 
       
   388 /*
       
   389 ** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700>
       
   390 **
       
   391 ** These bit values are intended for use in the
       
   392 ** 3rd parameter to the [sqlite3_open_v2()] interface and
       
   393 ** in the 4th parameter to the xOpen method of the
       
   394 ** [sqlite3_vfs] object.
       
   395 */
       
   396 #define SQLITE_OPEN_READONLY         0x00000001
       
   397 #define SQLITE_OPEN_READWRITE        0x00000002
       
   398 #define SQLITE_OPEN_CREATE           0x00000004
       
   399 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008
       
   400 #define SQLITE_OPEN_EXCLUSIVE        0x00000010
       
   401 #define SQLITE_OPEN_AUTOPROXY        0x00000020
       
   402 #define SQLITE_OPEN_MAIN_DB          0x00000100
       
   403 #define SQLITE_OPEN_TEMP_DB          0x00000200
       
   404 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400
       
   405 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800
       
   406 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000
       
   407 #define SQLITE_OPEN_SUBJOURNAL       0x00002000
       
   408 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000
       
   409 #define SQLITE_OPEN_NOMUTEX          0x00008000
       
   410 #define SQLITE_OPEN_FULLMUTEX        0x00010000
       
   411 
       
   412 /*
       
   413 ** CAPI3REF: Device Characteristics {H10240} <H11120>
       
   414 **
       
   415 ** The xDeviceCapabilities method of the [sqlite3_io_methods]
       
   416 ** object returns an integer which is a vector of the these
       
   417 ** bit values expressing I/O characteristics of the mass storage
       
   418 ** device that holds the file that the [sqlite3_io_methods]
       
   419 ** refers to.
       
   420 **
       
   421 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
       
   422 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
       
   423 ** mean that writes of blocks that are nnn bytes in size and
       
   424 ** are aligned to an address which is an integer multiple of
       
   425 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
       
   426 ** that when data is appended to a file, the data is appended
       
   427 ** first then the size of the file is extended, never the other
       
   428 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
       
   429 ** information is written to disk in the same order as calls
       
   430 ** to xWrite().
       
   431 */
       
   432 #define SQLITE_IOCAP_ATOMIC          0x00000001
       
   433 #define SQLITE_IOCAP_ATOMIC512       0x00000002
       
   434 #define SQLITE_IOCAP_ATOMIC1K        0x00000004
       
   435 #define SQLITE_IOCAP_ATOMIC2K        0x00000008
       
   436 #define SQLITE_IOCAP_ATOMIC4K        0x00000010
       
   437 #define SQLITE_IOCAP_ATOMIC8K        0x00000020
       
   438 #define SQLITE_IOCAP_ATOMIC16K       0x00000040
       
   439 #define SQLITE_IOCAP_ATOMIC32K       0x00000080
       
   440 #define SQLITE_IOCAP_ATOMIC64K       0x00000100
       
   441 #define SQLITE_IOCAP_SAFE_APPEND     0x00000200
       
   442 #define SQLITE_IOCAP_SEQUENTIAL      0x00000400
       
   443 
       
   444 /*
       
   445 ** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310>
       
   446 **
       
   447 ** SQLite uses one of these integer values as the second
       
   448 ** argument to calls it makes to the xLock() and xUnlock() methods
       
   449 ** of an [sqlite3_io_methods] object.
       
   450 */
       
   451 #define SQLITE_LOCK_NONE          0
       
   452 #define SQLITE_LOCK_SHARED        1
       
   453 #define SQLITE_LOCK_RESERVED      2
       
   454 #define SQLITE_LOCK_PENDING       3
       
   455 #define SQLITE_LOCK_EXCLUSIVE     4
       
   456 
       
   457 /*
       
   458 ** CAPI3REF: Synchronization Type Flags {H10260} <H11120>
       
   459 **
       
   460 ** When SQLite invokes the xSync() method of an
       
   461 ** [sqlite3_io_methods] object it uses a combination of
       
   462 ** these integer values as the second argument.
       
   463 **
       
   464 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
       
   465 ** sync operation only needs to flush data to mass storage.  Inode
       
   466 ** information need not be flushed. The SQLITE_SYNC_NORMAL flag means
       
   467 ** to use normal fsync() semantics. The SQLITE_SYNC_FULL flag means
       
   468 ** to use Mac OS X style fullsync instead of fsync().
       
   469 */
       
   470 #define SQLITE_SYNC_NORMAL        0x00002
       
   471 #define SQLITE_SYNC_FULL          0x00003
       
   472 #define SQLITE_SYNC_DATAONLY      0x00010
       
   473 
       
   474 /*
       
   475 ** CAPI3REF: OS Interface Open File Handle {H11110} <S20110>
       
   476 **
       
   477 ** An [sqlite3_file] object represents an open file in the OS
       
   478 ** interface layer.  Individual OS interface implementations will
       
   479 ** want to subclass this object by appending additional fields
       
   480 ** for their own use.  The pMethods entry is a pointer to an
       
   481 ** [sqlite3_io_methods] object that defines methods for performing
       
   482 ** I/O operations on the open file.
       
   483 */
       
   484 typedef struct sqlite3_file sqlite3_file;
       
   485 struct sqlite3_file {
       
   486   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
       
   487 };
       
   488 
       
   489 /*
       
   490 ** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110>
       
   491 **
       
   492 ** Every file opened by the [sqlite3_vfs] xOpen method populates an
       
   493 ** [sqlite3_file] object (or, more commonly, a subclass of the
       
   494 ** [sqlite3_file] object) with a pointer to an instance of this object.
       
   495 ** This object defines the methods used to perform various operations
       
   496 ** against the open file represented by the [sqlite3_file] object.
       
   497 **
       
   498 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
       
   499 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
       
   500 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
       
   501 ** flag may be ORed in to indicate that only the data of the file
       
   502 ** and not its inode needs to be synced.
       
   503 **
       
   504 ** The integer values to xLock() and xUnlock() are one of
       
   505 ** <ul>
       
   506 ** <li> [SQLITE_LOCK_NONE],
       
   507 ** <li> [SQLITE_LOCK_SHARED],
       
   508 ** <li> [SQLITE_LOCK_RESERVED],
       
   509 ** <li> [SQLITE_LOCK_PENDING], or
       
   510 ** <li> [SQLITE_LOCK_EXCLUSIVE].
       
   511 ** </ul>
       
   512 ** xLock() increases the lock. xUnlock() decreases the lock.
       
   513 ** The xCheckReservedLock() method checks whether any database connection,
       
   514 ** either in this process or in some other process, is holding a RESERVED,
       
   515 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
       
   516 ** if such a lock exists and false otherwise.
       
   517 **
       
   518 ** The xFileControl() method is a generic interface that allows custom
       
   519 ** VFS implementations to directly control an open file using the
       
   520 ** [sqlite3_file_control()] interface.  The second "op" argument is an
       
   521 ** integer opcode.  The third argument is a generic pointer intended to
       
   522 ** point to a structure that may contain arguments or space in which to
       
   523 ** write return values.  Potential uses for xFileControl() might be
       
   524 ** functions to enable blocking locks with timeouts, to change the
       
   525 ** locking strategy (for example to use dot-file locks), to inquire
       
   526 ** about the status of a lock, or to break stale locks.  The SQLite
       
   527 ** core reserves all opcodes less than 100 for its own use.
       
   528 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available.
       
   529 ** Applications that define a custom xFileControl method should use opcodes
       
   530 ** greater than 100 to avoid conflicts.
       
   531 **
       
   532 ** The xSectorSize() method returns the sector size of the
       
   533 ** device that underlies the file.  The sector size is the
       
   534 ** minimum write that can be performed without disturbing
       
   535 ** other bytes in the file.  The xDeviceCharacteristics()
       
   536 ** method returns a bit vector describing behaviors of the
       
   537 ** underlying device:
       
   538 **
       
   539 ** <ul>
       
   540 ** <li> [SQLITE_IOCAP_ATOMIC]
       
   541 ** <li> [SQLITE_IOCAP_ATOMIC512]
       
   542 ** <li> [SQLITE_IOCAP_ATOMIC1K]
       
   543 ** <li> [SQLITE_IOCAP_ATOMIC2K]
       
   544 ** <li> [SQLITE_IOCAP_ATOMIC4K]
       
   545 ** <li> [SQLITE_IOCAP_ATOMIC8K]
       
   546 ** <li> [SQLITE_IOCAP_ATOMIC16K]
       
   547 ** <li> [SQLITE_IOCAP_ATOMIC32K]
       
   548 ** <li> [SQLITE_IOCAP_ATOMIC64K]
       
   549 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
       
   550 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
       
   551 ** </ul>
       
   552 **
       
   553 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
       
   554 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
       
   555 ** mean that writes of blocks that are nnn bytes in size and
       
   556 ** are aligned to an address which is an integer multiple of
       
   557 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
       
   558 ** that when data is appended to a file, the data is appended
       
   559 ** first then the size of the file is extended, never the other
       
   560 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
       
   561 ** information is written to disk in the same order as calls
       
   562 ** to xWrite().
       
   563 **
       
   564 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
       
   565 ** in the unread portions of the buffer with zeros.  A VFS that
       
   566 ** fails to zero-fill short reads might seem to work.  However,
       
   567 ** failure to zero-fill short reads will eventually lead to
       
   568 ** database corruption.
       
   569 */
       
   570 typedef struct sqlite3_io_methods sqlite3_io_methods;
       
   571 struct sqlite3_io_methods {
       
   572   int iVersion;
       
   573   int (*xClose)(sqlite3_file*);
       
   574   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
       
   575   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
       
   576   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
       
   577   int (*xSync)(sqlite3_file*, int flags);
       
   578   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
       
   579   int (*xLock)(sqlite3_file*, int);
       
   580   int (*xUnlock)(sqlite3_file*, int);
       
   581   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
       
   582   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
       
   583   int (*xSectorSize)(sqlite3_file*);
       
   584   int (*xDeviceCharacteristics)(sqlite3_file*);
       
   585   /* Additional methods may be added in future releases */
       
   586 };
       
   587 
       
   588 /*
       
   589 ** CAPI3REF: Standard File Control Opcodes {H11310} <S30800>
       
   590 **
       
   591 ** These integer constants are opcodes for the xFileControl method
       
   592 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
       
   593 ** interface.
       
   594 **
       
   595 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
       
   596 ** opcode causes the xFileControl method to write the current state of
       
   597 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
       
   598 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
       
   599 ** into an integer that the pArg argument points to. This capability
       
   600 ** is used during testing and only needs to be supported when SQLITE_TEST
       
   601 ** is defined.
       
   602 */
       
   603 #define SQLITE_FCNTL_LOCKSTATE        1
       
   604 #define SQLITE_GET_LOCKPROXYFILE      2
       
   605 #define SQLITE_SET_LOCKPROXYFILE      3
       
   606 #define SQLITE_LAST_ERRNO             4
       
   607 
       
   608 /*
       
   609 ** CAPI3REF: Mutex Handle {H17110} <S20130>
       
   610 **
       
   611 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
       
   612 ** abstract type for a mutex object.  The SQLite core never looks
       
   613 ** at the internal representation of an [sqlite3_mutex].  It only
       
   614 ** deals with pointers to the [sqlite3_mutex] object.
       
   615 **
       
   616 ** Mutexes are created using [sqlite3_mutex_alloc()].
       
   617 */
       
   618 typedef struct sqlite3_mutex sqlite3_mutex;
       
   619 
       
   620 /*
       
   621 ** CAPI3REF: OS Interface Object {H11140} <S20100>
       
   622 **
       
   623 ** An instance of the sqlite3_vfs object defines the interface between
       
   624 ** the SQLite core and the underlying operating system.  The "vfs"
       
   625 ** in the name of the object stands for "virtual file system".
       
   626 **
       
   627 ** The value of the iVersion field is initially 1 but may be larger in
       
   628 ** future versions of SQLite.  Additional fields may be appended to this
       
   629 ** object when the iVersion value is increased.  Note that the structure
       
   630 ** of the sqlite3_vfs object changes in the transaction between
       
   631 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
       
   632 ** modified.
       
   633 **
       
   634 ** The szOsFile field is the size of the subclassed [sqlite3_file]
       
   635 ** structure used by this VFS.  mxPathname is the maximum length of
       
   636 ** a pathname in this VFS.
       
   637 **
       
   638 ** Registered sqlite3_vfs objects are kept on a linked list formed by
       
   639 ** the pNext pointer.  The [sqlite3_vfs_register()]
       
   640 ** and [sqlite3_vfs_unregister()] interfaces manage this list
       
   641 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
       
   642 ** searches the list.  Neither the application code nor the VFS
       
   643 ** implementation should use the pNext pointer.
       
   644 **
       
   645 ** The pNext field is the only field in the sqlite3_vfs
       
   646 ** structure that SQLite will ever modify.  SQLite will only access
       
   647 ** or modify this field while holding a particular static mutex.
       
   648 ** The application should never modify anything within the sqlite3_vfs
       
   649 ** object once the object has been registered.
       
   650 **
       
   651 ** The zName field holds the name of the VFS module.  The name must
       
   652 ** be unique across all VFS modules.
       
   653 **
       
   654 ** SQLite will guarantee that the zFilename parameter to xOpen
       
   655 ** is either a NULL pointer or string obtained
       
   656 ** from xFullPathname().  SQLite further guarantees that
       
   657 ** the string will be valid and unchanged until xClose() is
       
   658 ** called. Because of the previous sentense,
       
   659 ** the [sqlite3_file] can safely store a pointer to the
       
   660 ** filename if it needs to remember the filename for some reason.
       
   661 ** If the zFilename parameter is xOpen is a NULL pointer then xOpen
       
   662 ** must invite its own temporary name for the file.  Whenever the 
       
   663 ** xFilename parameter is NULL it will also be the case that the
       
   664 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
       
   665 **
       
   666 ** The flags argument to xOpen() includes all bits set in
       
   667 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
       
   668 ** or [sqlite3_open16()] is used, then flags includes at least
       
   669 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 
       
   670 ** If xOpen() opens a file read-only then it sets *pOutFlags to
       
   671 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
       
   672 **
       
   673 ** SQLite will also add one of the following flags to the xOpen()
       
   674 ** call, depending on the object being opened:
       
   675 **
       
   676 ** <ul>
       
   677 ** <li>  [SQLITE_OPEN_MAIN_DB]
       
   678 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
       
   679 ** <li>  [SQLITE_OPEN_TEMP_DB]
       
   680 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
       
   681 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
       
   682 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
       
   683 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
       
   684 ** </ul>
       
   685 **
       
   686 ** The file I/O implementation can use the object type flags to
       
   687 ** change the way it deals with files.  For example, an application
       
   688 ** that does not care about crash recovery or rollback might make
       
   689 ** the open of a journal file a no-op.  Writes to this journal would
       
   690 ** also be no-ops, and any attempt to read the journal would return
       
   691 ** SQLITE_IOERR.  Or the implementation might recognize that a database
       
   692 ** file will be doing page-aligned sector reads and writes in a random
       
   693 ** order and set up its I/O subsystem accordingly.
       
   694 **
       
   695 ** SQLite might also add one of the following flags to the xOpen method:
       
   696 **
       
   697 ** <ul>
       
   698 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
       
   699 ** <li> [SQLITE_OPEN_EXCLUSIVE]
       
   700 ** </ul>
       
   701 **
       
   702 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
       
   703 ** deleted when it is closed.  The [SQLITE_OPEN_DELETEONCLOSE]
       
   704 ** will be set for TEMP  databases, journals and for subjournals.
       
   705 **
       
   706 ** The [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened
       
   707 ** for exclusive access.  This flag is set for all files except
       
   708 ** for the main database file.
       
   709 **
       
   710 ** At least szOsFile bytes of memory are allocated by SQLite
       
   711 ** to hold the  [sqlite3_file] structure passed as the third
       
   712 ** argument to xOpen.  The xOpen method does not have to
       
   713 ** allocate the structure; it should just fill it in.
       
   714 **
       
   715 ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
       
   716 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
       
   717 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
       
   718 ** to test whether a file is at least readable.   The file can be a
       
   719 ** directory.
       
   720 **
       
   721 ** SQLite will always allocate at least mxPathname+1 bytes for the
       
   722 ** output buffer xFullPathname.  The exact size of the output buffer
       
   723 ** is also passed as a parameter to both  methods. If the output buffer
       
   724 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
       
   725 ** handled as a fatal error by SQLite, vfs implementations should endeavor
       
   726 ** to prevent this by setting mxPathname to a sufficiently large value.
       
   727 **
       
   728 ** The xRandomness(), xSleep(), and xCurrentTime() interfaces
       
   729 ** are not strictly a part of the filesystem, but they are
       
   730 ** included in the VFS structure for completeness.
       
   731 ** The xRandomness() function attempts to return nBytes bytes
       
   732 ** of good-quality randomness into zOut.  The return value is
       
   733 ** the actual number of bytes of randomness obtained.
       
   734 ** The xSleep() method causes the calling thread to sleep for at
       
   735 ** least the number of microseconds given.  The xCurrentTime()
       
   736 ** method returns a Julian Day Number for the current date and time.
       
   737 **
       
   738 */
       
   739 typedef struct sqlite3_vfs sqlite3_vfs;
       
   740 struct sqlite3_vfs {
       
   741   int iVersion;            /* Structure version number */
       
   742   int szOsFile;            /* Size of subclassed sqlite3_file */
       
   743   int mxPathname;          /* Maximum file pathname length */
       
   744   sqlite3_vfs *pNext;      /* Next registered VFS */
       
   745   const char *zName;       /* Name of this virtual file system */
       
   746   void *pAppData;          /* Pointer to application-specific data */
       
   747   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
       
   748                int flags, int *pOutFlags);
       
   749   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
       
   750   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
       
   751   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
       
   752   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
       
   753   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
       
   754   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
       
   755   void (*xDlClose)(sqlite3_vfs*, void*);
       
   756   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
       
   757   int (*xSleep)(sqlite3_vfs*, int microseconds);
       
   758   int (*xCurrentTime)(sqlite3_vfs*, double*);
       
   759   int (*xGetLastError)(sqlite3_vfs*, int, char *);
       
   760   /* New fields may be appended in figure versions.  The iVersion
       
   761   ** value will increment whenever this happens. */
       
   762 };
       
   763 
       
   764 /*
       
   765 ** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140>
       
   766 **
       
   767 ** These integer constants can be used as the third parameter to
       
   768 ** the xAccess method of an [sqlite3_vfs] object. {END}  They determine
       
   769 ** what kind of permissions the xAccess method is looking for.
       
   770 ** With SQLITE_ACCESS_EXISTS, the xAccess method
       
   771 ** simply checks whether the file exists.
       
   772 ** With SQLITE_ACCESS_READWRITE, the xAccess method
       
   773 ** checks whether the file is both readable and writable.
       
   774 ** With SQLITE_ACCESS_READ, the xAccess method
       
   775 ** checks whether the file is readable.
       
   776 */
       
   777 #define SQLITE_ACCESS_EXISTS    0
       
   778 #define SQLITE_ACCESS_READWRITE 1
       
   779 #define SQLITE_ACCESS_READ      2
       
   780 
       
   781 /*
       
   782 ** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100>
       
   783 **
       
   784 ** The sqlite3_initialize() routine initializes the
       
   785 ** SQLite library.  The sqlite3_shutdown() routine
       
   786 ** deallocates any resources that were allocated by sqlite3_initialize().
       
   787 **
       
   788 ** A call to sqlite3_initialize() is an "effective" call if it is
       
   789 ** the first time sqlite3_initialize() is invoked during the lifetime of
       
   790 ** the process, or if it is the first time sqlite3_initialize() is invoked
       
   791 ** following a call to sqlite3_shutdown().  Only an effective call
       
   792 ** of sqlite3_initialize() does any initialization.  All other calls
       
   793 ** are harmless no-ops.
       
   794 **
       
   795 ** Among other things, sqlite3_initialize() shall invoke
       
   796 ** sqlite3_os_init().  Similarly, sqlite3_shutdown()
       
   797 ** shall invoke sqlite3_os_end().
       
   798 **
       
   799 ** The sqlite3_initialize() routine returns [SQLITE_OK] on success.
       
   800 ** If for some reason, sqlite3_initialize() is unable to initialize
       
   801 ** the library (perhaps it is unable to allocate a needed resource such
       
   802 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
       
   803 **
       
   804 ** The sqlite3_initialize() routine is called internally by many other
       
   805 ** SQLite interfaces so that an application usually does not need to
       
   806 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
       
   807 ** calls sqlite3_initialize() so the SQLite library will be automatically
       
   808 ** initialized when [sqlite3_open()] is called if it has not be initialized
       
   809 ** already.  However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
       
   810 ** compile-time option, then the automatic calls to sqlite3_initialize()
       
   811 ** are omitted and the application must call sqlite3_initialize() directly
       
   812 ** prior to using any other SQLite interface.  For maximum portability,
       
   813 ** it is recommended that applications always invoke sqlite3_initialize()
       
   814 ** directly prior to using any other SQLite interface.  Future releases
       
   815 ** of SQLite may require this.  In other words, the behavior exhibited
       
   816 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
       
   817 ** default behavior in some future release of SQLite.
       
   818 **
       
   819 ** The sqlite3_os_init() routine does operating-system specific
       
   820 ** initialization of the SQLite library.  The sqlite3_os_end()
       
   821 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
       
   822 ** performed by these routines include allocation or deallocation
       
   823 ** of static resources, initialization of global variables,
       
   824 ** setting up a default [sqlite3_vfs] module, or setting up
       
   825 ** a default configuration using [sqlite3_config()].
       
   826 **
       
   827 ** The application should never invoke either sqlite3_os_init()
       
   828 ** or sqlite3_os_end() directly.  The application should only invoke
       
   829 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
       
   830 ** interface is called automatically by sqlite3_initialize() and
       
   831 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
       
   832 ** implementations for sqlite3_os_init() and sqlite3_os_end()
       
   833 ** are built into SQLite when it is compiled for unix, windows, or os/2.
       
   834 ** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time
       
   835 ** option) the application must supply a suitable implementation for
       
   836 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
       
   837 ** implementation of sqlite3_os_init() or sqlite3_os_end()
       
   838 ** must return [SQLITE_OK] on success and some other [error code] upon
       
   839 ** failure.
       
   840 */
       
   841 int sqlite3_initialize(void);
       
   842 int sqlite3_shutdown(void);
       
   843 int sqlite3_os_init(void);
       
   844 int sqlite3_os_end(void);
       
   845 
       
   846 /*
       
   847 ** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200>
       
   848 ** EXPERIMENTAL
       
   849 **
       
   850 ** The sqlite3_config() interface is used to make global configuration
       
   851 ** changes to SQLite in order to tune SQLite to the specific needs of
       
   852 ** the application.  The default configuration is recommended for most
       
   853 ** applications and so this routine is usually not necessary.  It is
       
   854 ** provided to support rare applications with unusual needs.
       
   855 **
       
   856 ** The sqlite3_config() interface is not threadsafe.  The application
       
   857 ** must insure that no other SQLite interfaces are invoked by other
       
   858 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
       
   859 ** may only be invoked prior to library initialization using
       
   860 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
       
   861 ** Note, however, that sqlite3_config() can be called as part of the
       
   862 ** implementation of an application-defined [sqlite3_os_init()].
       
   863 **
       
   864 ** The first argument to sqlite3_config() is an integer
       
   865 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines
       
   866 ** what property of SQLite is to be configured.  Subsequent arguments
       
   867 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option]
       
   868 ** in the first argument.
       
   869 **
       
   870 ** When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
       
   871 ** If the option is unknown or SQLite is unable to set the option
       
   872 ** then this routine returns a non-zero [error code].
       
   873 **
       
   874 ** Requirements:
       
   875 ** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135]
       
   876 ** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159]
       
   877 ** [H14162] [H14165] [H14168]
       
   878 */
       
   879 SQLITE_EXPERIMENTAL int sqlite3_config(int, ...);
       
   880 
       
   881 /*
       
   882 ** CAPI3REF: Configure database connections  {H14200} <S20000>
       
   883 ** EXPERIMENTAL
       
   884 **
       
   885 ** The sqlite3_db_config() interface is used to make configuration
       
   886 ** changes to a [database connection].  The interface is similar to
       
   887 ** [sqlite3_config()] except that the changes apply to a single
       
   888 ** [database connection] (specified in the first argument).  The
       
   889 ** sqlite3_db_config() interface can only be used immediately after
       
   890 ** the database connection is created using [sqlite3_open()],
       
   891 ** [sqlite3_open16()], or [sqlite3_open_v2()].  
       
   892 **
       
   893 ** The second argument to sqlite3_db_config(D,V,...)  is the
       
   894 ** configuration verb - an integer code that indicates what
       
   895 ** aspect of the [database connection] is being configured.
       
   896 ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE].
       
   897 ** New verbs are likely to be added in future releases of SQLite.
       
   898 ** Additional arguments depend on the verb.
       
   899 **
       
   900 ** Requirements:
       
   901 ** [H14203] [H14206] [H14209] [H14212] [H14215]
       
   902 */
       
   903 SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);
       
   904 
       
   905 /*
       
   906 ** CAPI3REF: Memory Allocation Routines {H10155} <S20120>
       
   907 ** EXPERIMENTAL
       
   908 **
       
   909 ** An instance of this object defines the interface between SQLite
       
   910 ** and low-level memory allocation routines.
       
   911 **
       
   912 ** This object is used in only one place in the SQLite interface.
       
   913 ** A pointer to an instance of this object is the argument to
       
   914 ** [sqlite3_config()] when the configuration option is
       
   915 ** [SQLITE_CONFIG_MALLOC].  By creating an instance of this object
       
   916 ** and passing it to [sqlite3_config()] during configuration, an
       
   917 ** application can specify an alternative memory allocation subsystem
       
   918 ** for SQLite to use for all of its dynamic memory needs.
       
   919 **
       
   920 ** Note that SQLite comes with a built-in memory allocator that is
       
   921 ** perfectly adequate for the overwhelming majority of applications
       
   922 ** and that this object is only useful to a tiny minority of applications
       
   923 ** with specialized memory allocation requirements.  This object is
       
   924 ** also used during testing of SQLite in order to specify an alternative
       
   925 ** memory allocator that simulates memory out-of-memory conditions in
       
   926 ** order to verify that SQLite recovers gracefully from such
       
   927 ** conditions.
       
   928 **
       
   929 ** The xMalloc, xFree, and xRealloc methods must work like the
       
   930 ** malloc(), free(), and realloc() functions from the standard library.
       
   931 **
       
   932 ** xSize should return the allocated size of a memory allocation
       
   933 ** previously obtained from xMalloc or xRealloc.  The allocated size
       
   934 ** is always at least as big as the requested size but may be larger.
       
   935 **
       
   936 ** The xRoundup method returns what would be the allocated size of
       
   937 ** a memory allocation given a particular requested size.  Most memory
       
   938 ** allocators round up memory allocations at least to the next multiple
       
   939 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
       
   940 **
       
   941 ** The xInit method initializes the memory allocator.  (For example,
       
   942 ** it might allocate any require mutexes or initialize internal data
       
   943 ** structures.  The xShutdown method is invoked (indirectly) by
       
   944 ** [sqlite3_shutdown()] and should deallocate any resources acquired
       
   945 ** by xInit.  The pAppData pointer is used as the only parameter to
       
   946 ** xInit and xShutdown.
       
   947 */
       
   948 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
       
   949 struct sqlite3_mem_methods {
       
   950   void *(*xMalloc)(int);         /* Memory allocation function */
       
   951   void (*xFree)(void*);          /* Free a prior allocation */
       
   952   void *(*xRealloc)(void*,int);  /* Resize an allocation */
       
   953   int (*xSize)(void*);           /* Return the size of an allocation */
       
   954   int (*xRoundup)(int);          /* Round up request size to allocation size */
       
   955   int (*xInit)(void*);           /* Initialize the memory allocator */
       
   956   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
       
   957   void *pAppData;                /* Argument to xInit() and xShutdown() */
       
   958 };
       
   959 
       
   960 /*
       
   961 ** CAPI3REF: Configuration Options {H10160} <S20000>
       
   962 ** EXPERIMENTAL
       
   963 **
       
   964 ** These constants are the available integer configuration options that
       
   965 ** can be passed as the first argument to the [sqlite3_config()] interface.
       
   966 **
       
   967 ** New configuration options may be added in future releases of SQLite.
       
   968 ** Existing configuration options might be discontinued.  Applications
       
   969 ** should check the return code from [sqlite3_config()] to make sure that
       
   970 ** the call worked.  The [sqlite3_config()] interface will return a
       
   971 ** non-zero [error code] if a discontinued or unsupported configuration option
       
   972 ** is invoked.
       
   973 **
       
   974 ** <dl>
       
   975 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
       
   976 ** <dd>There are no arguments to this option.  This option disables
       
   977 ** all mutexing and puts SQLite into a mode where it can only be used
       
   978 ** by a single thread.</dd>
       
   979 **
       
   980 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt>
       
   981 ** <dd>There are no arguments to this option.  This option disables
       
   982 ** mutexing on [database connection] and [prepared statement] objects.
       
   983 ** The application is responsible for serializing access to
       
   984 ** [database connections] and [prepared statements].  But other mutexes
       
   985 ** are enabled so that SQLite will be safe to use in a multi-threaded
       
   986 ** environment as long as no two threads attempt to use the same
       
   987 ** [database connection] at the same time.  See the [threading mode]
       
   988 ** documentation for additional information.</dd>
       
   989 **
       
   990 ** <dt>SQLITE_CONFIG_SERIALIZED</dt>
       
   991 ** <dd>There are no arguments to this option.  This option enables
       
   992 ** all mutexes including the recursive
       
   993 ** mutexes on [database connection] and [prepared statement] objects.
       
   994 ** In this mode (which is the default when SQLite is compiled with
       
   995 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
       
   996 ** to [database connections] and [prepared statements] so that the
       
   997 ** application is free to use the same [database connection] or the
       
   998 ** same [prepared statement] in different threads at the same time.
       
   999 ** See the [threading mode] documentation for additional information.</dd>
       
  1000 **
       
  1001 ** <dt>SQLITE_CONFIG_MALLOC</dt>
       
  1002 ** <dd>This option takes a single argument which is a pointer to an
       
  1003 ** instance of the [sqlite3_mem_methods] structure.  The argument specifies
       
  1004 ** alternative low-level memory allocation routines to be used in place of
       
  1005 ** the memory allocation routines built into SQLite.</dd>
       
  1006 **
       
  1007 ** <dt>SQLITE_CONFIG_GETMALLOC</dt>
       
  1008 ** <dd>This option takes a single argument which is a pointer to an
       
  1009 ** instance of the [sqlite3_mem_methods] structure.  The [sqlite3_mem_methods]
       
  1010 ** structure is filled with the currently defined memory allocation routines.
       
  1011 ** This option can be used to overload the default memory allocation
       
  1012 ** routines with a wrapper that simulations memory allocation failure or
       
  1013 ** tracks memory usage, for example.</dd>
       
  1014 **
       
  1015 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt>
       
  1016 ** <dd>This option takes single argument of type int, interpreted as a 
       
  1017 ** boolean, which enables or disables the collection of memory allocation 
       
  1018 ** statistics. When disabled, the following SQLite interfaces become 
       
  1019 ** non-operational:
       
  1020 **   <ul>
       
  1021 **   <li> [sqlite3_memory_used()]
       
  1022 **   <li> [sqlite3_memory_highwater()]
       
  1023 **   <li> [sqlite3_soft_heap_limit()]
       
  1024 **   <li> [sqlite3_status()]
       
  1025 **   </ul>
       
  1026 ** </dd>
       
  1027 **
       
  1028 ** <dt>SQLITE_CONFIG_SCRATCH</dt>
       
  1029 ** <dd>This option specifies a static memory buffer that SQLite can use for
       
  1030 ** scratch memory.  There are three arguments:  A pointer to the memory, the
       
  1031 ** size of each scratch buffer (sz), and the number of buffers (N).  The sz
       
  1032 ** argument must be a multiple of 16. The sz parameter should be a few bytes
       
  1033 ** larger than the actual scratch space required due internal overhead.
       
  1034 ** The first
       
  1035 ** argument should point to an allocation of at least sz*N bytes of memory.
       
  1036 ** SQLite will use no more than one scratch buffer at once per thread, so
       
  1037 ** N should be set to the expected maximum number of threads.  The sz
       
  1038 ** parameter should be 6 times the size of the largest database page size.
       
  1039 ** Scratch buffers are used as part of the btree balance operation.  If
       
  1040 ** The btree balancer needs additional memory beyond what is provided by
       
  1041 ** scratch buffers or if no scratch buffer space is specified, then SQLite
       
  1042 ** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
       
  1043 **
       
  1044 ** <dt>SQLITE_CONFIG_PAGECACHE</dt>
       
  1045 ** <dd>This option specifies a static memory buffer that SQLite can use for
       
  1046 ** the database page cache with the default page cache implemenation.  
       
  1047 ** This configuration should not be used if an application-define page
       
  1048 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option.
       
  1049 ** There are three arguments to this option: A pointer to the
       
  1050 ** memory, the size of each page buffer (sz), and the number of pages (N).
       
  1051 ** The sz argument must be a power of two between 512 and 32768.  The first
       
  1052 ** argument should point to an allocation of at least sz*N bytes of memory.
       
  1053 ** SQLite will use the memory provided by the first argument to satisfy its
       
  1054 ** memory needs for the first N pages that it adds to cache.  If additional
       
  1055 ** page cache memory is needed beyond what is provided by this option, then
       
  1056 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.
       
  1057 ** The implementation might use one or more of the N buffers to hold 
       
  1058 ** memory accounting information. </dd>
       
  1059 **
       
  1060 ** <dt>SQLITE_CONFIG_HEAP</dt>
       
  1061 ** <dd>This option specifies a static memory buffer that SQLite will use
       
  1062 ** for all of its dynamic memory allocation needs beyond those provided
       
  1063 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
       
  1064 ** There are three arguments: A pointer to the memory, the number of
       
  1065 ** bytes in the memory buffer, and the minimum allocation size.  If
       
  1066 ** the first pointer (the memory pointer) is NULL, then SQLite reverts
       
  1067 ** to using its default memory allocator (the system malloc() implementation),
       
  1068 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  If the
       
  1069 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
       
  1070 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
       
  1071 ** allocator is engaged to handle all of SQLites memory allocation needs.</dd>
       
  1072 **
       
  1073 ** <dt>SQLITE_CONFIG_MUTEX</dt>
       
  1074 ** <dd>This option takes a single argument which is a pointer to an
       
  1075 ** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
       
  1076 ** alternative low-level mutex routines to be used in place
       
  1077 ** the mutex routines built into SQLite.</dd>
       
  1078 **
       
  1079 ** <dt>SQLITE_CONFIG_GETMUTEX</dt>
       
  1080 ** <dd>This option takes a single argument which is a pointer to an
       
  1081 ** instance of the [sqlite3_mutex_methods] structure.  The
       
  1082 ** [sqlite3_mutex_methods]
       
  1083 ** structure is filled with the currently defined mutex routines.
       
  1084 ** This option can be used to overload the default mutex allocation
       
  1085 ** routines with a wrapper used to track mutex usage for performance
       
  1086 ** profiling or testing, for example.</dd>
       
  1087 **
       
  1088 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
       
  1089 ** <dd>This option takes two arguments that determine the default
       
  1090 ** memory allcation lookaside optimization.  The first argument is the
       
  1091 ** size of each lookaside buffer slot and the second is the number of
       
  1092 ** slots allocated to each database connection.</dd>
       
  1093 **
       
  1094 ** <dt>SQLITE_CONFIG_PCACHE</dt>
       
  1095 ** <dd>This option takes a single argument which is a pointer to
       
  1096 ** an [sqlite3_pcache_methods] object.  This object specifies the interface
       
  1097 ** to a custom page cache implementation.  SQLite makes a copy of the
       
  1098 ** object and uses it for page cache memory allocations.</dd>
       
  1099 **
       
  1100 ** <dt>SQLITE_CONFIG_GETPCACHE</dt>
       
  1101 ** <dd>This option takes a single argument which is a pointer to an
       
  1102 ** [sqlite3_pcache_methods] object.  SQLite copies of the current
       
  1103 ** page cache implementation into that object.</dd>
       
  1104 **
       
  1105 ** </dl>
       
  1106 */
       
  1107 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
       
  1108 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
       
  1109 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
       
  1110 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
       
  1111 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
       
  1112 #define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
       
  1113 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
       
  1114 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
       
  1115 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
       
  1116 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
       
  1117 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
       
  1118 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
       
  1119 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
       
  1120 #define SQLITE_CONFIG_PCACHE       14  /* sqlite3_pcache_methods* */
       
  1121 #define SQLITE_CONFIG_GETPCACHE    15  /* sqlite3_pcache_methods* */
       
  1122 
       
  1123 /*
       
  1124 ** CAPI3REF: Configuration Options {H10170} <S20000>
       
  1125 ** EXPERIMENTAL
       
  1126 **
       
  1127 ** These constants are the available integer configuration options that
       
  1128 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
       
  1129 **
       
  1130 ** New configuration options may be added in future releases of SQLite.
       
  1131 ** Existing configuration options might be discontinued.  Applications
       
  1132 ** should check the return code from [sqlite3_db_config()] to make sure that
       
  1133 ** the call worked.  The [sqlite3_db_config()] interface will return a
       
  1134 ** non-zero [error code] if a discontinued or unsupported configuration option
       
  1135 ** is invoked.
       
  1136 **
       
  1137 ** <dl>
       
  1138 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
       
  1139 ** <dd>This option takes three additional arguments that determine the 
       
  1140 ** [lookaside memory allocator] configuration for the [database connection].
       
  1141 ** The first argument (the third parameter to [sqlite3_db_config()] is a
       
  1142 ** pointer to a memory buffer to use for lookaside memory.  The first
       
  1143 ** argument may be NULL in which case SQLite will allocate the lookaside
       
  1144 ** buffer itself using [sqlite3_malloc()].  The second argument is the
       
  1145 ** size of each lookaside buffer slot and the third argument is the number of
       
  1146 ** slots.  The size of the buffer in the first argument must be greater than
       
  1147 ** or equal to the product of the second and third arguments.</dd>
       
  1148 **
       
  1149 ** </dl>
       
  1150 */
       
  1151 #define SQLITE_DBCONFIG_LOOKASIDE    1001  /* void* int int */
       
  1152 
       
  1153 
       
  1154 /*
       
  1155 ** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
       
  1156 **
       
  1157 ** The sqlite3_extended_result_codes() routine enables or disables the
       
  1158 ** [extended result codes] feature of SQLite. The extended result
       
  1159 ** codes are disabled by default for historical compatibility considerations.
       
  1160 **
       
  1161 ** Requirements:
       
  1162 ** [H12201] [H12202]
       
  1163 */
       
  1164 int sqlite3_extended_result_codes(sqlite3*, int onoff);
       
  1165 
       
  1166 /*
       
  1167 ** CAPI3REF: Last Insert Rowid {H12220} <S10700>
       
  1168 **
       
  1169 ** Each entry in an SQLite table has a unique 64-bit signed
       
  1170 ** integer key called the [ROWID | "rowid"]. The rowid is always available
       
  1171 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
       
  1172 ** names are not also used by explicitly declared columns. If
       
  1173 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
       
  1174 ** is another alias for the rowid.
       
  1175 **
       
  1176 ** This routine returns the [rowid] of the most recent
       
  1177 ** successful [INSERT] into the database from the [database connection]
       
  1178 ** in the first argument.  If no successful [INSERT]s
       
  1179 ** have ever occurred on that database connection, zero is returned.
       
  1180 **
       
  1181 ** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted
       
  1182 ** row is returned by this routine as long as the trigger is running.
       
  1183 ** But once the trigger terminates, the value returned by this routine
       
  1184 ** reverts to the last value inserted before the trigger fired.
       
  1185 **
       
  1186 ** An [INSERT] that fails due to a constraint violation is not a
       
  1187 ** successful [INSERT] and does not change the value returned by this
       
  1188 ** routine.  Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
       
  1189 ** and INSERT OR ABORT make no changes to the return value of this
       
  1190 ** routine when their insertion fails.  When INSERT OR REPLACE
       
  1191 ** encounters a constraint violation, it does not fail.  The
       
  1192 ** INSERT continues to completion after deleting rows that caused
       
  1193 ** the constraint problem so INSERT OR REPLACE will always change
       
  1194 ** the return value of this interface.
       
  1195 **
       
  1196 ** For the purposes of this routine, an [INSERT] is considered to
       
  1197 ** be successful even if it is subsequently rolled back.
       
  1198 **
       
  1199 ** Requirements:
       
  1200 ** [H12221] [H12223]
       
  1201 **
       
  1202 ** If a separate thread performs a new [INSERT] on the same
       
  1203 ** database connection while the [sqlite3_last_insert_rowid()]
       
  1204 ** function is running and thus changes the last insert [rowid],
       
  1205 ** then the value returned by [sqlite3_last_insert_rowid()] is
       
  1206 ** unpredictable and might not equal either the old or the new
       
  1207 ** last insert [rowid].
       
  1208 */
       
  1209 sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
       
  1210 
       
  1211 /*
       
  1212 ** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
       
  1213 **
       
  1214 ** This function returns the number of database rows that were changed
       
  1215 ** or inserted or deleted by the most recently completed SQL statement
       
  1216 ** on the [database connection] specified by the first parameter.
       
  1217 ** Only changes that are directly specified by the [INSERT], [UPDATE],
       
  1218 ** or [DELETE] statement are counted.  Auxiliary changes caused by
       
  1219 ** triggers are not counted. Use the [sqlite3_total_changes()] function
       
  1220 ** to find the total number of changes including changes caused by triggers.
       
  1221 **
       
  1222 ** A "row change" is a change to a single row of a single table
       
  1223 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
       
  1224 ** are changed as side effects of REPLACE constraint resolution,
       
  1225 ** rollback, ABORT processing, DROP TABLE, or by any other
       
  1226 ** mechanisms do not count as direct row changes.
       
  1227 **
       
  1228 ** A "trigger context" is a scope of execution that begins and
       
  1229 ** ends with the script of a trigger.  Most SQL statements are
       
  1230 ** evaluated outside of any trigger.  This is the "top level"
       
  1231 ** trigger context.  If a trigger fires from the top level, a
       
  1232 ** new trigger context is entered for the duration of that one
       
  1233 ** trigger.  Subtriggers create subcontexts for their duration.
       
  1234 **
       
  1235 ** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
       
  1236 ** not create a new trigger context.
       
  1237 **
       
  1238 ** This function returns the number of direct row changes in the
       
  1239 ** most recent INSERT, UPDATE, or DELETE statement within the same
       
  1240 ** trigger context.
       
  1241 **
       
  1242 ** Thus, when called from the top level, this function returns the
       
  1243 ** number of changes in the most recent INSERT, UPDATE, or DELETE
       
  1244 ** that also occurred at the top level.  Within the body of a trigger,
       
  1245 ** the sqlite3_changes() interface can be called to find the number of
       
  1246 ** changes in the most recently completed INSERT, UPDATE, or DELETE
       
  1247 ** statement within the body of the same trigger.
       
  1248 ** However, the number returned does not include changes
       
  1249 ** caused by subtriggers since those have their own context.
       
  1250 **
       
  1251 ** SQLite implements the command "DELETE FROM table" without a WHERE clause
       
  1252 ** by dropping and recreating the table.  Doing so is much faster than going
       
  1253 ** through and deleting individual elements from the table.  Because of this
       
  1254 ** optimization, the deletions in "DELETE FROM table" are not row changes and
       
  1255 ** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
       
  1256 ** functions, regardless of the number of elements that were originally
       
  1257 ** in the table.  To get an accurate count of the number of rows deleted, use
       
  1258 ** "DELETE FROM table WHERE 1" instead.  Or recompile using the
       
  1259 ** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the
       
  1260 ** optimization on all queries.
       
  1261 **
       
  1262 ** Requirements:
       
  1263 ** [H12241] [H12243]
       
  1264 **
       
  1265 ** If a separate thread makes changes on the same database connection
       
  1266 ** while [sqlite3_changes()] is running then the value returned
       
  1267 ** is unpredictable and not meaningful.
       
  1268 */
       
  1269 int sqlite3_changes(sqlite3*);
       
  1270 
       
  1271 /*
       
  1272 ** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
       
  1273 **
       
  1274 ** This function returns the number of row changes caused by INSERT,
       
  1275 ** UPDATE or DELETE statements since the [database connection] was opened.
       
  1276 ** The count includes all changes from all trigger contexts.  However,
       
  1277 ** the count does not include changes used to implement REPLACE constraints,
       
  1278 ** do rollbacks or ABORT processing, or DROP table processing.
       
  1279 ** The changes are counted as soon as the statement that makes them is
       
  1280 ** completed (when the statement handle is passed to [sqlite3_reset()] or
       
  1281 ** [sqlite3_finalize()]).
       
  1282 **
       
  1283 ** SQLite implements the command "DELETE FROM table" without a WHERE clause
       
  1284 ** by dropping and recreating the table.  (This is much faster than going
       
  1285 ** through and deleting individual elements from the table.)  Because of this
       
  1286 ** optimization, the deletions in "DELETE FROM table" are not row changes and
       
  1287 ** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
       
  1288 ** functions, regardless of the number of elements that were originally
       
  1289 ** in the table.  To get an accurate count of the number of rows deleted, use
       
  1290 ** "DELETE FROM table WHERE 1" instead.   Or recompile using the
       
  1291 ** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the
       
  1292 ** optimization on all queries.
       
  1293 **
       
  1294 ** See also the [sqlite3_changes()] interface.
       
  1295 **
       
  1296 ** Requirements:
       
  1297 ** [H12261] [H12263]
       
  1298 **
       
  1299 ** If a separate thread makes changes on the same database connection
       
  1300 ** while [sqlite3_total_changes()] is running then the value
       
  1301 ** returned is unpredictable and not meaningful.
       
  1302 */
       
  1303 int sqlite3_total_changes(sqlite3*);
       
  1304 
       
  1305 /*
       
  1306 ** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500>
       
  1307 **
       
  1308 ** This function causes any pending database operation to abort and
       
  1309 ** return at its earliest opportunity. This routine is typically
       
  1310 ** called in response to a user action such as pressing "Cancel"
       
  1311 ** or Ctrl-C where the user wants a long query operation to halt
       
  1312 ** immediately.
       
  1313 **
       
  1314 ** It is safe to call this routine from a thread different from the
       
  1315 ** thread that is currently running the database operation.  But it
       
  1316 ** is not safe to call this routine with a [database connection] that
       
  1317 ** is closed or might close before sqlite3_interrupt() returns.
       
  1318 **
       
  1319 ** If an SQL operation is very nearly finished at the time when
       
  1320 ** sqlite3_interrupt() is called, then it might not have an opportunity
       
  1321 ** to be interrupted and might continue to completion.
       
  1322 **
       
  1323 ** An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
       
  1324 ** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
       
  1325 ** that is inside an explicit transaction, then the entire transaction
       
  1326 ** will be rolled back automatically.
       
  1327 **
       
  1328 ** A call to sqlite3_interrupt() has no effect on SQL statements
       
  1329 ** that are started after sqlite3_interrupt() returns.
       
  1330 **
       
  1331 ** Requirements:
       
  1332 ** [H12271] [H12272]
       
  1333 **
       
  1334 ** If the database connection closes while [sqlite3_interrupt()]
       
  1335 ** is running then bad things will likely happen.
       
  1336 */
       
  1337 void sqlite3_interrupt(sqlite3*);
       
  1338 
       
  1339 /*
       
  1340 ** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200>
       
  1341 **
       
  1342 ** These routines are useful for command-line input to determine if the
       
  1343 ** currently entered text seems to form complete a SQL statement or
       
  1344 ** if additional input is needed before sending the text into
       
  1345 ** SQLite for parsing.  These routines return true if the input string
       
  1346 ** appears to be a complete SQL statement.  A statement is judged to be
       
  1347 ** complete if it ends with a semicolon token and is not a fragment of a
       
  1348 ** CREATE TRIGGER statement.  Semicolons that are embedded within
       
  1349 ** string literals or quoted identifier names or comments are not
       
  1350 ** independent tokens (they are part of the token in which they are
       
  1351 ** embedded) and thus do not count as a statement terminator.
       
  1352 **
       
  1353 ** These routines do not parse the SQL statements thus
       
  1354 ** will not detect syntactically incorrect SQL.
       
  1355 **
       
  1356 ** Requirements: [H10511] [H10512]
       
  1357 **
       
  1358 ** The input to [sqlite3_complete()] must be a zero-terminated
       
  1359 ** UTF-8 string.
       
  1360 **
       
  1361 ** The input to [sqlite3_complete16()] must be a zero-terminated
       
  1362 ** UTF-16 string in native byte order.
       
  1363 */
       
  1364 int sqlite3_complete(const char *sql);
       
  1365 int sqlite3_complete16(const void *sql);
       
  1366 
       
  1367 /*
       
  1368 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400>
       
  1369 **
       
  1370 ** This routine sets a callback function that might be invoked whenever
       
  1371 ** an attempt is made to open a database table that another thread
       
  1372 ** or process has locked.
       
  1373 **
       
  1374 ** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]
       
  1375 ** is returned immediately upon encountering the lock. If the busy callback
       
  1376 ** is not NULL, then the callback will be invoked with two arguments.
       
  1377 **
       
  1378 ** The first argument to the handler is a copy of the void* pointer which
       
  1379 ** is the third argument to sqlite3_busy_handler().  The second argument to
       
  1380 ** the handler callback is the number of times that the busy handler has
       
  1381 ** been invoked for this locking event.  If the
       
  1382 ** busy callback returns 0, then no additional attempts are made to
       
  1383 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.
       
  1384 ** If the callback returns non-zero, then another attempt
       
  1385 ** is made to open the database for reading and the cycle repeats.
       
  1386 **
       
  1387 ** The presence of a busy handler does not guarantee that it will be invoked
       
  1388 ** when there is lock contention. If SQLite determines that invoking the busy
       
  1389 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
       
  1390 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler.
       
  1391 ** Consider a scenario where one process is holding a read lock that
       
  1392 ** it is trying to promote to a reserved lock and
       
  1393 ** a second process is holding a reserved lock that it is trying
       
  1394 ** to promote to an exclusive lock.  The first process cannot proceed
       
  1395 ** because it is blocked by the second and the second process cannot
       
  1396 ** proceed because it is blocked by the first.  If both processes
       
  1397 ** invoke the busy handlers, neither will make any progress.  Therefore,
       
  1398 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
       
  1399 ** will induce the first process to release its read lock and allow
       
  1400 ** the second process to proceed.
       
  1401 **
       
  1402 ** The default busy callback is NULL.
       
  1403 **
       
  1404 ** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]
       
  1405 ** when SQLite is in the middle of a large transaction where all the
       
  1406 ** changes will not fit into the in-memory cache.  SQLite will
       
  1407 ** already hold a RESERVED lock on the database file, but it needs
       
  1408 ** to promote this lock to EXCLUSIVE so that it can spill cache
       
  1409 ** pages into the database file without harm to concurrent
       
  1410 ** readers.  If it is unable to promote the lock, then the in-memory
       
  1411 ** cache will be left in an inconsistent state and so the error
       
  1412 ** code is promoted from the relatively benign [SQLITE_BUSY] to
       
  1413 ** the more severe [SQLITE_IOERR_BLOCKED].  This error code promotion
       
  1414 ** forces an automatic rollback of the changes.  See the
       
  1415 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">
       
  1416 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why
       
  1417 ** this is important.
       
  1418 **
       
  1419 ** There can only be a single busy handler defined for each
       
  1420 ** [database connection].  Setting a new busy handler clears any
       
  1421 ** previously set handler.  Note that calling [sqlite3_busy_timeout()]
       
  1422 ** will also set or clear the busy handler.
       
  1423 **
       
  1424 ** The busy callback should not take any actions which modify the
       
  1425 ** database connection that invoked the busy handler.  Any such actions
       
  1426 ** result in undefined behavior.
       
  1427 ** 
       
  1428 ** Requirements:
       
  1429 ** [H12311] [H12312] [H12314] [H12316] [H12318]
       
  1430 **
       
  1431 ** A busy handler must not close the database connection
       
  1432 ** or [prepared statement] that invoked the busy handler.
       
  1433 */
       
  1434 int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
       
  1435 
       
  1436 /*
       
  1437 ** CAPI3REF: Set A Busy Timeout {H12340} <S40410>
       
  1438 **
       
  1439 ** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
       
  1440 ** for a specified amount of time when a table is locked.  The handler
       
  1441 ** will sleep multiple times until at least "ms" milliseconds of sleeping
       
  1442 ** have accumulated. {H12343} After "ms" milliseconds of sleeping,
       
  1443 ** the handler returns 0 which causes [sqlite3_step()] to return
       
  1444 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED].
       
  1445 **
       
  1446 ** Calling this routine with an argument less than or equal to zero
       
  1447 ** turns off all busy handlers.
       
  1448 **
       
  1449 ** There can only be a single busy handler for a particular
       
  1450 ** [database connection] any any given moment.  If another busy handler
       
  1451 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
       
  1452 ** this routine, that other busy handler is cleared.
       
  1453 **
       
  1454 ** Requirements:
       
  1455 ** [H12341] [H12343] [H12344]
       
  1456 */
       
  1457 int sqlite3_busy_timeout(sqlite3*, int ms);
       
  1458 
       
  1459 /*
       
  1460 ** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000>
       
  1461 **
       
  1462 ** Definition: A <b>result table</b> is memory data structure created by the
       
  1463 ** [sqlite3_get_table()] interface.  A result table records the
       
  1464 ** complete query results from one or more queries.
       
  1465 **
       
  1466 ** The table conceptually has a number of rows and columns.  But
       
  1467 ** these numbers are not part of the result table itself.  These
       
  1468 ** numbers are obtained separately.  Let N be the number of rows
       
  1469 ** and M be the number of columns.
       
  1470 **
       
  1471 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
       
  1472 ** There are (N+1)*M elements in the array.  The first M pointers point
       
  1473 ** to zero-terminated strings that  contain the names of the columns.
       
  1474 ** The remaining entries all point to query results.  NULL values result
       
  1475 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
       
  1476 ** string representation as returned by [sqlite3_column_text()].
       
  1477 **
       
  1478 ** A result table might consist of one or more memory allocations.
       
  1479 ** It is not safe to pass a result table directly to [sqlite3_free()].
       
  1480 ** A result table should be deallocated using [sqlite3_free_table()].
       
  1481 **
       
  1482 ** As an example of the result table format, suppose a query result
       
  1483 ** is as follows:
       
  1484 **
       
  1485 ** <blockquote><pre>
       
  1486 **        Name        | Age
       
  1487 **        -----------------------
       
  1488 **        Alice       | 43
       
  1489 **        Bob         | 28
       
  1490 **        Cindy       | 21
       
  1491 ** </pre></blockquote>
       
  1492 **
       
  1493 ** There are two column (M==2) and three rows (N==3).  Thus the
       
  1494 ** result table has 8 entries.  Suppose the result table is stored
       
  1495 ** in an array names azResult.  Then azResult holds this content:
       
  1496 **
       
  1497 ** <blockquote><pre>
       
  1498 **        azResult&#91;0] = "Name";
       
  1499 **        azResult&#91;1] = "Age";
       
  1500 **        azResult&#91;2] = "Alice";
       
  1501 **        azResult&#91;3] = "43";
       
  1502 **        azResult&#91;4] = "Bob";
       
  1503 **        azResult&#91;5] = "28";
       
  1504 **        azResult&#91;6] = "Cindy";
       
  1505 **        azResult&#91;7] = "21";
       
  1506 ** </pre></blockquote>
       
  1507 **
       
  1508 ** The sqlite3_get_table() function evaluates one or more
       
  1509 ** semicolon-separated SQL statements in the zero-terminated UTF-8
       
  1510 ** string of its 2nd parameter.  It returns a result table to the
       
  1511 ** pointer given in its 3rd parameter.
       
  1512 **
       
  1513 ** After the calling function has finished using the result, it should
       
  1514 ** pass the pointer to the result table to sqlite3_free_table() in order to
       
  1515 ** release the memory that was malloced.  Because of the way the
       
  1516 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
       
  1517 ** function must not try to call [sqlite3_free()] directly.  Only
       
  1518 ** [sqlite3_free_table()] is able to release the memory properly and safely.
       
  1519 **
       
  1520 ** The sqlite3_get_table() interface is implemented as a wrapper around
       
  1521 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
       
  1522 ** to any internal data structures of SQLite.  It uses only the public
       
  1523 ** interface defined here.  As a consequence, errors that occur in the
       
  1524 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
       
  1525 ** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()].
       
  1526 **
       
  1527 ** Requirements:
       
  1528 ** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382]
       
  1529 */
       
  1530 int sqlite3_get_table(
       
  1531   sqlite3 *db,          /* An open database */
       
  1532   const char *zSql,     /* SQL to be evaluated */
       
  1533   char ***pazResult,    /* Results of the query */
       
  1534   int *pnRow,           /* Number of result rows written here */
       
  1535   int *pnColumn,        /* Number of result columns written here */
       
  1536   char **pzErrmsg       /* Error msg written here */
       
  1537 );
       
  1538 void sqlite3_free_table(char **result);
       
  1539 
       
  1540 /*
       
  1541 ** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000>
       
  1542 **
       
  1543 ** These routines are workalikes of the "printf()" family of functions
       
  1544 ** from the standard C library.
       
  1545 **
       
  1546 ** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
       
  1547 ** results into memory obtained from [sqlite3_malloc()].
       
  1548 ** The strings returned by these two routines should be
       
  1549 ** released by [sqlite3_free()].  Both routines return a
       
  1550 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
       
  1551 ** memory to hold the resulting string.
       
  1552 **
       
  1553 ** In sqlite3_snprintf() routine is similar to "snprintf()" from
       
  1554 ** the standard C library.  The result is written into the
       
  1555 ** buffer supplied as the second parameter whose size is given by
       
  1556 ** the first parameter. Note that the order of the
       
  1557 ** first two parameters is reversed from snprintf().  This is an
       
  1558 ** historical accident that cannot be fixed without breaking
       
  1559 ** backwards compatibility.  Note also that sqlite3_snprintf()
       
  1560 ** returns a pointer to its buffer instead of the number of
       
  1561 ** characters actually written into the buffer.  We admit that
       
  1562 ** the number of characters written would be a more useful return
       
  1563 ** value but we cannot change the implementation of sqlite3_snprintf()
       
  1564 ** now without breaking compatibility.
       
  1565 **
       
  1566 ** As long as the buffer size is greater than zero, sqlite3_snprintf()
       
  1567 ** guarantees that the buffer is always zero-terminated.  The first
       
  1568 ** parameter "n" is the total size of the buffer, including space for
       
  1569 ** the zero terminator.  So the longest string that can be completely
       
  1570 ** written will be n-1 characters.
       
  1571 **
       
  1572 ** These routines all implement some additional formatting
       
  1573 ** options that are useful for constructing SQL statements.
       
  1574 ** All of the usual printf() formatting options apply.  In addition, there
       
  1575 ** is are "%q", "%Q", and "%z" options.
       
  1576 **
       
  1577 ** The %q option works like %s in that it substitutes a null-terminated
       
  1578 ** string from the argument list.  But %q also doubles every '\'' character.
       
  1579 ** %q is designed for use inside a string literal.  By doubling each '\''
       
  1580 ** character it escapes that character and allows it to be inserted into
       
  1581 ** the string.
       
  1582 **
       
  1583 ** For example, assume the string variable zText contains text as follows:
       
  1584 **
       
  1585 ** <blockquote><pre>
       
  1586 **  char *zText = "It's a happy day!";
       
  1587 ** </pre></blockquote>
       
  1588 **
       
  1589 ** One can use this text in an SQL statement as follows:
       
  1590 **
       
  1591 ** <blockquote><pre>
       
  1592 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
       
  1593 **  sqlite3_exec(db, zSQL, 0, 0, 0);
       
  1594 **  sqlite3_free(zSQL);
       
  1595 ** </pre></blockquote>
       
  1596 **
       
  1597 ** Because the %q format string is used, the '\'' character in zText
       
  1598 ** is escaped and the SQL generated is as follows:
       
  1599 **
       
  1600 ** <blockquote><pre>
       
  1601 **  INSERT INTO table1 VALUES('It''s a happy day!')
       
  1602 ** </pre></blockquote>
       
  1603 **
       
  1604 ** This is correct.  Had we used %s instead of %q, the generated SQL
       
  1605 ** would have looked like this:
       
  1606 **
       
  1607 ** <blockquote><pre>
       
  1608 **  INSERT INTO table1 VALUES('It's a happy day!');
       
  1609 ** </pre></blockquote>
       
  1610 **
       
  1611 ** This second example is an SQL syntax error.  As a general rule you should
       
  1612 ** always use %q instead of %s when inserting text into a string literal.
       
  1613 **
       
  1614 ** The %Q option works like %q except it also adds single quotes around
       
  1615 ** the outside of the total string.  Additionally, if the parameter in the
       
  1616 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
       
  1617 ** single quotes) in place of the %Q option.  So, for example, one could say:
       
  1618 **
       
  1619 ** <blockquote><pre>
       
  1620 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
       
  1621 **  sqlite3_exec(db, zSQL, 0, 0, 0);
       
  1622 **  sqlite3_free(zSQL);
       
  1623 ** </pre></blockquote>
       
  1624 **
       
  1625 ** The code above will render a correct SQL statement in the zSQL
       
  1626 ** variable even if the zText variable is a NULL pointer.
       
  1627 **
       
  1628 ** The "%z" formatting option works exactly like "%s" with the
       
  1629 ** addition that after the string has been read and copied into
       
  1630 ** the result, [sqlite3_free()] is called on the input string. {END}
       
  1631 **
       
  1632 ** Requirements:
       
  1633 ** [H17403] [H17406] [H17407]
       
  1634 */
       
  1635 char *sqlite3_mprintf(const char*,...);
       
  1636 char *sqlite3_vmprintf(const char*, va_list);
       
  1637 char *sqlite3_snprintf(int,char*,const char*, ...);
       
  1638 
       
  1639 /*
       
  1640 ** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000>
       
  1641 **
       
  1642 ** The SQLite core  uses these three routines for all of its own
       
  1643 ** internal memory allocation needs. "Core" in the previous sentence
       
  1644 ** does not include operating-system specific VFS implementation.  The
       
  1645 ** Windows VFS uses native malloc() and free() for some operations.
       
  1646 **
       
  1647 ** The sqlite3_malloc() routine returns a pointer to a block
       
  1648 ** of memory at least N bytes in length, where N is the parameter.
       
  1649 ** If sqlite3_malloc() is unable to obtain sufficient free
       
  1650 ** memory, it returns a NULL pointer.  If the parameter N to
       
  1651 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
       
  1652 ** a NULL pointer.
       
  1653 **
       
  1654 ** Calling sqlite3_free() with a pointer previously returned
       
  1655 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
       
  1656 ** that it might be reused.  The sqlite3_free() routine is
       
  1657 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
       
  1658 ** to sqlite3_free() is harmless.  After being freed, memory
       
  1659 ** should neither be read nor written.  Even reading previously freed
       
  1660 ** memory might result in a segmentation fault or other severe error.
       
  1661 ** Memory corruption, a segmentation fault, or other severe error
       
  1662 ** might result if sqlite3_free() is called with a non-NULL pointer that
       
  1663 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
       
  1664 **
       
  1665 ** The sqlite3_realloc() interface attempts to resize a
       
  1666 ** prior memory allocation to be at least N bytes, where N is the
       
  1667 ** second parameter.  The memory allocation to be resized is the first
       
  1668 ** parameter.  If the first parameter to sqlite3_realloc()
       
  1669 ** is a NULL pointer then its behavior is identical to calling
       
  1670 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().
       
  1671 ** If the second parameter to sqlite3_realloc() is zero or
       
  1672 ** negative then the behavior is exactly the same as calling
       
  1673 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().
       
  1674 ** sqlite3_realloc() returns a pointer to a memory allocation
       
  1675 ** of at least N bytes in size or NULL if sufficient memory is unavailable.
       
  1676 ** If M is the size of the prior allocation, then min(N,M) bytes
       
  1677 ** of the prior allocation are copied into the beginning of buffer returned
       
  1678 ** by sqlite3_realloc() and the prior allocation is freed.
       
  1679 ** If sqlite3_realloc() returns NULL, then the prior allocation
       
  1680 ** is not freed.
       
  1681 **
       
  1682 ** The memory returned by sqlite3_malloc() and sqlite3_realloc()
       
  1683 ** is always aligned to at least an 8 byte boundary. {END}
       
  1684 **
       
  1685 ** The default implementation of the memory allocation subsystem uses
       
  1686 ** the malloc(), realloc() and free() provided by the standard C library.
       
  1687 ** {H17382} However, if SQLite is compiled with the
       
  1688 ** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i>
       
  1689 ** is an integer), then SQLite create a static array of at least
       
  1690 ** <i>NNN</i> bytes in size and uses that array for all of its dynamic
       
  1691 ** memory allocation needs. {END}  Additional memory allocator options
       
  1692 ** may be added in future releases.
       
  1693 **
       
  1694 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
       
  1695 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
       
  1696 ** implementation of these routines to be omitted.  That capability
       
  1697 ** is no longer provided.  Only built-in memory allocators can be used.
       
  1698 **
       
  1699 ** The Windows OS interface layer calls
       
  1700 ** the system malloc() and free() directly when converting
       
  1701 ** filenames between the UTF-8 encoding used by SQLite
       
  1702 ** and whatever filename encoding is used by the particular Windows
       
  1703 ** installation.  Memory allocation errors are detected, but
       
  1704 ** they are reported back as [SQLITE_CANTOPEN] or
       
  1705 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
       
  1706 **
       
  1707 ** Requirements:
       
  1708 ** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318]
       
  1709 ** [H17321] [H17322] [H17323]
       
  1710 **
       
  1711 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
       
  1712 ** must be either NULL or else pointers obtained from a prior
       
  1713 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
       
  1714 ** not yet been released.
       
  1715 **
       
  1716 ** The application must not read or write any part of
       
  1717 ** a block of memory after it has been released using
       
  1718 ** [sqlite3_free()] or [sqlite3_realloc()].
       
  1719 */
       
  1720 void *sqlite3_malloc(int);
       
  1721 void *sqlite3_realloc(void*, int);
       
  1722 void sqlite3_free(void*);
       
  1723 
       
  1724 /*
       
  1725 ** CAPI3REF: Memory Allocator Statistics {H17370} <S30210>
       
  1726 **
       
  1727 ** SQLite provides these two interfaces for reporting on the status
       
  1728 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
       
  1729 ** routines, which form the built-in memory allocation subsystem.
       
  1730 **
       
  1731 ** Requirements:
       
  1732 ** [H17371] [H17373] [H17374] [H17375]
       
  1733 */
       
  1734 sqlite3_int64 sqlite3_memory_used(void);
       
  1735 sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
       
  1736 
       
  1737 /*
       
  1738 ** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000>
       
  1739 **
       
  1740 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
       
  1741 ** select random [ROWID | ROWIDs] when inserting new records into a table that
       
  1742 ** already uses the largest possible [ROWID].  The PRNG is also used for
       
  1743 ** the build-in random() and randomblob() SQL functions.  This interface allows
       
  1744 ** applications to access the same PRNG for other purposes.
       
  1745 **
       
  1746 ** A call to this routine stores N bytes of randomness into buffer P.
       
  1747 **
       
  1748 ** The first time this routine is invoked (either internally or by
       
  1749 ** the application) the PRNG is seeded using randomness obtained
       
  1750 ** from the xRandomness method of the default [sqlite3_vfs] object.
       
  1751 ** On all subsequent invocations, the pseudo-randomness is generated
       
  1752 ** internally and without recourse to the [sqlite3_vfs] xRandomness
       
  1753 ** method.
       
  1754 **
       
  1755 ** Requirements:
       
  1756 ** [H17392]
       
  1757 */
       
  1758 void sqlite3_randomness(int N, void *P);
       
  1759 
       
  1760 /*
       
  1761 ** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100>
       
  1762 **
       
  1763 ** This routine registers a authorizer callback with a particular
       
  1764 ** [database connection], supplied in the first argument.
       
  1765 ** The authorizer callback is invoked as SQL statements are being compiled
       
  1766 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
       
  1767 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  At various
       
  1768 ** points during the compilation process, as logic is being created
       
  1769 ** to perform various actions, the authorizer callback is invoked to
       
  1770 ** see if those actions are allowed.  The authorizer callback should
       
  1771 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
       
  1772 ** specific action but allow the SQL statement to continue to be
       
  1773 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
       
  1774 ** rejected with an error.  If the authorizer callback returns
       
  1775 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
       
  1776 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
       
  1777 ** the authorizer will fail with an error message.
       
  1778 **
       
  1779 ** When the callback returns [SQLITE_OK], that means the operation
       
  1780 ** requested is ok.  When the callback returns [SQLITE_DENY], the
       
  1781 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
       
  1782 ** authorizer will fail with an error message explaining that
       
  1783 ** access is denied.  If the authorizer code is [SQLITE_READ]
       
  1784 ** and the callback returns [SQLITE_IGNORE] then the
       
  1785 ** [prepared statement] statement is constructed to substitute
       
  1786 ** a NULL value in place of the table column that would have
       
  1787 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
       
  1788 ** return can be used to deny an untrusted user access to individual
       
  1789 ** columns of a table.
       
  1790 **
       
  1791 ** The first parameter to the authorizer callback is a copy of the third
       
  1792 ** parameter to the sqlite3_set_authorizer() interface. The second parameter
       
  1793 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
       
  1794 ** the particular action to be authorized. The third through sixth parameters
       
  1795 ** to the callback are zero-terminated strings that contain additional
       
  1796 ** details about the action to be authorized.
       
  1797 **
       
  1798 ** An authorizer is used when [sqlite3_prepare | preparing]
       
  1799 ** SQL statements from an untrusted source, to ensure that the SQL statements
       
  1800 ** do not try to access data they are not allowed to see, or that they do not
       
  1801 ** try to execute malicious statements that damage the database.  For
       
  1802 ** example, an application may allow a user to enter arbitrary
       
  1803 ** SQL queries for evaluation by a database.  But the application does
       
  1804 ** not want the user to be able to make arbitrary changes to the
       
  1805 ** database.  An authorizer could then be put in place while the
       
  1806 ** user-entered SQL is being [sqlite3_prepare | prepared] that
       
  1807 ** disallows everything except [SELECT] statements.
       
  1808 **
       
  1809 ** Applications that need to process SQL from untrusted sources
       
  1810 ** might also consider lowering resource limits using [sqlite3_limit()]
       
  1811 ** and limiting database size using the [max_page_count] [PRAGMA]
       
  1812 ** in addition to using an authorizer.
       
  1813 **
       
  1814 ** Only a single authorizer can be in place on a database connection
       
  1815 ** at a time.  Each call to sqlite3_set_authorizer overrides the
       
  1816 ** previous call.  Disable the authorizer by installing a NULL callback.
       
  1817 ** The authorizer is disabled by default.
       
  1818 **
       
  1819 ** The authorizer callback must not do anything that will modify
       
  1820 ** the database connection that invoked the authorizer callback.
       
  1821 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  1822 ** database connections for the meaning of "modify" in this paragraph.
       
  1823 **
       
  1824 ** When [sqlite3_prepare_v2()] is used to prepare a statement, the
       
  1825 ** statement might be reprepared during [sqlite3_step()] due to a 
       
  1826 ** schema change.  Hence, the application should ensure that the
       
  1827 ** correct authorizer callback remains in place during the [sqlite3_step()].
       
  1828 **
       
  1829 ** Note that the authorizer callback is invoked only during
       
  1830 ** [sqlite3_prepare()] or its variants.  Authorization is not
       
  1831 ** performed during statement evaluation in [sqlite3_step()].
       
  1832 **
       
  1833 ** Requirements:
       
  1834 ** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510]
       
  1835 ** [H12511] [H12512] [H12520] [H12521] [H12522]
       
  1836 */
       
  1837 int sqlite3_set_authorizer(
       
  1838   sqlite3*,
       
  1839   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
       
  1840   void *pUserData
       
  1841 );
       
  1842 
       
  1843 /*
       
  1844 ** CAPI3REF: Authorizer Return Codes {H12590} <H12500>
       
  1845 **
       
  1846 ** The [sqlite3_set_authorizer | authorizer callback function] must
       
  1847 ** return either [SQLITE_OK] or one of these two constants in order
       
  1848 ** to signal SQLite whether or not the action is permitted.  See the
       
  1849 ** [sqlite3_set_authorizer | authorizer documentation] for additional
       
  1850 ** information.
       
  1851 */
       
  1852 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
       
  1853 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
       
  1854 
       
  1855 /*
       
  1856 ** CAPI3REF: Authorizer Action Codes {H12550} <H12500>
       
  1857 **
       
  1858 ** The [sqlite3_set_authorizer()] interface registers a callback function
       
  1859 ** that is invoked to authorize certain SQL statement actions.  The
       
  1860 ** second parameter to the callback is an integer code that specifies
       
  1861 ** what action is being authorized.  These are the integer action codes that
       
  1862 ** the authorizer callback may be passed.
       
  1863 **
       
  1864 ** These action code values signify what kind of operation is to be
       
  1865 ** authorized.  The 3rd and 4th parameters to the authorization
       
  1866 ** callback function will be parameters or NULL depending on which of these
       
  1867 ** codes is used as the second parameter.  The 5th parameter to the
       
  1868 ** authorizer callback is the name of the database ("main", "temp",
       
  1869 ** etc.) if applicable.  The 6th parameter to the authorizer callback
       
  1870 ** is the name of the inner-most trigger or view that is responsible for
       
  1871 ** the access attempt or NULL if this access attempt is directly from
       
  1872 ** top-level SQL code.
       
  1873 **
       
  1874 ** Requirements:
       
  1875 ** [H12551] [H12552] [H12553] [H12554]
       
  1876 */
       
  1877 /******************************************* 3rd ************ 4th ***********/
       
  1878 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
       
  1879 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
       
  1880 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
       
  1881 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
       
  1882 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
       
  1883 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
       
  1884 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
       
  1885 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
       
  1886 #define SQLITE_DELETE                9   /* Table Name      NULL            */
       
  1887 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
       
  1888 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
       
  1889 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
       
  1890 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
       
  1891 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
       
  1892 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
       
  1893 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
       
  1894 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
       
  1895 #define SQLITE_INSERT               18   /* Table Name      NULL            */
       
  1896 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
       
  1897 #define SQLITE_READ                 20   /* Table Name      Column Name     */
       
  1898 #define SQLITE_SELECT               21   /* NULL            NULL            */
       
  1899 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
       
  1900 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
       
  1901 #define SQLITE_ATTACH               24   /* Filename        NULL            */
       
  1902 #define SQLITE_DETACH               25   /* Database Name   NULL            */
       
  1903 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
       
  1904 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
       
  1905 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
       
  1906 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
       
  1907 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
       
  1908 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
       
  1909 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
       
  1910 #define SQLITE_COPY                  0   /* No longer used */
       
  1911 
       
  1912 /*
       
  1913 ** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400>
       
  1914 ** EXPERIMENTAL
       
  1915 **
       
  1916 ** These routines register callback functions that can be used for
       
  1917 ** tracing and profiling the execution of SQL statements.
       
  1918 **
       
  1919 ** The callback function registered by sqlite3_trace() is invoked at
       
  1920 ** various times when an SQL statement is being run by [sqlite3_step()].
       
  1921 ** The callback returns a UTF-8 rendering of the SQL statement text
       
  1922 ** as the statement first begins executing.  Additional callbacks occur
       
  1923 ** as each triggered subprogram is entered.  The callbacks for triggers
       
  1924 ** contain a UTF-8 SQL comment that identifies the trigger.
       
  1925 **
       
  1926 ** The callback function registered by sqlite3_profile() is invoked
       
  1927 ** as each SQL statement finishes.  The profile callback contains
       
  1928 ** the original statement text and an estimate of wall-clock time
       
  1929 ** of how long that statement took to run.
       
  1930 **
       
  1931 ** Requirements:
       
  1932 ** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289]
       
  1933 ** [H12290]
       
  1934 */
       
  1935 SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
       
  1936 SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,
       
  1937    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
       
  1938 
       
  1939 /*
       
  1940 ** CAPI3REF: Query Progress Callbacks {H12910} <S60400>
       
  1941 **
       
  1942 ** This routine configures a callback function - the
       
  1943 ** progress callback - that is invoked periodically during long
       
  1944 ** running calls to [sqlite3_exec()], [sqlite3_step()] and
       
  1945 ** [sqlite3_get_table()].  An example use for this
       
  1946 ** interface is to keep a GUI updated during a large query.
       
  1947 **
       
  1948 ** If the progress callback returns non-zero, the operation is
       
  1949 ** interrupted.  This feature can be used to implement a
       
  1950 ** "Cancel" button on a GUI progress dialog box.
       
  1951 **
       
  1952 ** The progress handler must not do anything that will modify
       
  1953 ** the database connection that invoked the progress handler.
       
  1954 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  1955 ** database connections for the meaning of "modify" in this paragraph.
       
  1956 **
       
  1957 ** Requirements:
       
  1958 ** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918]
       
  1959 **
       
  1960 */
       
  1961 void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
       
  1962 
       
  1963 /*
       
  1964 ** CAPI3REF: Opening A New Database Connection {H12700} <S40200>
       
  1965 **
       
  1966 ** These routines open an SQLite database file whose name is given by the
       
  1967 ** filename argument. The filename argument is interpreted as UTF-8 for
       
  1968 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
       
  1969 ** order for sqlite3_open16(). A [database connection] handle is usually
       
  1970 ** returned in *ppDb, even if an error occurs.  The only exception is that
       
  1971 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
       
  1972 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
       
  1973 ** object. If the database is opened (and/or created) successfully, then
       
  1974 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.  The
       
  1975 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
       
  1976 ** an English language description of the error.
       
  1977 **
       
  1978 ** The default encoding for the database will be UTF-8 if
       
  1979 ** sqlite3_open() or sqlite3_open_v2() is called and
       
  1980 ** UTF-16 in the native byte order if sqlite3_open16() is used.
       
  1981 **
       
  1982 ** Whether or not an error occurs when it is opened, resources
       
  1983 ** associated with the [database connection] handle should be released by
       
  1984 ** passing it to [sqlite3_close()] when it is no longer required.
       
  1985 **
       
  1986 ** The sqlite3_open_v2() interface works like sqlite3_open()
       
  1987 ** except that it accepts two additional parameters for additional control
       
  1988 ** over the new database connection.  The flags parameter can take one of
       
  1989 ** the following three values, optionally combined with the 
       
  1990 ** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags:
       
  1991 **
       
  1992 ** <dl>
       
  1993 ** <dt>[SQLITE_OPEN_READONLY]</dt>
       
  1994 ** <dd>The database is opened in read-only mode.  If the database does not
       
  1995 ** already exist, an error is returned.</dd>
       
  1996 **
       
  1997 ** <dt>[SQLITE_OPEN_READWRITE]</dt>
       
  1998 ** <dd>The database is opened for reading and writing if possible, or reading
       
  1999 ** only if the file is write protected by the operating system.  In either
       
  2000 ** case the database must already exist, otherwise an error is returned.</dd>
       
  2001 **
       
  2002 ** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
       
  2003 ** <dd>The database is opened for reading and writing, and is creates it if
       
  2004 ** it does not already exist. This is the behavior that is always used for
       
  2005 ** sqlite3_open() and sqlite3_open16().</dd>
       
  2006 ** </dl>
       
  2007 **
       
  2008 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
       
  2009 ** combinations shown above or one of the combinations shown above combined
       
  2010 ** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags,
       
  2011 ** then the behavior is undefined.
       
  2012 **
       
  2013 ** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
       
  2014 ** opens in the multi-thread [threading mode] as long as the single-thread
       
  2015 ** mode has not been set at compile-time or start-time.  If the
       
  2016 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
       
  2017 ** in the serialized [threading mode] unless single-thread was
       
  2018 ** previously selected at compile-time or start-time.
       
  2019 **
       
  2020 ** If the filename is ":memory:", then a private, temporary in-memory database
       
  2021 ** is created for the connection.  This in-memory database will vanish when
       
  2022 ** the database connection is closed.  Future versions of SQLite might
       
  2023 ** make use of additional special filenames that begin with the ":" character.
       
  2024 ** It is recommended that when a database filename actually does begin with
       
  2025 ** a ":" character you should prefix the filename with a pathname such as
       
  2026 ** "./" to avoid ambiguity.
       
  2027 **
       
  2028 ** If the filename is an empty string, then a private, temporary
       
  2029 ** on-disk database will be created.  This private database will be
       
  2030 ** automatically deleted as soon as the database connection is closed.
       
  2031 **
       
  2032 ** The fourth parameter to sqlite3_open_v2() is the name of the
       
  2033 ** [sqlite3_vfs] object that defines the operating system interface that
       
  2034 ** the new database connection should use.  If the fourth parameter is
       
  2035 ** a NULL pointer then the default [sqlite3_vfs] object is used.
       
  2036 **
       
  2037 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
       
  2038 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
       
  2039 ** codepage is currently defined.  Filenames containing international
       
  2040 ** characters must be converted to UTF-8 prior to passing them into
       
  2041 ** sqlite3_open() or sqlite3_open_v2().
       
  2042 **
       
  2043 ** Requirements:
       
  2044 ** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711]
       
  2045 ** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723]
       
  2046 */
       
  2047 int sqlite3_open(
       
  2048   const char *filename,   /* Database filename (UTF-8) */
       
  2049   sqlite3 **ppDb          /* OUT: SQLite db handle */
       
  2050 );
       
  2051 int sqlite3_open16(
       
  2052   const void *filename,   /* Database filename (UTF-16) */
       
  2053   sqlite3 **ppDb          /* OUT: SQLite db handle */
       
  2054 );
       
  2055 int sqlite3_open_v2(
       
  2056   const char *filename,   /* Database filename (UTF-8) */
       
  2057   sqlite3 **ppDb,         /* OUT: SQLite db handle */
       
  2058   int flags,              /* Flags */
       
  2059   const char *zVfs        /* Name of VFS module to use */
       
  2060 );
       
  2061 
       
  2062 /*
       
  2063 ** CAPI3REF: Error Codes And Messages {H12800} <S60200>
       
  2064 **
       
  2065 ** The sqlite3_errcode() interface returns the numeric [result code] or
       
  2066 ** [extended result code] for the most recent failed sqlite3_* API call
       
  2067 ** associated with a [database connection]. If a prior API call failed
       
  2068 ** but the most recent API call succeeded, the return value from
       
  2069 ** sqlite3_errcode() is undefined.  The sqlite3_extended_errcode()
       
  2070 ** interface is the same except that it always returns the 
       
  2071 ** [extended result code] even when extended result codes are
       
  2072 ** disabled.
       
  2073 **
       
  2074 ** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
       
  2075 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
       
  2076 ** Memory to hold the error message string is managed internally.
       
  2077 ** The application does not need to worry about freeing the result.
       
  2078 ** However, the error string might be overwritten or deallocated by
       
  2079 ** subsequent calls to other SQLite interface functions.
       
  2080 **
       
  2081 ** When the serialized [threading mode] is in use, it might be the
       
  2082 ** case that a second error occurs on a separate thread in between
       
  2083 ** the time of the first error and the call to these interfaces.
       
  2084 ** When that happens, the second error will be reported since these
       
  2085 ** interfaces always report the most recent result.  To avoid
       
  2086 ** this, each thread can obtain exclusive use of the [database connection] D
       
  2087 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
       
  2088 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
       
  2089 ** all calls to the interfaces listed here are completed.
       
  2090 **
       
  2091 ** If an interface fails with SQLITE_MISUSE, that means the interface
       
  2092 ** was invoked incorrectly by the application.  In that case, the
       
  2093 ** error code and message may or may not be set.
       
  2094 **
       
  2095 ** Requirements:
       
  2096 ** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809]
       
  2097 */
       
  2098 int sqlite3_errcode(sqlite3 *db);
       
  2099 int sqlite3_extended_errcode(sqlite3 *db);
       
  2100 const char *sqlite3_errmsg(sqlite3*);
       
  2101 const void *sqlite3_errmsg16(sqlite3*);
       
  2102 
       
  2103 /*
       
  2104 ** CAPI3REF: SQL Statement Object {H13000} <H13010>
       
  2105 ** KEYWORDS: {prepared statement} {prepared statements}
       
  2106 **
       
  2107 ** An instance of this object represents a single SQL statement.
       
  2108 ** This object is variously known as a "prepared statement" or a
       
  2109 ** "compiled SQL statement" or simply as a "statement".
       
  2110 **
       
  2111 ** The life of a statement object goes something like this:
       
  2112 **
       
  2113 ** <ol>
       
  2114 ** <li> Create the object using [sqlite3_prepare_v2()] or a related
       
  2115 **      function.
       
  2116 ** <li> Bind values to [host parameters] using the sqlite3_bind_*()
       
  2117 **      interfaces.
       
  2118 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
       
  2119 ** <li> Reset the statement using [sqlite3_reset()] then go back
       
  2120 **      to step 2.  Do this zero or more times.
       
  2121 ** <li> Destroy the object using [sqlite3_finalize()].
       
  2122 ** </ol>
       
  2123 **
       
  2124 ** Refer to documentation on individual methods above for additional
       
  2125 ** information.
       
  2126 */
       
  2127 typedef struct sqlite3_stmt sqlite3_stmt;
       
  2128 
       
  2129 /*
       
  2130 ** CAPI3REF: Run-time Limits {H12760} <S20600>
       
  2131 **
       
  2132 ** This interface allows the size of various constructs to be limited
       
  2133 ** on a connection by connection basis.  The first parameter is the
       
  2134 ** [database connection] whose limit is to be set or queried.  The
       
  2135 ** second parameter is one of the [limit categories] that define a
       
  2136 ** class of constructs to be size limited.  The third parameter is the
       
  2137 ** new limit for that construct.  The function returns the old limit.
       
  2138 **
       
  2139 ** If the new limit is a negative number, the limit is unchanged.
       
  2140 ** For the limit category of SQLITE_LIMIT_XYZ there is a 
       
  2141 ** [limits | hard upper bound]
       
  2142 ** set by a compile-time C preprocessor macro named 
       
  2143 ** [limits | SQLITE_MAX_XYZ].
       
  2144 ** (The "_LIMIT_" in the name is changed to "_MAX_".)
       
  2145 ** Attempts to increase a limit above its hard upper bound are
       
  2146 ** silently truncated to the hard upper limit.
       
  2147 **
       
  2148 ** Run time limits are intended for use in applications that manage
       
  2149 ** both their own internal database and also databases that are controlled
       
  2150 ** by untrusted external sources.  An example application might be a
       
  2151 ** web browser that has its own databases for storing history and
       
  2152 ** separate databases controlled by JavaScript applications downloaded
       
  2153 ** off the Internet.  The internal databases can be given the
       
  2154 ** large, default limits.  Databases managed by external sources can
       
  2155 ** be given much smaller limits designed to prevent a denial of service
       
  2156 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
       
  2157 ** interface to further control untrusted SQL.  The size of the database
       
  2158 ** created by an untrusted script can be contained using the
       
  2159 ** [max_page_count] [PRAGMA].
       
  2160 **
       
  2161 ** New run-time limit categories may be added in future releases.
       
  2162 **
       
  2163 ** Requirements:
       
  2164 ** [H12762] [H12766] [H12769]
       
  2165 */
       
  2166 int sqlite3_limit(sqlite3*, int id, int newVal);
       
  2167 
       
  2168 /*
       
  2169 ** CAPI3REF: Run-Time Limit Categories {H12790} <H12760>
       
  2170 ** KEYWORDS: {limit category} {limit categories}
       
  2171 **
       
  2172 ** These constants define various performance limits
       
  2173 ** that can be lowered at run-time using [sqlite3_limit()].
       
  2174 ** The synopsis of the meanings of the various limits is shown below.
       
  2175 ** Additional information is available at [limits | Limits in SQLite].
       
  2176 **
       
  2177 ** <dl>
       
  2178 ** <dt>SQLITE_LIMIT_LENGTH</dt>
       
  2179 ** <dd>The maximum size of any string or BLOB or table row.<dd>
       
  2180 **
       
  2181 ** <dt>SQLITE_LIMIT_SQL_LENGTH</dt>
       
  2182 ** <dd>The maximum length of an SQL statement.</dd>
       
  2183 **
       
  2184 ** <dt>SQLITE_LIMIT_COLUMN</dt>
       
  2185 ** <dd>The maximum number of columns in a table definition or in the
       
  2186 ** result set of a [SELECT] or the maximum number of columns in an index
       
  2187 ** or in an ORDER BY or GROUP BY clause.</dd>
       
  2188 **
       
  2189 ** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
       
  2190 ** <dd>The maximum depth of the parse tree on any expression.</dd>
       
  2191 **
       
  2192 ** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
       
  2193 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>
       
  2194 **
       
  2195 ** <dt>SQLITE_LIMIT_VDBE_OP</dt>
       
  2196 ** <dd>The maximum number of instructions in a virtual machine program
       
  2197 ** used to implement an SQL statement.</dd>
       
  2198 **
       
  2199 ** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
       
  2200 ** <dd>The maximum number of arguments on a function.</dd>
       
  2201 **
       
  2202 ** <dt>SQLITE_LIMIT_ATTACHED</dt>
       
  2203 ** <dd>The maximum number of [ATTACH | attached databases].</dd>
       
  2204 **
       
  2205 ** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
       
  2206 ** <dd>The maximum length of the pattern argument to the [LIKE] or
       
  2207 ** [GLOB] operators.</dd>
       
  2208 **
       
  2209 ** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
       
  2210 ** <dd>The maximum number of variables in an SQL statement that can
       
  2211 ** be bound.</dd>
       
  2212 ** </dl>
       
  2213 */
       
  2214 #define SQLITE_LIMIT_LENGTH                    0
       
  2215 #define SQLITE_LIMIT_SQL_LENGTH                1
       
  2216 #define SQLITE_LIMIT_COLUMN                    2
       
  2217 #define SQLITE_LIMIT_EXPR_DEPTH                3
       
  2218 #define SQLITE_LIMIT_COMPOUND_SELECT           4
       
  2219 #define SQLITE_LIMIT_VDBE_OP                   5
       
  2220 #define SQLITE_LIMIT_FUNCTION_ARG              6
       
  2221 #define SQLITE_LIMIT_ATTACHED                  7
       
  2222 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
       
  2223 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
       
  2224 
       
  2225 /*
       
  2226 ** CAPI3REF: Compiling An SQL Statement {H13010} <S10000>
       
  2227 ** KEYWORDS: {SQL statement compiler}
       
  2228 **
       
  2229 ** To execute an SQL query, it must first be compiled into a byte-code
       
  2230 ** program using one of these routines.
       
  2231 **
       
  2232 ** The first argument, "db", is a [database connection] obtained from a
       
  2233 ** prior call to [sqlite3_open()], [sqlite3_open_v2()] or [sqlite3_open16()].
       
  2234 **
       
  2235 ** The second argument, "zSql", is the statement to be compiled, encoded
       
  2236 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
       
  2237 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
       
  2238 ** use UTF-16.
       
  2239 **
       
  2240 ** If the nByte argument is less than zero, then zSql is read up to the
       
  2241 ** first zero terminator. If nByte is non-negative, then it is the maximum
       
  2242 ** number of  bytes read from zSql.  When nByte is non-negative, the
       
  2243 ** zSql string ends at either the first '\000' or '\u0000' character or
       
  2244 ** the nByte-th byte, whichever comes first. If the caller knows
       
  2245 ** that the supplied string is nul-terminated, then there is a small
       
  2246 ** performance advantage to be gained by passing an nByte parameter that
       
  2247 ** is equal to the number of bytes in the input string <i>including</i>
       
  2248 ** the nul-terminator bytes.
       
  2249 **
       
  2250 ** *pzTail is made to point to the first byte past the end of the
       
  2251 ** first SQL statement in zSql.  These routines only compile the first
       
  2252 ** statement in zSql, so *pzTail is left pointing to what remains
       
  2253 ** uncompiled.
       
  2254 **
       
  2255 ** *ppStmt is left pointing to a compiled [prepared statement] that can be
       
  2256 ** executed using [sqlite3_step()].  If there is an error, *ppStmt is set
       
  2257 ** to NULL.  If the input text contains no SQL (if the input is an empty
       
  2258 ** string or a comment) then *ppStmt is set to NULL.
       
  2259 ** {A13018} The calling procedure is responsible for deleting the compiled
       
  2260 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
       
  2261 **
       
  2262 ** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned.
       
  2263 **
       
  2264 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
       
  2265 ** recommended for all new programs. The two older interfaces are retained
       
  2266 ** for backwards compatibility, but their use is discouraged.
       
  2267 ** In the "v2" interfaces, the prepared statement
       
  2268 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
       
  2269 ** original SQL text. This causes the [sqlite3_step()] interface to
       
  2270 ** behave a differently in two ways:
       
  2271 **
       
  2272 ** <ol>
       
  2273 ** <li>
       
  2274 ** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
       
  2275 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
       
  2276 ** statement and try to run it again.  If the schema has changed in
       
  2277 ** a way that makes the statement no longer valid, [sqlite3_step()] will still
       
  2278 ** return [SQLITE_SCHEMA].  But unlike the legacy behavior, [SQLITE_SCHEMA] is
       
  2279 ** now a fatal error.  Calling [sqlite3_prepare_v2()] again will not make the
       
  2280 ** error go away.  Note: use [sqlite3_errmsg()] to find the text
       
  2281 ** of the parsing error that results in an [SQLITE_SCHEMA] return.
       
  2282 ** </li>
       
  2283 **
       
  2284 ** <li>
       
  2285 ** When an error occurs, [sqlite3_step()] will return one of the detailed
       
  2286 ** [error codes] or [extended error codes].  The legacy behavior was that
       
  2287 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
       
  2288 ** and you would have to make a second call to [sqlite3_reset()] in order
       
  2289 ** to find the underlying cause of the problem. With the "v2" prepare
       
  2290 ** interfaces, the underlying reason for the error is returned immediately.
       
  2291 ** </li>
       
  2292 ** </ol>
       
  2293 **
       
  2294 ** Requirements:
       
  2295 ** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021]
       
  2296 **
       
  2297 */
       
  2298 int sqlite3_prepare(
       
  2299   sqlite3 *db,            /* Database handle */
       
  2300   const char *zSql,       /* SQL statement, UTF-8 encoded */
       
  2301   int nByte,              /* Maximum length of zSql in bytes. */
       
  2302   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2303   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2304 );
       
  2305 int sqlite3_prepare_v2(
       
  2306   sqlite3 *db,            /* Database handle */
       
  2307   const char *zSql,       /* SQL statement, UTF-8 encoded */
       
  2308   int nByte,              /* Maximum length of zSql in bytes. */
       
  2309   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2310   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2311 );
       
  2312 int sqlite3_prepare16(
       
  2313   sqlite3 *db,            /* Database handle */
       
  2314   const void *zSql,       /* SQL statement, UTF-16 encoded */
       
  2315   int nByte,              /* Maximum length of zSql in bytes. */
       
  2316   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2317   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2318 );
       
  2319 int sqlite3_prepare16_v2(
       
  2320   sqlite3 *db,            /* Database handle */
       
  2321   const void *zSql,       /* SQL statement, UTF-16 encoded */
       
  2322   int nByte,              /* Maximum length of zSql in bytes. */
       
  2323   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
       
  2324   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
       
  2325 );
       
  2326 
       
  2327 /*
       
  2328 ** CAPI3REF: Retrieving Statement SQL {H13100} <H13000>
       
  2329 **
       
  2330 ** This interface can be used to retrieve a saved copy of the original
       
  2331 ** SQL text used to create a [prepared statement] if that statement was
       
  2332 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
       
  2333 **
       
  2334 ** Requirements:
       
  2335 ** [H13101] [H13102] [H13103]
       
  2336 */
       
  2337 const char *sqlite3_sql(sqlite3_stmt *pStmt);
       
  2338 
       
  2339 /*
       
  2340 ** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200>
       
  2341 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
       
  2342 **
       
  2343 ** SQLite uses the sqlite3_value object to represent all values
       
  2344 ** that can be stored in a database table. SQLite uses dynamic typing
       
  2345 ** for the values it stores. Values stored in sqlite3_value objects
       
  2346 ** can be integers, floating point values, strings, BLOBs, or NULL.
       
  2347 **
       
  2348 ** An sqlite3_value object may be either "protected" or "unprotected".
       
  2349 ** Some interfaces require a protected sqlite3_value.  Other interfaces
       
  2350 ** will accept either a protected or an unprotected sqlite3_value.
       
  2351 ** Every interface that accepts sqlite3_value arguments specifies
       
  2352 ** whether or not it requires a protected sqlite3_value.
       
  2353 **
       
  2354 ** The terms "protected" and "unprotected" refer to whether or not
       
  2355 ** a mutex is held.  A internal mutex is held for a protected
       
  2356 ** sqlite3_value object but no mutex is held for an unprotected
       
  2357 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
       
  2358 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
       
  2359 ** or if SQLite is run in one of reduced mutex modes 
       
  2360 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
       
  2361 ** then there is no distinction between protected and unprotected
       
  2362 ** sqlite3_value objects and they can be used interchangeably.  However,
       
  2363 ** for maximum code portability it is recommended that applications
       
  2364 ** still make the distinction between between protected and unprotected
       
  2365 ** sqlite3_value objects even when not strictly required.
       
  2366 **
       
  2367 ** The sqlite3_value objects that are passed as parameters into the
       
  2368 ** implementation of [application-defined SQL functions] are protected.
       
  2369 ** The sqlite3_value object returned by
       
  2370 ** [sqlite3_column_value()] is unprotected.
       
  2371 ** Unprotected sqlite3_value objects may only be used with
       
  2372 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
       
  2373 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
       
  2374 ** interfaces require protected sqlite3_value objects.
       
  2375 */
       
  2376 typedef struct Mem sqlite3_value;
       
  2377 
       
  2378 /*
       
  2379 ** CAPI3REF: SQL Function Context Object {H16001} <S20200>
       
  2380 **
       
  2381 ** The context in which an SQL function executes is stored in an
       
  2382 ** sqlite3_context object.  A pointer to an sqlite3_context object
       
  2383 ** is always first parameter to [application-defined SQL functions].
       
  2384 ** The application-defined SQL function implementation will pass this
       
  2385 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
       
  2386 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
       
  2387 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
       
  2388 ** and/or [sqlite3_set_auxdata()].
       
  2389 */
       
  2390 typedef struct sqlite3_context sqlite3_context;
       
  2391 
       
  2392 /*
       
  2393 ** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300>
       
  2394 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
       
  2395 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
       
  2396 **
       
  2397 ** In the SQL strings input to [sqlite3_prepare_v2()] and its variants,
       
  2398 ** literals may be replaced by a [parameter] in one of these forms:
       
  2399 **
       
  2400 ** <ul>
       
  2401 ** <li>  ?
       
  2402 ** <li>  ?NNN
       
  2403 ** <li>  :VVV
       
  2404 ** <li>  @VVV
       
  2405 ** <li>  $VVV
       
  2406 ** </ul>
       
  2407 **
       
  2408 ** In the parameter forms shown above NNN is an integer literal,
       
  2409 ** and VVV is an alpha-numeric parameter name. The values of these
       
  2410 ** parameters (also called "host parameter names" or "SQL parameters")
       
  2411 ** can be set using the sqlite3_bind_*() routines defined here.
       
  2412 **
       
  2413 ** The first argument to the sqlite3_bind_*() routines is always
       
  2414 ** a pointer to the [sqlite3_stmt] object returned from
       
  2415 ** [sqlite3_prepare_v2()] or its variants.
       
  2416 **
       
  2417 ** The second argument is the index of the SQL parameter to be set.
       
  2418 ** The leftmost SQL parameter has an index of 1.  When the same named
       
  2419 ** SQL parameter is used more than once, second and subsequent
       
  2420 ** occurrences have the same index as the first occurrence.
       
  2421 ** The index for named parameters can be looked up using the
       
  2422 ** [sqlite3_bind_parameter_index()] API if desired.  The index
       
  2423 ** for "?NNN" parameters is the value of NNN.
       
  2424 ** The NNN value must be between 1 and the [sqlite3_limit()]
       
  2425 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
       
  2426 **
       
  2427 ** The third argument is the value to bind to the parameter.
       
  2428 **
       
  2429 ** In those routines that have a fourth argument, its value is the
       
  2430 ** number of bytes in the parameter.  To be clear: the value is the
       
  2431 ** number of <u>bytes</u> in the value, not the number of characters.
       
  2432 ** If the fourth parameter is negative, the length of the string is
       
  2433 ** the number of bytes up to the first zero terminator.
       
  2434 **
       
  2435 ** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
       
  2436 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
       
  2437 ** string after SQLite has finished with it. If the fifth argument is
       
  2438 ** the special value [SQLITE_STATIC], then SQLite assumes that the
       
  2439 ** information is in static, unmanaged space and does not need to be freed.
       
  2440 ** If the fifth argument has the value [SQLITE_TRANSIENT], then
       
  2441 ** SQLite makes its own private copy of the data immediately, before
       
  2442 ** the sqlite3_bind_*() routine returns.
       
  2443 **
       
  2444 ** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
       
  2445 ** is filled with zeroes.  A zeroblob uses a fixed amount of memory
       
  2446 ** (just an integer to hold its size) while it is being processed.
       
  2447 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
       
  2448 ** content is later written using
       
  2449 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
       
  2450 ** A negative value for the zeroblob results in a zero-length BLOB.
       
  2451 **
       
  2452 ** The sqlite3_bind_*() routines must be called after
       
  2453 ** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
       
  2454 ** before [sqlite3_step()].
       
  2455 ** Bindings are not cleared by the [sqlite3_reset()] routine.
       
  2456 ** Unbound parameters are interpreted as NULL.
       
  2457 **
       
  2458 ** These routines return [SQLITE_OK] on success or an error code if
       
  2459 ** anything goes wrong.  [SQLITE_RANGE] is returned if the parameter
       
  2460 ** index is out of range.  [SQLITE_NOMEM] is returned if malloc() fails.
       
  2461 ** [SQLITE_MISUSE] might be returned if these routines are called on a
       
  2462 ** virtual machine that is the wrong state or which has already been finalized.
       
  2463 ** Detection of misuse is unreliable.  Applications should not depend
       
  2464 ** on SQLITE_MISUSE returns.  SQLITE_MISUSE is intended to indicate a
       
  2465 ** a logic error in the application.  Future versions of SQLite might
       
  2466 ** panic rather than return SQLITE_MISUSE.
       
  2467 **
       
  2468 ** See also: [sqlite3_bind_parameter_count()],
       
  2469 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
       
  2470 **
       
  2471 ** Requirements:
       
  2472 ** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527]
       
  2473 ** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551]
       
  2474 **
       
  2475 */
       
  2476 int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
       
  2477 int sqlite3_bind_double(sqlite3_stmt*, int, double);
       
  2478 int sqlite3_bind_int(sqlite3_stmt*, int, int);
       
  2479 int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
       
  2480 int sqlite3_bind_null(sqlite3_stmt*, int);
       
  2481 int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
       
  2482 int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
       
  2483 int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
       
  2484 int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
       
  2485 
       
  2486 /*
       
  2487 ** CAPI3REF: Number Of SQL Parameters {H13600} <S70300>
       
  2488 **
       
  2489 ** This routine can be used to find the number of [SQL parameters]
       
  2490 ** in a [prepared statement].  SQL parameters are tokens of the
       
  2491 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
       
  2492 ** placeholders for values that are [sqlite3_bind_blob | bound]
       
  2493 ** to the parameters at a later time.
       
  2494 **
       
  2495 ** This routine actually returns the index of the largest (rightmost)
       
  2496 ** parameter. For all forms except ?NNN, this will correspond to the
       
  2497 ** number of unique parameters.  If parameters of the ?NNN are used,
       
  2498 ** there may be gaps in the list.
       
  2499 **
       
  2500 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  2501 ** [sqlite3_bind_parameter_name()], and
       
  2502 ** [sqlite3_bind_parameter_index()].
       
  2503 **
       
  2504 ** Requirements:
       
  2505 ** [H13601]
       
  2506 */
       
  2507 int sqlite3_bind_parameter_count(sqlite3_stmt*);
       
  2508 
       
  2509 /*
       
  2510 ** CAPI3REF: Name Of A Host Parameter {H13620} <S70300>
       
  2511 **
       
  2512 ** This routine returns a pointer to the name of the n-th
       
  2513 ** [SQL parameter] in a [prepared statement].
       
  2514 ** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
       
  2515 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
       
  2516 ** respectively.
       
  2517 ** In other words, the initial ":" or "$" or "@" or "?"
       
  2518 ** is included as part of the name.
       
  2519 ** Parameters of the form "?" without a following integer have no name
       
  2520 ** and are also referred to as "anonymous parameters".
       
  2521 **
       
  2522 ** The first host parameter has an index of 1, not 0.
       
  2523 **
       
  2524 ** If the value n is out of range or if the n-th parameter is
       
  2525 ** nameless, then NULL is returned.  The returned string is
       
  2526 ** always in UTF-8 encoding even if the named parameter was
       
  2527 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
       
  2528 ** [sqlite3_prepare16_v2()].
       
  2529 **
       
  2530 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  2531 ** [sqlite3_bind_parameter_count()], and
       
  2532 ** [sqlite3_bind_parameter_index()].
       
  2533 **
       
  2534 ** Requirements:
       
  2535 ** [H13621]
       
  2536 */
       
  2537 const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
       
  2538 
       
  2539 /*
       
  2540 ** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300>
       
  2541 **
       
  2542 ** Return the index of an SQL parameter given its name.  The
       
  2543 ** index value returned is suitable for use as the second
       
  2544 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  A zero
       
  2545 ** is returned if no matching parameter is found.  The parameter
       
  2546 ** name must be given in UTF-8 even if the original statement
       
  2547 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
       
  2548 **
       
  2549 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
       
  2550 ** [sqlite3_bind_parameter_count()], and
       
  2551 ** [sqlite3_bind_parameter_index()].
       
  2552 **
       
  2553 ** Requirements:
       
  2554 ** [H13641]
       
  2555 */
       
  2556 int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
       
  2557 
       
  2558 /*
       
  2559 ** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300>
       
  2560 **
       
  2561 ** Contrary to the intuition of many, [sqlite3_reset()] does not reset
       
  2562 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
       
  2563 ** Use this routine to reset all host parameters to NULL.
       
  2564 **
       
  2565 ** Requirements:
       
  2566 ** [H13661]
       
  2567 */
       
  2568 int sqlite3_clear_bindings(sqlite3_stmt*);
       
  2569 
       
  2570 /*
       
  2571 ** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700>
       
  2572 **
       
  2573 ** Return the number of columns in the result set returned by the
       
  2574 ** [prepared statement]. This routine returns 0 if pStmt is an SQL
       
  2575 ** statement that does not return data (for example an [UPDATE]).
       
  2576 **
       
  2577 ** Requirements:
       
  2578 ** [H13711]
       
  2579 */
       
  2580 int sqlite3_column_count(sqlite3_stmt *pStmt);
       
  2581 
       
  2582 /*
       
  2583 ** CAPI3REF: Column Names In A Result Set {H13720} <S10700>
       
  2584 **
       
  2585 ** These routines return the name assigned to a particular column
       
  2586 ** in the result set of a [SELECT] statement.  The sqlite3_column_name()
       
  2587 ** interface returns a pointer to a zero-terminated UTF-8 string
       
  2588 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
       
  2589 ** UTF-16 string.  The first parameter is the [prepared statement]
       
  2590 ** that implements the [SELECT] statement. The second parameter is the
       
  2591 ** column number.  The leftmost column is number 0.
       
  2592 **
       
  2593 ** The returned string pointer is valid until either the [prepared statement]
       
  2594 ** is destroyed by [sqlite3_finalize()] or until the next call to
       
  2595 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
       
  2596 **
       
  2597 ** If sqlite3_malloc() fails during the processing of either routine
       
  2598 ** (for example during a conversion from UTF-8 to UTF-16) then a
       
  2599 ** NULL pointer is returned.
       
  2600 **
       
  2601 ** The name of a result column is the value of the "AS" clause for
       
  2602 ** that column, if there is an AS clause.  If there is no AS clause
       
  2603 ** then the name of the column is unspecified and may change from
       
  2604 ** one release of SQLite to the next.
       
  2605 **
       
  2606 ** Requirements:
       
  2607 ** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727]
       
  2608 */
       
  2609 const char *sqlite3_column_name(sqlite3_stmt*, int N);
       
  2610 const void *sqlite3_column_name16(sqlite3_stmt*, int N);
       
  2611 
       
  2612 /*
       
  2613 ** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700>
       
  2614 **
       
  2615 ** These routines provide a means to determine what column of what
       
  2616 ** table in which database a result of a [SELECT] statement comes from.
       
  2617 ** The name of the database or table or column can be returned as
       
  2618 ** either a UTF-8 or UTF-16 string.  The _database_ routines return
       
  2619 ** the database name, the _table_ routines return the table name, and
       
  2620 ** the origin_ routines return the column name.
       
  2621 ** The returned string is valid until the [prepared statement] is destroyed
       
  2622 ** using [sqlite3_finalize()] or until the same information is requested
       
  2623 ** again in a different encoding.
       
  2624 **
       
  2625 ** The names returned are the original un-aliased names of the
       
  2626 ** database, table, and column.
       
  2627 **
       
  2628 ** The first argument to the following calls is a [prepared statement].
       
  2629 ** These functions return information about the Nth column returned by
       
  2630 ** the statement, where N is the second function argument.
       
  2631 **
       
  2632 ** If the Nth column returned by the statement is an expression or
       
  2633 ** subquery and is not a column value, then all of these functions return
       
  2634 ** NULL.  These routine might also return NULL if a memory allocation error
       
  2635 ** occurs.  Otherwise, they return the name of the attached database, table
       
  2636 ** and column that query result column was extracted from.
       
  2637 **
       
  2638 ** As with all other SQLite APIs, those postfixed with "16" return
       
  2639 ** UTF-16 encoded strings, the other functions return UTF-8. {END}
       
  2640 **
       
  2641 ** These APIs are only available if the library was compiled with the
       
  2642 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
       
  2643 **
       
  2644 ** {A13751}
       
  2645 ** If two or more threads call one or more of these routines against the same
       
  2646 ** prepared statement and column at the same time then the results are
       
  2647 ** undefined.
       
  2648 **
       
  2649 ** Requirements:
       
  2650 ** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748]
       
  2651 **
       
  2652 ** If two or more threads call one or more
       
  2653 ** [sqlite3_column_database_name | column metadata interfaces]
       
  2654 ** for the same [prepared statement] and result column
       
  2655 ** at the same time then the results are undefined.
       
  2656 */
       
  2657 const char *sqlite3_column_database_name(sqlite3_stmt*,int);
       
  2658 const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
       
  2659 const char *sqlite3_column_table_name(sqlite3_stmt*,int);
       
  2660 const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
       
  2661 const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
       
  2662 const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
       
  2663 
       
  2664 /*
       
  2665 ** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700>
       
  2666 **
       
  2667 ** The first parameter is a [prepared statement].
       
  2668 ** If this statement is a [SELECT] statement and the Nth column of the
       
  2669 ** returned result set of that [SELECT] is a table column (not an
       
  2670 ** expression or subquery) then the declared type of the table
       
  2671 ** column is returned.  If the Nth column of the result set is an
       
  2672 ** expression or subquery, then a NULL pointer is returned.
       
  2673 ** The returned string is always UTF-8 encoded. {END}
       
  2674 **
       
  2675 ** For example, given the database schema:
       
  2676 **
       
  2677 ** CREATE TABLE t1(c1 VARIANT);
       
  2678 **
       
  2679 ** and the following statement to be compiled:
       
  2680 **
       
  2681 ** SELECT c1 + 1, c1 FROM t1;
       
  2682 **
       
  2683 ** this routine would return the string "VARIANT" for the second result
       
  2684 ** column (i==1), and a NULL pointer for the first result column (i==0).
       
  2685 **
       
  2686 ** SQLite uses dynamic run-time typing.  So just because a column
       
  2687 ** is declared to contain a particular type does not mean that the
       
  2688 ** data stored in that column is of the declared type.  SQLite is
       
  2689 ** strongly typed, but the typing is dynamic not static.  Type
       
  2690 ** is associated with individual values, not with the containers
       
  2691 ** used to hold those values.
       
  2692 **
       
  2693 ** Requirements:
       
  2694 ** [H13761] [H13762] [H13763]
       
  2695 */
       
  2696 const char *sqlite3_column_decltype(sqlite3_stmt*,int);
       
  2697 const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
       
  2698 
       
  2699 /*
       
  2700 ** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000>
       
  2701 **
       
  2702 ** After a [prepared statement] has been prepared using either
       
  2703 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
       
  2704 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
       
  2705 ** must be called one or more times to evaluate the statement.
       
  2706 **
       
  2707 ** The details of the behavior of the sqlite3_step() interface depend
       
  2708 ** on whether the statement was prepared using the newer "v2" interface
       
  2709 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
       
  2710 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
       
  2711 ** new "v2" interface is recommended for new applications but the legacy
       
  2712 ** interface will continue to be supported.
       
  2713 **
       
  2714 ** In the legacy interface, the return value will be either [SQLITE_BUSY],
       
  2715 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
       
  2716 ** With the "v2" interface, any of the other [result codes] or
       
  2717 ** [extended result codes] might be returned as well.
       
  2718 **
       
  2719 ** [SQLITE_BUSY] means that the database engine was unable to acquire the
       
  2720 ** database locks it needs to do its job.  If the statement is a [COMMIT]
       
  2721 ** or occurs outside of an explicit transaction, then you can retry the
       
  2722 ** statement.  If the statement is not a [COMMIT] and occurs within a
       
  2723 ** explicit transaction then you should rollback the transaction before
       
  2724 ** continuing.
       
  2725 **
       
  2726 ** [SQLITE_DONE] means that the statement has finished executing
       
  2727 ** successfully.  sqlite3_step() should not be called again on this virtual
       
  2728 ** machine without first calling [sqlite3_reset()] to reset the virtual
       
  2729 ** machine back to its initial state.
       
  2730 **
       
  2731 ** If the SQL statement being executed returns any data, then [SQLITE_ROW]
       
  2732 ** is returned each time a new row of data is ready for processing by the
       
  2733 ** caller. The values may be accessed using the [column access functions].
       
  2734 ** sqlite3_step() is called again to retrieve the next row of data.
       
  2735 **
       
  2736 ** [SQLITE_ERROR] means that a run-time error (such as a constraint
       
  2737 ** violation) has occurred.  sqlite3_step() should not be called again on
       
  2738 ** the VM. More information may be found by calling [sqlite3_errmsg()].
       
  2739 ** With the legacy interface, a more specific error code (for example,
       
  2740 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
       
  2741 ** can be obtained by calling [sqlite3_reset()] on the
       
  2742 ** [prepared statement].  In the "v2" interface,
       
  2743 ** the more specific error code is returned directly by sqlite3_step().
       
  2744 **
       
  2745 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
       
  2746 ** Perhaps it was called on a [prepared statement] that has
       
  2747 ** already been [sqlite3_finalize | finalized] or on one that had
       
  2748 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
       
  2749 ** be the case that the same database connection is being used by two or
       
  2750 ** more threads at the same moment in time.
       
  2751 **
       
  2752 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
       
  2753 ** API always returns a generic error code, [SQLITE_ERROR], following any
       
  2754 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
       
  2755 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
       
  2756 ** specific [error codes] that better describes the error.
       
  2757 ** We admit that this is a goofy design.  The problem has been fixed
       
  2758 ** with the "v2" interface.  If you prepare all of your SQL statements
       
  2759 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
       
  2760 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
       
  2761 ** then the more specific [error codes] are returned directly
       
  2762 ** by sqlite3_step().  The use of the "v2" interface is recommended.
       
  2763 **
       
  2764 ** Requirements:
       
  2765 ** [H13202] [H15304] [H15306] [H15308] [H15310]
       
  2766 */
       
  2767 int sqlite3_step(sqlite3_stmt*);
       
  2768 
       
  2769 /*
       
  2770 ** CAPI3REF: Number of columns in a result set {H13770} <S10700>
       
  2771 **
       
  2772 ** Returns the number of values in the current row of the result set.
       
  2773 **
       
  2774 ** Requirements:
       
  2775 ** [H13771] [H13772]
       
  2776 */
       
  2777 int sqlite3_data_count(sqlite3_stmt *pStmt);
       
  2778 
       
  2779 /*
       
  2780 ** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120>
       
  2781 ** KEYWORDS: SQLITE_TEXT
       
  2782 **
       
  2783 ** {H10266} Every value in SQLite has one of five fundamental datatypes:
       
  2784 **
       
  2785 ** <ul>
       
  2786 ** <li> 64-bit signed integer
       
  2787 ** <li> 64-bit IEEE floating point number
       
  2788 ** <li> string
       
  2789 ** <li> BLOB
       
  2790 ** <li> NULL
       
  2791 ** </ul> {END}
       
  2792 **
       
  2793 ** These constants are codes for each of those types.
       
  2794 **
       
  2795 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
       
  2796 ** for a completely different meaning.  Software that links against both
       
  2797 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
       
  2798 ** SQLITE_TEXT.
       
  2799 */
       
  2800 #define SQLITE_INTEGER  1
       
  2801 #define SQLITE_FLOAT    2
       
  2802 #define SQLITE_BLOB     4
       
  2803 #define SQLITE_NULL     5
       
  2804 #ifdef SQLITE_TEXT
       
  2805 # undef SQLITE_TEXT
       
  2806 #else
       
  2807 # define SQLITE_TEXT     3
       
  2808 #endif
       
  2809 #define SQLITE3_TEXT     3
       
  2810 
       
  2811 /*
       
  2812 ** CAPI3REF: Result Values From A Query {H13800} <S10700>
       
  2813 ** KEYWORDS: {column access functions}
       
  2814 **
       
  2815 ** These routines form the "result set query" interface.
       
  2816 **
       
  2817 ** These routines return information about a single column of the current
       
  2818 ** result row of a query.  In every case the first argument is a pointer
       
  2819 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
       
  2820 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
       
  2821 ** and the second argument is the index of the column for which information
       
  2822 ** should be returned.  The leftmost column of the result set has the index 0.
       
  2823 **
       
  2824 ** If the SQL statement does not currently point to a valid row, or if the
       
  2825 ** column index is out of range, the result is undefined.
       
  2826 ** These routines may only be called when the most recent call to
       
  2827 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
       
  2828 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
       
  2829 ** If any of these routines are called after [sqlite3_reset()] or
       
  2830 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
       
  2831 ** something other than [SQLITE_ROW], the results are undefined.
       
  2832 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
       
  2833 ** are called from a different thread while any of these routines
       
  2834 ** are pending, then the results are undefined.
       
  2835 **
       
  2836 ** The sqlite3_column_type() routine returns the
       
  2837 ** [SQLITE_INTEGER | datatype code] for the initial data type
       
  2838 ** of the result column.  The returned value is one of [SQLITE_INTEGER],
       
  2839 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
       
  2840 ** returned by sqlite3_column_type() is only meaningful if no type
       
  2841 ** conversions have occurred as described below.  After a type conversion,
       
  2842 ** the value returned by sqlite3_column_type() is undefined.  Future
       
  2843 ** versions of SQLite may change the behavior of sqlite3_column_type()
       
  2844 ** following a type conversion.
       
  2845 **
       
  2846 ** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
       
  2847 ** routine returns the number of bytes in that BLOB or string.
       
  2848 ** If the result is a UTF-16 string, then sqlite3_column_bytes() converts
       
  2849 ** the string to UTF-8 and then returns the number of bytes.
       
  2850 ** If the result is a numeric value then sqlite3_column_bytes() uses
       
  2851 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
       
  2852 ** the number of bytes in that string.
       
  2853 ** The value returned does not include the zero terminator at the end
       
  2854 ** of the string.  For clarity: the value returned is the number of
       
  2855 ** bytes in the string, not the number of characters.
       
  2856 **
       
  2857 ** Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
       
  2858 ** even empty strings, are always zero terminated.  The return
       
  2859 ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary
       
  2860 ** pointer, possibly even a NULL pointer.
       
  2861 **
       
  2862 ** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes()
       
  2863 ** but leaves the result in UTF-16 in native byte order instead of UTF-8.
       
  2864 ** The zero terminator is not included in this count.
       
  2865 **
       
  2866 ** The object returned by [sqlite3_column_value()] is an
       
  2867 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
       
  2868 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
       
  2869 ** If the [unprotected sqlite3_value] object returned by
       
  2870 ** [sqlite3_column_value()] is used in any other way, including calls
       
  2871 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
       
  2872 ** or [sqlite3_value_bytes()], then the behavior is undefined.
       
  2873 **
       
  2874 ** These routines attempt to convert the value where appropriate.  For
       
  2875 ** example, if the internal representation is FLOAT and a text result
       
  2876 ** is requested, [sqlite3_snprintf()] is used internally to perform the
       
  2877 ** conversion automatically.  The following table details the conversions
       
  2878 ** that are applied:
       
  2879 **
       
  2880 ** <blockquote>
       
  2881 ** <table border="1">
       
  2882 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
       
  2883 **
       
  2884 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
       
  2885 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
       
  2886 ** <tr><td>  NULL    <td>   TEXT    <td> Result is NULL pointer
       
  2887 ** <tr><td>  NULL    <td>   BLOB    <td> Result is NULL pointer
       
  2888 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
       
  2889 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
       
  2890 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
       
  2891 ** <tr><td>  FLOAT   <td> INTEGER   <td> Convert from float to integer
       
  2892 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
       
  2893 ** <tr><td>  FLOAT   <td>   BLOB    <td> Same as FLOAT->TEXT
       
  2894 ** <tr><td>  TEXT    <td> INTEGER   <td> Use atoi()
       
  2895 ** <tr><td>  TEXT    <td>  FLOAT    <td> Use atof()
       
  2896 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
       
  2897 ** <tr><td>  BLOB    <td> INTEGER   <td> Convert to TEXT then use atoi()
       
  2898 ** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
       
  2899 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
       
  2900 ** </table>
       
  2901 ** </blockquote>
       
  2902 **
       
  2903 ** The table above makes reference to standard C library functions atoi()
       
  2904 ** and atof().  SQLite does not really use these functions.  It has its
       
  2905 ** own equivalent internal routines.  The atoi() and atof() names are
       
  2906 ** used in the table for brevity and because they are familiar to most
       
  2907 ** C programmers.
       
  2908 **
       
  2909 ** Note that when type conversions occur, pointers returned by prior
       
  2910 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
       
  2911 ** sqlite3_column_text16() may be invalidated.
       
  2912 ** Type conversions and pointer invalidations might occur
       
  2913 ** in the following cases:
       
  2914 **
       
  2915 ** <ul>
       
  2916 ** <li> The initial content is a BLOB and sqlite3_column_text() or
       
  2917 **      sqlite3_column_text16() is called.  A zero-terminator might
       
  2918 **      need to be added to the string.</li>
       
  2919 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
       
  2920 **      sqlite3_column_text16() is called.  The content must be converted
       
  2921 **      to UTF-16.</li>
       
  2922 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
       
  2923 **      sqlite3_column_text() is called.  The content must be converted
       
  2924 **      to UTF-8.</li>
       
  2925 ** </ul>
       
  2926 **
       
  2927 ** Conversions between UTF-16be and UTF-16le are always done in place and do
       
  2928 ** not invalidate a prior pointer, though of course the content of the buffer
       
  2929 ** that the prior pointer points to will have been modified.  Other kinds
       
  2930 ** of conversion are done in place when it is possible, but sometimes they
       
  2931 ** are not possible and in those cases prior pointers are invalidated.
       
  2932 **
       
  2933 ** The safest and easiest to remember policy is to invoke these routines
       
  2934 ** in one of the following ways:
       
  2935 **
       
  2936 ** <ul>
       
  2937 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
       
  2938 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
       
  2939 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
       
  2940 ** </ul>
       
  2941 **
       
  2942 ** In other words, you should call sqlite3_column_text(),
       
  2943 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
       
  2944 ** into the desired format, then invoke sqlite3_column_bytes() or
       
  2945 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
       
  2946 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
       
  2947 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
       
  2948 ** with calls to sqlite3_column_bytes().
       
  2949 **
       
  2950 ** The pointers returned are valid until a type conversion occurs as
       
  2951 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
       
  2952 ** [sqlite3_finalize()] is called.  The memory space used to hold strings
       
  2953 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
       
  2954 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
       
  2955 ** [sqlite3_free()].
       
  2956 **
       
  2957 ** If a memory allocation error occurs during the evaluation of any
       
  2958 ** of these routines, a default value is returned.  The default value
       
  2959 ** is either the integer 0, the floating point number 0.0, or a NULL
       
  2960 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
       
  2961 ** [SQLITE_NOMEM].
       
  2962 **
       
  2963 ** Requirements:
       
  2964 ** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824]
       
  2965 ** [H13827] [H13830]
       
  2966 */
       
  2967 const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
       
  2968 int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
       
  2969 int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
       
  2970 double sqlite3_column_double(sqlite3_stmt*, int iCol);
       
  2971 int sqlite3_column_int(sqlite3_stmt*, int iCol);
       
  2972 sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
       
  2973 const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
       
  2974 const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
       
  2975 int sqlite3_column_type(sqlite3_stmt*, int iCol);
       
  2976 sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
       
  2977 
       
  2978 /*
       
  2979 ** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100>
       
  2980 **
       
  2981 ** The sqlite3_finalize() function is called to delete a [prepared statement].
       
  2982 ** If the statement was executed successfully or not executed at all, then
       
  2983 ** SQLITE_OK is returned. If execution of the statement failed then an
       
  2984 ** [error code] or [extended error code] is returned.
       
  2985 **
       
  2986 ** This routine can be called at any point during the execution of the
       
  2987 ** [prepared statement].  If the virtual machine has not
       
  2988 ** completed execution when this routine is called, that is like
       
  2989 ** encountering an error or an [sqlite3_interrupt | interrupt].
       
  2990 ** Incomplete updates may be rolled back and transactions canceled,
       
  2991 ** depending on the circumstances, and the
       
  2992 ** [error code] returned will be [SQLITE_ABORT].
       
  2993 **
       
  2994 ** Requirements:
       
  2995 ** [H11302] [H11304]
       
  2996 */
       
  2997 int sqlite3_finalize(sqlite3_stmt *pStmt);
       
  2998 
       
  2999 /*
       
  3000 ** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300>
       
  3001 **
       
  3002 ** The sqlite3_reset() function is called to reset a [prepared statement]
       
  3003 ** object back to its initial state, ready to be re-executed.
       
  3004 ** Any SQL statement variables that had values bound to them using
       
  3005 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
       
  3006 ** Use [sqlite3_clear_bindings()] to reset the bindings.
       
  3007 **
       
  3008 ** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S
       
  3009 **          back to the beginning of its program.
       
  3010 **
       
  3011 ** {H11334} If the most recent call to [sqlite3_step(S)] for the
       
  3012 **          [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
       
  3013 **          or if [sqlite3_step(S)] has never before been called on S,
       
  3014 **          then [sqlite3_reset(S)] returns [SQLITE_OK].
       
  3015 **
       
  3016 ** {H11336} If the most recent call to [sqlite3_step(S)] for the
       
  3017 **          [prepared statement] S indicated an error, then
       
  3018 **          [sqlite3_reset(S)] returns an appropriate [error code].
       
  3019 **
       
  3020 ** {H11338} The [sqlite3_reset(S)] interface does not change the values
       
  3021 **          of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
       
  3022 */
       
  3023 int sqlite3_reset(sqlite3_stmt *pStmt);
       
  3024 
       
  3025 /*
       
  3026 ** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200>
       
  3027 ** KEYWORDS: {function creation routines}
       
  3028 ** KEYWORDS: {application-defined SQL function}
       
  3029 ** KEYWORDS: {application-defined SQL functions}
       
  3030 **
       
  3031 ** These two functions (collectively known as "function creation routines")
       
  3032 ** are used to add SQL functions or aggregates or to redefine the behavior
       
  3033 ** of existing SQL functions or aggregates.  The only difference between the
       
  3034 ** two is that the second parameter, the name of the (scalar) function or
       
  3035 ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16
       
  3036 ** for sqlite3_create_function16().
       
  3037 **
       
  3038 ** The first parameter is the [database connection] to which the SQL
       
  3039 ** function is to be added.  If a single program uses more than one database
       
  3040 ** connection internally, then SQL functions must be added individually to
       
  3041 ** each database connection.
       
  3042 **
       
  3043 ** The second parameter is the name of the SQL function to be created or
       
  3044 ** redefined.  The length of the name is limited to 255 bytes, exclusive of
       
  3045 ** the zero-terminator.  Note that the name length limit is in bytes, not
       
  3046 ** characters.  Any attempt to create a function with a longer name
       
  3047 ** will result in [SQLITE_ERROR] being returned.
       
  3048 **
       
  3049 ** The third parameter (nArg)
       
  3050 ** is the number of arguments that the SQL function or
       
  3051 ** aggregate takes. If this parameter is negative, then the SQL function or
       
  3052 ** aggregate may take any number of arguments.
       
  3053 **
       
  3054 ** The fourth parameter, eTextRep, specifies what
       
  3055 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
       
  3056 ** its parameters.  Any SQL function implementation should be able to work
       
  3057 ** work with UTF-8, UTF-16le, or UTF-16be.  But some implementations may be
       
  3058 ** more efficient with one encoding than another.  It is allowed to
       
  3059 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple
       
  3060 ** times with the same function but with different values of eTextRep.
       
  3061 ** When multiple implementations of the same function are available, SQLite
       
  3062 ** will pick the one that involves the least amount of data conversion.
       
  3063 ** If there is only a single implementation which does not care what text
       
  3064 ** encoding is used, then the fourth argument should be [SQLITE_ANY].
       
  3065 **
       
  3066 ** The fifth parameter is an arbitrary pointer.  The implementation of the
       
  3067 ** function can gain access to this pointer using [sqlite3_user_data()].
       
  3068 **
       
  3069 ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
       
  3070 ** pointers to C-language functions that implement the SQL function or
       
  3071 ** aggregate. A scalar SQL function requires an implementation of the xFunc
       
  3072 ** callback only, NULL pointers should be passed as the xStep and xFinal
       
  3073 ** parameters. An aggregate SQL function requires an implementation of xStep
       
  3074 ** and xFinal and NULL should be passed for xFunc. To delete an existing
       
  3075 ** SQL function or aggregate, pass NULL for all three function callbacks.
       
  3076 **
       
  3077 ** It is permitted to register multiple implementations of the same
       
  3078 ** functions with the same name but with either differing numbers of
       
  3079 ** arguments or differing preferred text encodings.  SQLite will use
       
  3080 ** the implementation most closely matches the way in which the
       
  3081 ** SQL function is used.  A function implementation with a non-negative
       
  3082 ** nArg parameter is a better match than a function implementation with
       
  3083 ** a negative nArg.  A function where the preferred text encoding
       
  3084 ** matches the database encoding is a better
       
  3085 ** match than a function where the encoding is different.  
       
  3086 ** A function where the encoding difference is between UTF16le and UTF16be
       
  3087 ** is a closer match than a function where the encoding difference is
       
  3088 ** between UTF8 and UTF16.
       
  3089 **
       
  3090 ** Built-in functions may be overloaded by new application-defined functions.
       
  3091 ** The first application-defined function with a given name overrides all
       
  3092 ** built-in functions in the same [database connection] with the same name.
       
  3093 ** Subsequent application-defined functions of the same name only override 
       
  3094 ** prior application-defined functions that are an exact match for the
       
  3095 ** number of parameters and preferred encoding.
       
  3096 **
       
  3097 ** An application-defined function is permitted to call other
       
  3098 ** SQLite interfaces.  However, such calls must not
       
  3099 ** close the database connection nor finalize or reset the prepared
       
  3100 ** statement in which the function is running.
       
  3101 **
       
  3102 ** Requirements:
       
  3103 ** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16124] [H16127]
       
  3104 ** [H16130] [H16133] [H16136] [H16139] [H16142]
       
  3105 */
       
  3106 int sqlite3_create_function(
       
  3107   sqlite3 *db,
       
  3108   const char *zFunctionName,
       
  3109   int nArg,
       
  3110   int eTextRep,
       
  3111   void *pApp,
       
  3112   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3113   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3114   void (*xFinal)(sqlite3_context*)
       
  3115 );
       
  3116 int sqlite3_create_function16(
       
  3117   sqlite3 *db,
       
  3118   const void *zFunctionName,
       
  3119   int nArg,
       
  3120   int eTextRep,
       
  3121   void *pApp,
       
  3122   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
       
  3123   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
       
  3124   void (*xFinal)(sqlite3_context*)
       
  3125 );
       
  3126 
       
  3127 /*
       
  3128 ** CAPI3REF: Text Encodings {H10267} <S50200> <H16100>
       
  3129 **
       
  3130 ** These constant define integer codes that represent the various
       
  3131 ** text encodings supported by SQLite.
       
  3132 */
       
  3133 #define SQLITE_UTF8           1
       
  3134 #define SQLITE_UTF16LE        2
       
  3135 #define SQLITE_UTF16BE        3
       
  3136 #define SQLITE_UTF16          4    /* Use native byte order */
       
  3137 #define SQLITE_ANY            5    /* sqlite3_create_function only */
       
  3138 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
       
  3139 
       
  3140 /*
       
  3141 ** CAPI3REF: Deprecated Functions
       
  3142 ** DEPRECATED
       
  3143 **
       
  3144 ** These functions are [deprecated].  In order to maintain
       
  3145 ** backwards compatibility with older code, these functions continue 
       
  3146 ** to be supported.  However, new applications should avoid
       
  3147 ** the use of these functions.  To help encourage people to avoid
       
  3148 ** using these functions, we are not going to tell you what they do.
       
  3149 */
       
  3150 #ifndef SQLITE_OMIT_DEPRECATED
       
  3151 SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
       
  3152 SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
       
  3153 SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
       
  3154 SQLITE_DEPRECATED int sqlite3_global_recover(void);
       
  3155 SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
       
  3156 SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64);
       
  3157 #endif
       
  3158 
       
  3159 /*
       
  3160 ** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200>
       
  3161 **
       
  3162 ** The C-language implementation of SQL functions and aggregates uses
       
  3163 ** this set of interface routines to access the parameter values on
       
  3164 ** the function or aggregate.
       
  3165 **
       
  3166 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
       
  3167 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
       
  3168 ** define callbacks that implement the SQL functions and aggregates.
       
  3169 ** The 4th parameter to these callbacks is an array of pointers to
       
  3170 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
       
  3171 ** each parameter to the SQL function.  These routines are used to
       
  3172 ** extract values from the [sqlite3_value] objects.
       
  3173 **
       
  3174 ** These routines work only with [protected sqlite3_value] objects.
       
  3175 ** Any attempt to use these routines on an [unprotected sqlite3_value]
       
  3176 ** object results in undefined behavior.
       
  3177 **
       
  3178 ** These routines work just like the corresponding [column access functions]
       
  3179 ** except that  these routines take a single [protected sqlite3_value] object
       
  3180 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
       
  3181 **
       
  3182 ** The sqlite3_value_text16() interface extracts a UTF-16 string
       
  3183 ** in the native byte-order of the host machine.  The
       
  3184 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
       
  3185 ** extract UTF-16 strings as big-endian and little-endian respectively.
       
  3186 **
       
  3187 ** The sqlite3_value_numeric_type() interface attempts to apply
       
  3188 ** numeric affinity to the value.  This means that an attempt is
       
  3189 ** made to convert the value to an integer or floating point.  If
       
  3190 ** such a conversion is possible without loss of information (in other
       
  3191 ** words, if the value is a string that looks like a number)
       
  3192 ** then the conversion is performed.  Otherwise no conversion occurs.
       
  3193 ** The [SQLITE_INTEGER | datatype] after conversion is returned.
       
  3194 **
       
  3195 ** Please pay particular attention to the fact that the pointer returned
       
  3196 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
       
  3197 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
       
  3198 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
       
  3199 ** or [sqlite3_value_text16()].
       
  3200 **
       
  3201 ** These routines must be called from the same thread as
       
  3202 ** the SQL function that supplied the [sqlite3_value*] parameters.
       
  3203 **
       
  3204 ** Requirements:
       
  3205 ** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124]
       
  3206 ** [H15127] [H15130] [H15133] [H15136]
       
  3207 */
       
  3208 const void *sqlite3_value_blob(sqlite3_value*);
       
  3209 int sqlite3_value_bytes(sqlite3_value*);
       
  3210 int sqlite3_value_bytes16(sqlite3_value*);
       
  3211 double sqlite3_value_double(sqlite3_value*);
       
  3212 int sqlite3_value_int(sqlite3_value*);
       
  3213 sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
       
  3214 const unsigned char *sqlite3_value_text(sqlite3_value*);
       
  3215 const void *sqlite3_value_text16(sqlite3_value*);
       
  3216 const void *sqlite3_value_text16le(sqlite3_value*);
       
  3217 const void *sqlite3_value_text16be(sqlite3_value*);
       
  3218 int sqlite3_value_type(sqlite3_value*);
       
  3219 int sqlite3_value_numeric_type(sqlite3_value*);
       
  3220 
       
  3221 /*
       
  3222 ** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200>
       
  3223 **
       
  3224 ** The implementation of aggregate SQL functions use this routine to allocate
       
  3225 ** a structure for storing their state.
       
  3226 **
       
  3227 ** The first time the sqlite3_aggregate_context() routine is called for a
       
  3228 ** particular aggregate, SQLite allocates nBytes of memory, zeroes out that
       
  3229 ** memory, and returns a pointer to it. On second and subsequent calls to
       
  3230 ** sqlite3_aggregate_context() for the same aggregate function index,
       
  3231 ** the same buffer is returned. The implementation of the aggregate can use
       
  3232 ** the returned buffer to accumulate data.
       
  3233 **
       
  3234 ** SQLite automatically frees the allocated buffer when the aggregate
       
  3235 ** query concludes.
       
  3236 **
       
  3237 ** The first parameter should be a copy of the
       
  3238 ** [sqlite3_context | SQL function context] that is the first parameter
       
  3239 ** to the callback routine that implements the aggregate function.
       
  3240 **
       
  3241 ** This routine must be called from the same thread in which
       
  3242 ** the aggregate SQL function is running.
       
  3243 **
       
  3244 ** Requirements:
       
  3245 ** [H16211] [H16213] [H16215] [H16217]
       
  3246 */
       
  3247 void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
       
  3248 
       
  3249 /*
       
  3250 ** CAPI3REF: User Data For Functions {H16240} <S20200>
       
  3251 **
       
  3252 ** The sqlite3_user_data() interface returns a copy of
       
  3253 ** the pointer that was the pUserData parameter (the 5th parameter)
       
  3254 ** of the [sqlite3_create_function()]
       
  3255 ** and [sqlite3_create_function16()] routines that originally
       
  3256 ** registered the application defined function. {END}
       
  3257 **
       
  3258 ** This routine must be called from the same thread in which
       
  3259 ** the application-defined function is running.
       
  3260 **
       
  3261 ** Requirements:
       
  3262 ** [H16243]
       
  3263 */
       
  3264 void *sqlite3_user_data(sqlite3_context*);
       
  3265 
       
  3266 /*
       
  3267 ** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200>
       
  3268 **
       
  3269 ** The sqlite3_context_db_handle() interface returns a copy of
       
  3270 ** the pointer to the [database connection] (the 1st parameter)
       
  3271 ** of the [sqlite3_create_function()]
       
  3272 ** and [sqlite3_create_function16()] routines that originally
       
  3273 ** registered the application defined function.
       
  3274 **
       
  3275 ** Requirements:
       
  3276 ** [H16253]
       
  3277 */
       
  3278 sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
       
  3279 
       
  3280 /*
       
  3281 ** CAPI3REF: Function Auxiliary Data {H16270} <S20200>
       
  3282 **
       
  3283 ** The following two functions may be used by scalar SQL functions to
       
  3284 ** associate metadata with argument values. If the same value is passed to
       
  3285 ** multiple invocations of the same SQL function during query execution, under
       
  3286 ** some circumstances the associated metadata may be preserved. This may
       
  3287 ** be used, for example, to add a regular-expression matching scalar
       
  3288 ** function. The compiled version of the regular expression is stored as
       
  3289 ** metadata associated with the SQL value passed as the regular expression
       
  3290 ** pattern.  The compiled regular expression can be reused on multiple
       
  3291 ** invocations of the same function so that the original pattern string
       
  3292 ** does not need to be recompiled on each invocation.
       
  3293 **
       
  3294 ** The sqlite3_get_auxdata() interface returns a pointer to the metadata
       
  3295 ** associated by the sqlite3_set_auxdata() function with the Nth argument
       
  3296 ** value to the application-defined function. If no metadata has been ever
       
  3297 ** been set for the Nth argument of the function, or if the corresponding
       
  3298 ** function parameter has changed since the meta-data was set,
       
  3299 ** then sqlite3_get_auxdata() returns a NULL pointer.
       
  3300 **
       
  3301 ** The sqlite3_set_auxdata() interface saves the metadata
       
  3302 ** pointed to by its 3rd parameter as the metadata for the N-th
       
  3303 ** argument of the application-defined function.  Subsequent
       
  3304 ** calls to sqlite3_get_auxdata() might return this data, if it has
       
  3305 ** not been destroyed.
       
  3306 ** If it is not NULL, SQLite will invoke the destructor
       
  3307 ** function given by the 4th parameter to sqlite3_set_auxdata() on
       
  3308 ** the metadata when the corresponding function parameter changes
       
  3309 ** or when the SQL statement completes, whichever comes first.
       
  3310 **
       
  3311 ** SQLite is free to call the destructor and drop metadata on any
       
  3312 ** parameter of any function at any time.  The only guarantee is that
       
  3313 ** the destructor will be called before the metadata is dropped.
       
  3314 **
       
  3315 ** In practice, metadata is preserved between function calls for
       
  3316 ** expressions that are constant at compile time. This includes literal
       
  3317 ** values and SQL variables.
       
  3318 **
       
  3319 ** These routines must be called from the same thread in which
       
  3320 ** the SQL function is running.
       
  3321 **
       
  3322 ** Requirements:
       
  3323 ** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279]
       
  3324 */
       
  3325 void *sqlite3_get_auxdata(sqlite3_context*, int N);
       
  3326 void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
       
  3327 
       
  3328 
       
  3329 /*
       
  3330 ** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100>
       
  3331 **
       
  3332 ** These are special values for the destructor that is passed in as the
       
  3333 ** final argument to routines like [sqlite3_result_blob()].  If the destructor
       
  3334 ** argument is SQLITE_STATIC, it means that the content pointer is constant
       
  3335 ** and will never change.  It does not need to be destroyed.  The
       
  3336 ** SQLITE_TRANSIENT value means that the content will likely change in
       
  3337 ** the near future and that SQLite should make its own private copy of
       
  3338 ** the content before returning.
       
  3339 **
       
  3340 ** The typedef is necessary to work around problems in certain
       
  3341 ** C++ compilers.  See ticket #2191.
       
  3342 */
       
  3343 typedef void (*sqlite3_destructor_type)(void*);
       
  3344 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
       
  3345 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
       
  3346 
       
  3347 /*
       
  3348 ** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200>
       
  3349 **
       
  3350 ** These routines are used by the xFunc or xFinal callbacks that
       
  3351 ** implement SQL functions and aggregates.  See
       
  3352 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
       
  3353 ** for additional information.
       
  3354 **
       
  3355 ** These functions work very much like the [parameter binding] family of
       
  3356 ** functions used to bind values to host parameters in prepared statements.
       
  3357 ** Refer to the [SQL parameter] documentation for additional information.
       
  3358 **
       
  3359 ** The sqlite3_result_blob() interface sets the result from
       
  3360 ** an application-defined function to be the BLOB whose content is pointed
       
  3361 ** to by the second parameter and which is N bytes long where N is the
       
  3362 ** third parameter.
       
  3363 **
       
  3364 ** The sqlite3_result_zeroblob() interfaces set the result of
       
  3365 ** the application-defined function to be a BLOB containing all zero
       
  3366 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
       
  3367 **
       
  3368 ** The sqlite3_result_double() interface sets the result from
       
  3369 ** an application-defined function to be a floating point value specified
       
  3370 ** by its 2nd argument.
       
  3371 **
       
  3372 ** The sqlite3_result_error() and sqlite3_result_error16() functions
       
  3373 ** cause the implemented SQL function to throw an exception.
       
  3374 ** SQLite uses the string pointed to by the
       
  3375 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
       
  3376 ** as the text of an error message.  SQLite interprets the error
       
  3377 ** message string from sqlite3_result_error() as UTF-8. SQLite
       
  3378 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
       
  3379 ** byte order.  If the third parameter to sqlite3_result_error()
       
  3380 ** or sqlite3_result_error16() is negative then SQLite takes as the error
       
  3381 ** message all text up through the first zero character.
       
  3382 ** If the third parameter to sqlite3_result_error() or
       
  3383 ** sqlite3_result_error16() is non-negative then SQLite takes that many
       
  3384 ** bytes (not characters) from the 2nd parameter as the error message.
       
  3385 ** The sqlite3_result_error() and sqlite3_result_error16()
       
  3386 ** routines make a private copy of the error message text before
       
  3387 ** they return.  Hence, the calling function can deallocate or
       
  3388 ** modify the text after they return without harm.
       
  3389 ** The sqlite3_result_error_code() function changes the error code
       
  3390 ** returned by SQLite as a result of an error in a function.  By default,
       
  3391 ** the error code is SQLITE_ERROR.  A subsequent call to sqlite3_result_error()
       
  3392 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
       
  3393 **
       
  3394 ** The sqlite3_result_toobig() interface causes SQLite to throw an error
       
  3395 ** indicating that a string or BLOB is to long to represent.
       
  3396 **
       
  3397 ** The sqlite3_result_nomem() interface causes SQLite to throw an error
       
  3398 ** indicating that a memory allocation failed.
       
  3399 **
       
  3400 ** The sqlite3_result_int() interface sets the return value
       
  3401 ** of the application-defined function to be the 32-bit signed integer
       
  3402 ** value given in the 2nd argument.
       
  3403 ** The sqlite3_result_int64() interface sets the return value
       
  3404 ** of the application-defined function to be the 64-bit signed integer
       
  3405 ** value given in the 2nd argument.
       
  3406 **
       
  3407 ** The sqlite3_result_null() interface sets the return value
       
  3408 ** of the application-defined function to be NULL.
       
  3409 **
       
  3410 ** The sqlite3_result_text(), sqlite3_result_text16(),
       
  3411 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
       
  3412 ** set the return value of the application-defined function to be
       
  3413 ** a text string which is represented as UTF-8, UTF-16 native byte order,
       
  3414 ** UTF-16 little endian, or UTF-16 big endian, respectively.
       
  3415 ** SQLite takes the text result from the application from
       
  3416 ** the 2nd parameter of the sqlite3_result_text* interfaces.
       
  3417 ** If the 3rd parameter to the sqlite3_result_text* interfaces
       
  3418 ** is negative, then SQLite takes result text from the 2nd parameter
       
  3419 ** through the first zero character.
       
  3420 ** If the 3rd parameter to the sqlite3_result_text* interfaces
       
  3421 ** is non-negative, then as many bytes (not characters) of the text
       
  3422 ** pointed to by the 2nd parameter are taken as the application-defined
       
  3423 ** function result.
       
  3424 ** If the 4th parameter to the sqlite3_result_text* interfaces
       
  3425 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
       
  3426 ** function as the destructor on the text or BLOB result when it has
       
  3427 ** finished using that result.
       
  3428 ** If the 4th parameter to the sqlite3_result_text* interfaces or
       
  3429 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
       
  3430 ** assumes that the text or BLOB result is in constant space and does not
       
  3431 ** copy the it or call a destructor when it has finished using that result.
       
  3432 ** If the 4th parameter to the sqlite3_result_text* interfaces
       
  3433 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
       
  3434 ** then SQLite makes a copy of the result into space obtained from
       
  3435 ** from [sqlite3_malloc()] before it returns.
       
  3436 **
       
  3437 ** The sqlite3_result_value() interface sets the result of
       
  3438 ** the application-defined function to be a copy the
       
  3439 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  The
       
  3440 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
       
  3441 ** so that the [sqlite3_value] specified in the parameter may change or
       
  3442 ** be deallocated after sqlite3_result_value() returns without harm.
       
  3443 ** A [protected sqlite3_value] object may always be used where an
       
  3444 ** [unprotected sqlite3_value] object is required, so either
       
  3445 ** kind of [sqlite3_value] object can be used with this interface.
       
  3446 **
       
  3447 ** If these routines are called from within the different thread
       
  3448 ** than the one containing the application-defined function that received
       
  3449 ** the [sqlite3_context] pointer, the results are undefined.
       
  3450 **
       
  3451 ** Requirements:
       
  3452 ** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424]
       
  3453 ** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448]
       
  3454 ** [H16451] [H16454] [H16457] [H16460] [H16463]
       
  3455 */
       
  3456 void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
       
  3457 void sqlite3_result_double(sqlite3_context*, double);
       
  3458 void sqlite3_result_error(sqlite3_context*, const char*, int);
       
  3459 void sqlite3_result_error16(sqlite3_context*, const void*, int);
       
  3460 void sqlite3_result_error_toobig(sqlite3_context*);
       
  3461 void sqlite3_result_error_nomem(sqlite3_context*);
       
  3462 void sqlite3_result_error_code(sqlite3_context*, int);
       
  3463 void sqlite3_result_int(sqlite3_context*, int);
       
  3464 void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
       
  3465 void sqlite3_result_null(sqlite3_context*);
       
  3466 void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
       
  3467 void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
       
  3468 void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
       
  3469 void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
       
  3470 void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
       
  3471 void sqlite3_result_zeroblob(sqlite3_context*, int n);
       
  3472 
       
  3473 /*
       
  3474 ** CAPI3REF: Define New Collating Sequences {H16600} <S20300>
       
  3475 **
       
  3476 ** These functions are used to add new collation sequences to the
       
  3477 ** [database connection] specified as the first argument.
       
  3478 **
       
  3479 ** The name of the new collation sequence is specified as a UTF-8 string
       
  3480 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
       
  3481 ** and a UTF-16 string for sqlite3_create_collation16(). In all cases
       
  3482 ** the name is passed as the second function argument.
       
  3483 **
       
  3484 ** The third argument may be one of the constants [SQLITE_UTF8],
       
  3485 ** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied
       
  3486 ** routine expects to be passed pointers to strings encoded using UTF-8,
       
  3487 ** UTF-16 little-endian, or UTF-16 big-endian, respectively. The
       
  3488 ** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that
       
  3489 ** the routine expects pointers to 16-bit word aligned strings
       
  3490 ** of UTF-16 in the native byte order of the host computer.
       
  3491 **
       
  3492 ** A pointer to the user supplied routine must be passed as the fifth
       
  3493 ** argument.  If it is NULL, this is the same as deleting the collation
       
  3494 ** sequence (so that SQLite cannot call it anymore).
       
  3495 ** Each time the application supplied function is invoked, it is passed
       
  3496 ** as its first parameter a copy of the void* passed as the fourth argument
       
  3497 ** to sqlite3_create_collation() or sqlite3_create_collation16().
       
  3498 **
       
  3499 ** The remaining arguments to the application-supplied routine are two strings,
       
  3500 ** each represented by a (length, data) pair and encoded in the encoding
       
  3501 ** that was passed as the third argument when the collation sequence was
       
  3502 ** registered. {END}  The application defined collation routine should
       
  3503 ** return negative, zero or positive if the first string is less than,
       
  3504 ** equal to, or greater than the second string. i.e. (STRING1 - STRING2).
       
  3505 **
       
  3506 ** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
       
  3507 ** except that it takes an extra argument which is a destructor for
       
  3508 ** the collation.  The destructor is called when the collation is
       
  3509 ** destroyed and is passed a copy of the fourth parameter void* pointer
       
  3510 ** of the sqlite3_create_collation_v2().
       
  3511 ** Collations are destroyed when they are overridden by later calls to the
       
  3512 ** collation creation functions or when the [database connection] is closed
       
  3513 ** using [sqlite3_close()].
       
  3514 **
       
  3515 ** Requirements:
       
  3516 ** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621]
       
  3517 ** [H16624] [H16627] [H16630]
       
  3518 */
       
  3519 int sqlite3_create_collation(
       
  3520   sqlite3*, 
       
  3521   const char *zName, 
       
  3522   int eTextRep, 
       
  3523   void*,
       
  3524   int(*xCompare)(void*,int,const void*,int,const void*)
       
  3525 );
       
  3526 int sqlite3_create_collation_v2(
       
  3527   sqlite3*, 
       
  3528   const char *zName, 
       
  3529   int eTextRep, 
       
  3530   void*,
       
  3531   int(*xCompare)(void*,int,const void*,int,const void*),
       
  3532   void(*xDestroy)(void*)
       
  3533 );
       
  3534 int sqlite3_create_collation16(
       
  3535   sqlite3*, 
       
  3536   const void *zName,
       
  3537   int eTextRep, 
       
  3538   void*,
       
  3539   int(*xCompare)(void*,int,const void*,int,const void*)
       
  3540 );
       
  3541 
       
  3542 /*
       
  3543 ** CAPI3REF: Collation Needed Callbacks {H16700} <S20300>
       
  3544 **
       
  3545 ** To avoid having to register all collation sequences before a database
       
  3546 ** can be used, a single callback function may be registered with the
       
  3547 ** [database connection] to be called whenever an undefined collation
       
  3548 ** sequence is required.
       
  3549 **
       
  3550 ** If the function is registered using the sqlite3_collation_needed() API,
       
  3551 ** then it is passed the names of undefined collation sequences as strings
       
  3552 ** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used,
       
  3553 ** the names are passed as UTF-16 in machine native byte order.
       
  3554 ** A call to either function replaces any existing callback.
       
  3555 **
       
  3556 ** When the callback is invoked, the first argument passed is a copy
       
  3557 ** of the second argument to sqlite3_collation_needed() or
       
  3558 ** sqlite3_collation_needed16().  The second argument is the database
       
  3559 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
       
  3560 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
       
  3561 ** sequence function required.  The fourth parameter is the name of the
       
  3562 ** required collation sequence.
       
  3563 **
       
  3564 ** The callback function should register the desired collation using
       
  3565 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
       
  3566 ** [sqlite3_create_collation_v2()].
       
  3567 **
       
  3568 ** Requirements:
       
  3569 ** [H16702] [H16704] [H16706]
       
  3570 */
       
  3571 int sqlite3_collation_needed(
       
  3572   sqlite3*, 
       
  3573   void*, 
       
  3574   void(*)(void*,sqlite3*,int eTextRep,const char*)
       
  3575 );
       
  3576 int sqlite3_collation_needed16(
       
  3577   sqlite3*, 
       
  3578   void*,
       
  3579   void(*)(void*,sqlite3*,int eTextRep,const void*)
       
  3580 );
       
  3581 
       
  3582 /*
       
  3583 ** Specify the key for an encrypted database.  This routine should be
       
  3584 ** called right after sqlite3_open().
       
  3585 **
       
  3586 ** The code to implement this API is not available in the public release
       
  3587 ** of SQLite.
       
  3588 */
       
  3589 int sqlite3_key(
       
  3590   sqlite3 *db,                   /* Database to be rekeyed */
       
  3591   const void *pKey, int nKey     /* The key */
       
  3592 );
       
  3593 
       
  3594 /*
       
  3595 ** Change the key on an open database.  If the current database is not
       
  3596 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
       
  3597 ** database is decrypted.
       
  3598 **
       
  3599 ** The code to implement this API is not available in the public release
       
  3600 ** of SQLite.
       
  3601 */
       
  3602 int sqlite3_rekey(
       
  3603   sqlite3 *db,                   /* Database to be rekeyed */
       
  3604   const void *pKey, int nKey     /* The new key */
       
  3605 );
       
  3606 
       
  3607 /*
       
  3608 ** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410>
       
  3609 **
       
  3610 ** The sqlite3_sleep() function causes the current thread to suspend execution
       
  3611 ** for at least a number of milliseconds specified in its parameter.
       
  3612 **
       
  3613 ** If the operating system does not support sleep requests with
       
  3614 ** millisecond time resolution, then the time will be rounded up to
       
  3615 ** the nearest second. The number of milliseconds of sleep actually
       
  3616 ** requested from the operating system is returned.
       
  3617 **
       
  3618 ** SQLite implements this interface by calling the xSleep()
       
  3619 ** method of the default [sqlite3_vfs] object.
       
  3620 **
       
  3621 ** Requirements: [H10533] [H10536]
       
  3622 */
       
  3623 int sqlite3_sleep(int);
       
  3624 
       
  3625 /*
       
  3626 ** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000>
       
  3627 **
       
  3628 ** If this global variable is made to point to a string which is
       
  3629 ** the name of a folder (a.k.a. directory), then all temporary files
       
  3630 ** created by SQLite will be placed in that directory.  If this variable
       
  3631 ** is a NULL pointer, then SQLite performs a search for an appropriate
       
  3632 ** temporary file directory.
       
  3633 **
       
  3634 ** It is not safe to modify this variable once a [database connection]
       
  3635 ** has been opened.  It is intended that this variable be set once
       
  3636 ** as part of process initialization and before any SQLite interface
       
  3637 ** routines have been call and remain unchanged thereafter.
       
  3638 */
       
  3639 SQLITE_EXTERN char *sqlite3_temp_directory;
       
  3640 
       
  3641 /*
       
  3642 ** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200>
       
  3643 ** KEYWORDS: {autocommit mode}
       
  3644 **
       
  3645 ** The sqlite3_get_autocommit() interface returns non-zero or
       
  3646 ** zero if the given database connection is or is not in autocommit mode,
       
  3647 ** respectively.  Autocommit mode is on by default.
       
  3648 ** Autocommit mode is disabled by a [BEGIN] statement.
       
  3649 ** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
       
  3650 **
       
  3651 ** If certain kinds of errors occur on a statement within a multi-statement
       
  3652 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
       
  3653 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
       
  3654 ** transaction might be rolled back automatically.  The only way to
       
  3655 ** find out whether SQLite automatically rolled back the transaction after
       
  3656 ** an error is to use this function.
       
  3657 **
       
  3658 ** If another thread changes the autocommit status of the database
       
  3659 ** connection while this routine is running, then the return value
       
  3660 ** is undefined.
       
  3661 **
       
  3662 ** Requirements: [H12931] [H12932] [H12933] [H12934]
       
  3663 */
       
  3664 int sqlite3_get_autocommit(sqlite3*);
       
  3665 
       
  3666 /*
       
  3667 ** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600>
       
  3668 **
       
  3669 ** The sqlite3_db_handle interface returns the [database connection] handle
       
  3670 ** to which a [prepared statement] belongs.  The [database connection]
       
  3671 ** returned by sqlite3_db_handle is the same [database connection] that was the first argument
       
  3672 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
       
  3673 ** create the statement in the first place.
       
  3674 **
       
  3675 ** Requirements: [H13123]
       
  3676 */
       
  3677 sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
       
  3678 
       
  3679 /*
       
  3680 ** CAPI3REF: Find the next prepared statement {H13140} <S60600>
       
  3681 **
       
  3682 ** This interface returns a pointer to the next [prepared statement] after
       
  3683 ** pStmt associated with the [database connection] pDb.  If pStmt is NULL
       
  3684 ** then this interface returns a pointer to the first prepared statement
       
  3685 ** associated with the database connection pDb.  If no prepared statement
       
  3686 ** satisfies the conditions of this routine, it returns NULL.
       
  3687 **
       
  3688 ** The [database connection] pointer D in a call to
       
  3689 ** [sqlite3_next_stmt(D,S)] must refer to an open database
       
  3690 ** connection and in particular must not be a NULL pointer.
       
  3691 **
       
  3692 ** Requirements: [H13143] [H13146] [H13149] [H13152]
       
  3693 */
       
  3694 sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
       
  3695 
       
  3696 /*
       
  3697 ** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400>
       
  3698 **
       
  3699 ** The sqlite3_commit_hook() interface registers a callback
       
  3700 ** function to be invoked whenever a transaction is committed.
       
  3701 ** Any callback set by a previous call to sqlite3_commit_hook()
       
  3702 ** for the same database connection is overridden.
       
  3703 ** The sqlite3_rollback_hook() interface registers a callback
       
  3704 ** function to be invoked whenever a transaction is committed.
       
  3705 ** Any callback set by a previous call to sqlite3_commit_hook()
       
  3706 ** for the same database connection is overridden.
       
  3707 ** The pArg argument is passed through to the callback.
       
  3708 ** If the callback on a commit hook function returns non-zero,
       
  3709 ** then the commit is converted into a rollback.
       
  3710 **
       
  3711 ** If another function was previously registered, its
       
  3712 ** pArg value is returned.  Otherwise NULL is returned.
       
  3713 **
       
  3714 ** The callback implementation must not do anything that will modify
       
  3715 ** the database connection that invoked the callback.  Any actions
       
  3716 ** to modify the database connection must be deferred until after the
       
  3717 ** completion of the [sqlite3_step()] call that triggered the commit
       
  3718 ** or rollback hook in the first place.
       
  3719 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  3720 ** database connections for the meaning of "modify" in this paragraph.
       
  3721 **
       
  3722 ** Registering a NULL function disables the callback.
       
  3723 **
       
  3724 ** For the purposes of this API, a transaction is said to have been
       
  3725 ** rolled back if an explicit "ROLLBACK" statement is executed, or
       
  3726 ** an error or constraint causes an implicit rollback to occur.
       
  3727 ** The rollback callback is not invoked if a transaction is
       
  3728 ** automatically rolled back because the database connection is closed.
       
  3729 ** The rollback callback is not invoked if a transaction is
       
  3730 ** rolled back because a commit callback returned non-zero.
       
  3731 ** <todo> Check on this </todo>
       
  3732 **
       
  3733 ** Requirements:
       
  3734 ** [H12951] [H12952] [H12953] [H12954] [H12955]
       
  3735 ** [H12961] [H12962] [H12963] [H12964]
       
  3736 */
       
  3737 void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
       
  3738 void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
       
  3739 
       
  3740 /*
       
  3741 ** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400>
       
  3742 **
       
  3743 ** The sqlite3_update_hook() interface registers a callback function
       
  3744 ** with the [database connection] identified by the first argument
       
  3745 ** to be invoked whenever a row is updated, inserted or deleted.
       
  3746 ** Any callback set by a previous call to this function
       
  3747 ** for the same database connection is overridden.
       
  3748 **
       
  3749 ** The second argument is a pointer to the function to invoke when a
       
  3750 ** row is updated, inserted or deleted.
       
  3751 ** The first argument to the callback is a copy of the third argument
       
  3752 ** to sqlite3_update_hook().
       
  3753 ** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
       
  3754 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
       
  3755 ** to be invoked.
       
  3756 ** The third and fourth arguments to the callback contain pointers to the
       
  3757 ** database and table name containing the affected row.
       
  3758 ** The final callback parameter is the [rowid] of the row.
       
  3759 ** In the case of an update, this is the [rowid] after the update takes place.
       
  3760 **
       
  3761 ** The update hook is not invoked when internal system tables are
       
  3762 ** modified (i.e. sqlite_master and sqlite_sequence).
       
  3763 **
       
  3764 ** The update hook implementation must not do anything that will modify
       
  3765 ** the database connection that invoked the update hook.  Any actions
       
  3766 ** to modify the database connection must be deferred until after the
       
  3767 ** completion of the [sqlite3_step()] call that triggered the update hook.
       
  3768 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
       
  3769 ** database connections for the meaning of "modify" in this paragraph.
       
  3770 **
       
  3771 ** If another function was previously registered, its pArg value
       
  3772 ** is returned.  Otherwise NULL is returned.
       
  3773 **
       
  3774 ** Requirements:
       
  3775 ** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986]
       
  3776 */
       
  3777 void *sqlite3_update_hook(
       
  3778   sqlite3*, 
       
  3779   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
       
  3780   void*
       
  3781 );
       
  3782 
       
  3783 /*
       
  3784 ** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900>
       
  3785 ** KEYWORDS: {shared cache} {shared cache mode}
       
  3786 **
       
  3787 ** This routine enables or disables the sharing of the database cache
       
  3788 ** and schema data structures between [database connection | connections]
       
  3789 ** to the same database. Sharing is enabled if the argument is true
       
  3790 ** and disabled if the argument is false.
       
  3791 **
       
  3792 ** Cache sharing is enabled and disabled for an entire process.
       
  3793 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
       
  3794 ** sharing was enabled or disabled for each thread separately.
       
  3795 **
       
  3796 ** The cache sharing mode set by this interface effects all subsequent
       
  3797 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
       
  3798 ** Existing database connections continue use the sharing mode
       
  3799 ** that was in effect at the time they were opened.
       
  3800 **
       
  3801 ** Virtual tables cannot be used with a shared cache.  When shared
       
  3802 ** cache is enabled, the [sqlite3_create_module()] API used to register
       
  3803 ** virtual tables will always return an error.
       
  3804 **
       
  3805 ** This routine returns [SQLITE_OK] if shared cache was enabled or disabled
       
  3806 ** successfully.  An [error code] is returned otherwise.
       
  3807 **
       
  3808 ** Shared cache is disabled by default. But this might change in
       
  3809 ** future releases of SQLite.  Applications that care about shared
       
  3810 ** cache setting should set it explicitly.
       
  3811 **
       
  3812 ** See Also:  [SQLite Shared-Cache Mode]
       
  3813 **
       
  3814 ** Requirements: [H10331] [H10336] [H10337] [H10339]
       
  3815 */
       
  3816 int sqlite3_enable_shared_cache(int);
       
  3817 
       
  3818 /*
       
  3819 ** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220>
       
  3820 **
       
  3821 ** The sqlite3_release_memory() interface attempts to free N bytes
       
  3822 ** of heap memory by deallocating non-essential memory allocations
       
  3823 ** held by the database library. {END}  Memory used to cache database
       
  3824 ** pages to improve performance is an example of non-essential memory.
       
  3825 ** sqlite3_release_memory() returns the number of bytes actually freed,
       
  3826 ** which might be more or less than the amount requested.
       
  3827 **
       
  3828 ** Requirements: [H17341] [H17342]
       
  3829 */
       
  3830 int sqlite3_release_memory(int);
       
  3831 
       
  3832 /*
       
  3833 ** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220>
       
  3834 **
       
  3835 ** The sqlite3_soft_heap_limit() interface places a "soft" limit
       
  3836 ** on the amount of heap memory that may be allocated by SQLite.
       
  3837 ** If an internal allocation is requested that would exceed the
       
  3838 ** soft heap limit, [sqlite3_release_memory()] is invoked one or
       
  3839 ** more times to free up some space before the allocation is performed.
       
  3840 **
       
  3841 ** The limit is called "soft", because if [sqlite3_release_memory()]
       
  3842 ** cannot free sufficient memory to prevent the limit from being exceeded,
       
  3843 ** the memory is allocated anyway and the current operation proceeds.
       
  3844 **
       
  3845 ** A negative or zero value for N means that there is no soft heap limit and
       
  3846 ** [sqlite3_release_memory()] will only be called when memory is exhausted.
       
  3847 ** The default value for the soft heap limit is zero.
       
  3848 **
       
  3849 ** SQLite makes a best effort to honor the soft heap limit.
       
  3850 ** But if the soft heap limit cannot be honored, execution will
       
  3851 ** continue without error or notification.  This is why the limit is
       
  3852 ** called a "soft" limit.  It is advisory only.
       
  3853 **
       
  3854 ** Prior to SQLite version 3.5.0, this routine only constrained the memory
       
  3855 ** allocated by a single thread - the same thread in which this routine
       
  3856 ** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
       
  3857 ** applied to all threads. The value specified for the soft heap limit
       
  3858 ** is an upper bound on the total memory allocation for all threads. In
       
  3859 ** version 3.5.0 there is no mechanism for limiting the heap usage for
       
  3860 ** individual threads.
       
  3861 **
       
  3862 ** Requirements:
       
  3863 ** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358]
       
  3864 */
       
  3865 void sqlite3_soft_heap_limit(int);
       
  3866 
       
  3867 /*
       
  3868 ** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300>
       
  3869 **
       
  3870 ** This routine returns metadata about a specific column of a specific
       
  3871 ** database table accessible using the [database connection] handle
       
  3872 ** passed as the first function argument.
       
  3873 **
       
  3874 ** The column is identified by the second, third and fourth parameters to
       
  3875 ** this function. The second parameter is either the name of the database
       
  3876 ** (i.e. "main", "temp" or an attached database) containing the specified
       
  3877 ** table or NULL. If it is NULL, then all attached databases are searched
       
  3878 ** for the table using the same algorithm used by the database engine to
       
  3879 ** resolve unqualified table references.
       
  3880 **
       
  3881 ** The third and fourth parameters to this function are the table and column
       
  3882 ** name of the desired column, respectively. Neither of these parameters
       
  3883 ** may be NULL.
       
  3884 **
       
  3885 ** Metadata is returned by writing to the memory locations passed as the 5th
       
  3886 ** and subsequent parameters to this function. Any of these arguments may be
       
  3887 ** NULL, in which case the corresponding element of metadata is omitted.
       
  3888 **
       
  3889 ** <blockquote>
       
  3890 ** <table border="1">
       
  3891 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
       
  3892 **
       
  3893 ** <tr><td> 5th <td> const char* <td> Data type
       
  3894 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
       
  3895 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
       
  3896 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
       
  3897 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
       
  3898 ** </table>
       
  3899 ** </blockquote>
       
  3900 **
       
  3901 ** The memory pointed to by the character pointers returned for the
       
  3902 ** declaration type and collation sequence is valid only until the next
       
  3903 ** call to any SQLite API function.
       
  3904 **
       
  3905 ** If the specified table is actually a view, an [error code] is returned.
       
  3906 **
       
  3907 ** If the specified column is "rowid", "oid" or "_rowid_" and an
       
  3908 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
       
  3909 ** parameters are set for the explicitly declared column. If there is no
       
  3910 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output
       
  3911 ** parameters are set as follows:
       
  3912 **
       
  3913 ** <pre>
       
  3914 **     data type: "INTEGER"
       
  3915 **     collation sequence: "BINARY"
       
  3916 **     not null: 0
       
  3917 **     primary key: 1
       
  3918 **     auto increment: 0
       
  3919 ** </pre>
       
  3920 **
       
  3921 ** This function may load one or more schemas from database files. If an
       
  3922 ** error occurs during this process, or if the requested table or column
       
  3923 ** cannot be found, an [error code] is returned and an error message left
       
  3924 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).
       
  3925 **
       
  3926 ** This API is only available if the library was compiled with the
       
  3927 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined.
       
  3928 */
       
  3929 int sqlite3_table_column_metadata(
       
  3930   sqlite3 *db,                /* Connection handle */
       
  3931   const char *zDbName,        /* Database name or NULL */
       
  3932   const char *zTableName,     /* Table name */
       
  3933   const char *zColumnName,    /* Column name */
       
  3934   char const **pzDataType,    /* OUTPUT: Declared data type */
       
  3935   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
       
  3936   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
       
  3937   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
       
  3938   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
       
  3939 );
       
  3940 
       
  3941 /*
       
  3942 ** CAPI3REF: Load An Extension {H12600} <S20500>
       
  3943 **
       
  3944 ** This interface loads an SQLite extension library from the named file.
       
  3945 **
       
  3946 ** {H12601} The sqlite3_load_extension() interface attempts to load an
       
  3947 **          SQLite extension library contained in the file zFile.
       
  3948 **
       
  3949 ** {H12602} The entry point is zProc.
       
  3950 **
       
  3951 ** {H12603} zProc may be 0, in which case the name of the entry point
       
  3952 **          defaults to "sqlite3_extension_init".
       
  3953 **
       
  3954 ** {H12604} The sqlite3_load_extension() interface shall return
       
  3955 **          [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
       
  3956 **
       
  3957 ** {H12605} If an error occurs and pzErrMsg is not 0, then the
       
  3958 **          [sqlite3_load_extension()] interface shall attempt to
       
  3959 **          fill *pzErrMsg with error message text stored in memory
       
  3960 **          obtained from [sqlite3_malloc()]. {END}  The calling function
       
  3961 **          should free this memory by calling [sqlite3_free()].
       
  3962 **
       
  3963 ** {H12606} Extension loading must be enabled using
       
  3964 **          [sqlite3_enable_load_extension()] prior to calling this API,
       
  3965 **          otherwise an error will be returned.
       
  3966 */
       
  3967 int sqlite3_load_extension(
       
  3968   sqlite3 *db,          /* Load the extension into this database connection */
       
  3969   const char *zFile,    /* Name of the shared library containing extension */
       
  3970   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
       
  3971   char **pzErrMsg       /* Put error message here if not 0 */
       
  3972 );
       
  3973 
       
  3974 /*
       
  3975 ** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500>
       
  3976 **
       
  3977 ** So as not to open security holes in older applications that are
       
  3978 ** unprepared to deal with extension loading, and as a means of disabling
       
  3979 ** extension loading while evaluating user-entered SQL, the following API
       
  3980 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
       
  3981 **
       
  3982 ** Extension loading is off by default. See ticket #1863.
       
  3983 **
       
  3984 ** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1
       
  3985 **          to turn extension loading on and call it with onoff==0 to turn
       
  3986 **          it back off again.
       
  3987 **
       
  3988 ** {H12622} Extension loading is off by default.
       
  3989 */
       
  3990 int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
       
  3991 
       
  3992 /*
       
  3993 ** CAPI3REF: Automatically Load An Extensions {H12640} <S20500>
       
  3994 **
       
  3995 ** This API can be invoked at program startup in order to register
       
  3996 ** one or more statically linked extensions that will be available
       
  3997 ** to all new [database connections]. {END}
       
  3998 **
       
  3999 ** This routine stores a pointer to the extension in an array that is
       
  4000 ** obtained from [sqlite3_malloc()].  If you run a memory leak checker
       
  4001 ** on your program and it reports a leak because of this array, invoke
       
  4002 ** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory.
       
  4003 **
       
  4004 ** {H12641} This function registers an extension entry point that is
       
  4005 **          automatically invoked whenever a new [database connection]
       
  4006 **          is opened using [sqlite3_open()], [sqlite3_open16()],
       
  4007 **          or [sqlite3_open_v2()].
       
  4008 **
       
  4009 ** {H12642} Duplicate extensions are detected so calling this routine
       
  4010 **          multiple times with the same extension is harmless.
       
  4011 **
       
  4012 ** {H12643} This routine stores a pointer to the extension in an array
       
  4013 **          that is obtained from [sqlite3_malloc()].
       
  4014 **
       
  4015 ** {H12644} Automatic extensions apply across all threads.
       
  4016 */
       
  4017 int sqlite3_auto_extension(void (*xEntryPoint)(void));
       
  4018 
       
  4019 /*
       
  4020 ** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500>
       
  4021 **
       
  4022 ** This function disables all previously registered automatic
       
  4023 ** extensions. {END}  It undoes the effect of all prior
       
  4024 ** [sqlite3_auto_extension()] calls.
       
  4025 **
       
  4026 ** {H12661} This function disables all previously registered
       
  4027 **          automatic extensions.
       
  4028 **
       
  4029 ** {H12662} This function disables automatic extensions in all threads.
       
  4030 */
       
  4031 void sqlite3_reset_auto_extension(void);
       
  4032 
       
  4033 /*
       
  4034 ****** EXPERIMENTAL - subject to change without notice **************
       
  4035 **
       
  4036 ** The interface to the virtual-table mechanism is currently considered
       
  4037 ** to be experimental.  The interface might change in incompatible ways.
       
  4038 ** If this is a problem for you, do not use the interface at this time.
       
  4039 **
       
  4040 ** When the virtual-table mechanism stabilizes, we will declare the
       
  4041 ** interface fixed, support it indefinitely, and remove this comment.
       
  4042 */
       
  4043 
       
  4044 /*
       
  4045 ** Structures used by the virtual table interface
       
  4046 */
       
  4047 typedef struct sqlite3_vtab sqlite3_vtab;
       
  4048 typedef struct sqlite3_index_info sqlite3_index_info;
       
  4049 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
       
  4050 typedef struct sqlite3_module sqlite3_module;
       
  4051 
       
  4052 /*
       
  4053 ** CAPI3REF: Virtual Table Object {H18000} <S20400>
       
  4054 ** KEYWORDS: sqlite3_module
       
  4055 ** EXPERIMENTAL
       
  4056 **
       
  4057 ** A module is a class of virtual tables.  Each module is defined
       
  4058 ** by an instance of the following structure.  This structure consists
       
  4059 ** mostly of methods for the module.
       
  4060 **
       
  4061 ** This interface is experimental and is subject to change or
       
  4062 ** removal in future releases of SQLite.
       
  4063 */
       
  4064 struct sqlite3_module {
       
  4065   int iVersion;
       
  4066   int (*xCreate)(sqlite3*, void *pAux,
       
  4067                int argc, const char *const*argv,
       
  4068                sqlite3_vtab **ppVTab, char**);
       
  4069   int (*xConnect)(sqlite3*, void *pAux,
       
  4070                int argc, const char *const*argv,
       
  4071                sqlite3_vtab **ppVTab, char**);
       
  4072   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
       
  4073   int (*xDisconnect)(sqlite3_vtab *pVTab);
       
  4074   int (*xDestroy)(sqlite3_vtab *pVTab);
       
  4075   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
       
  4076   int (*xClose)(sqlite3_vtab_cursor*);
       
  4077   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
       
  4078                 int argc, sqlite3_value **argv);
       
  4079   int (*xNext)(sqlite3_vtab_cursor*);
       
  4080   int (*xEof)(sqlite3_vtab_cursor*);
       
  4081   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
       
  4082   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
       
  4083   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
       
  4084   int (*xBegin)(sqlite3_vtab *pVTab);
       
  4085   int (*xSync)(sqlite3_vtab *pVTab);
       
  4086   int (*xCommit)(sqlite3_vtab *pVTab);
       
  4087   int (*xRollback)(sqlite3_vtab *pVTab);
       
  4088   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
       
  4089                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
       
  4090                        void **ppArg);
       
  4091   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
       
  4092 };
       
  4093 
       
  4094 /*
       
  4095 ** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400>
       
  4096 ** KEYWORDS: sqlite3_index_info
       
  4097 ** EXPERIMENTAL
       
  4098 **
       
  4099 ** The sqlite3_index_info structure and its substructures is used to
       
  4100 ** pass information into and receive the reply from the xBestIndex
       
  4101 ** method of an sqlite3_module.  The fields under **Inputs** are the
       
  4102 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
       
  4103 ** results into the **Outputs** fields.
       
  4104 **
       
  4105 ** The aConstraint[] array records WHERE clause constraints of the form:
       
  4106 **
       
  4107 ** <pre>column OP expr</pre>
       
  4108 **
       
  4109 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.  The particular operator is
       
  4110 ** stored in aConstraint[].op.  The index of the column is stored in
       
  4111 ** aConstraint[].iColumn.  aConstraint[].usable is TRUE if the
       
  4112 ** expr on the right-hand side can be evaluated (and thus the constraint
       
  4113 ** is usable) and false if it cannot.
       
  4114 **
       
  4115 ** The optimizer automatically inverts terms of the form "expr OP column"
       
  4116 ** and makes other simplifications to the WHERE clause in an attempt to
       
  4117 ** get as many WHERE clause terms into the form shown above as possible.
       
  4118 ** The aConstraint[] array only reports WHERE clause terms in the correct
       
  4119 ** form that refer to the particular virtual table being queried.
       
  4120 **
       
  4121 ** Information about the ORDER BY clause is stored in aOrderBy[].
       
  4122 ** Each term of aOrderBy records a column of the ORDER BY clause.
       
  4123 **
       
  4124 ** The xBestIndex method must fill aConstraintUsage[] with information
       
  4125 ** about what parameters to pass to xFilter.  If argvIndex>0 then
       
  4126 ** the right-hand side of the corresponding aConstraint[] is evaluated
       
  4127 ** and becomes the argvIndex-th entry in argv.  If aConstraintUsage[].omit
       
  4128 ** is true, then the constraint is assumed to be fully handled by the
       
  4129 ** virtual table and is not checked again by SQLite.
       
  4130 **
       
  4131 ** The idxNum and idxPtr values are recorded and passed into xFilter.
       
  4132 ** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true.
       
  4133 **
       
  4134 ** The orderByConsumed means that output from xFilter will occur in
       
  4135 ** the correct order to satisfy the ORDER BY clause so that no separate
       
  4136 ** sorting step is required.
       
  4137 **
       
  4138 ** The estimatedCost value is an estimate of the cost of doing the
       
  4139 ** particular lookup.  A full scan of a table with N entries should have
       
  4140 ** a cost of N.  A binary search of a table of N entries should have a
       
  4141 ** cost of approximately log(N).
       
  4142 **
       
  4143 ** This interface is experimental and is subject to change or
       
  4144 ** removal in future releases of SQLite.
       
  4145 */
       
  4146 struct sqlite3_index_info {
       
  4147   /* Inputs */
       
  4148   int nConstraint;           /* Number of entries in aConstraint */
       
  4149   struct sqlite3_index_constraint {
       
  4150      int iColumn;              /* Column on left-hand side of constraint */
       
  4151      unsigned char op;         /* Constraint operator */
       
  4152      unsigned char usable;     /* True if this constraint is usable */
       
  4153      int iTermOffset;          /* Used internally - xBestIndex should ignore */
       
  4154   } *aConstraint;            /* Table of WHERE clause constraints */
       
  4155   int nOrderBy;              /* Number of terms in the ORDER BY clause */
       
  4156   struct sqlite3_index_orderby {
       
  4157      int iColumn;              /* Column number */
       
  4158      unsigned char desc;       /* True for DESC.  False for ASC. */
       
  4159   } *aOrderBy;               /* The ORDER BY clause */
       
  4160   /* Outputs */
       
  4161   struct sqlite3_index_constraint_usage {
       
  4162     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
       
  4163     unsigned char omit;      /* Do not code a test for this constraint */
       
  4164   } *aConstraintUsage;
       
  4165   int idxNum;                /* Number used to identify the index */
       
  4166   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
       
  4167   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
       
  4168   int orderByConsumed;       /* True if output is already ordered */
       
  4169   double estimatedCost;      /* Estimated cost of using this index */
       
  4170 };
       
  4171 #define SQLITE_INDEX_CONSTRAINT_EQ    2
       
  4172 #define SQLITE_INDEX_CONSTRAINT_GT    4
       
  4173 #define SQLITE_INDEX_CONSTRAINT_LE    8
       
  4174 #define SQLITE_INDEX_CONSTRAINT_LT    16
       
  4175 #define SQLITE_INDEX_CONSTRAINT_GE    32
       
  4176 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
       
  4177 
       
  4178 /*
       
  4179 ** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400>
       
  4180 ** EXPERIMENTAL
       
  4181 **
       
  4182 ** This routine is used to register a new module name with a
       
  4183 ** [database connection].  Module names must be registered before
       
  4184 ** creating new virtual tables on the module, or before using
       
  4185 ** preexisting virtual tables of the module.
       
  4186 **
       
  4187 ** This interface is experimental and is subject to change or
       
  4188 ** removal in future releases of SQLite.
       
  4189 */
       
  4190 SQLITE_EXPERIMENTAL int sqlite3_create_module(
       
  4191   sqlite3 *db,               /* SQLite connection to register module with */
       
  4192   const char *zName,         /* Name of the module */
       
  4193   const sqlite3_module *,    /* Methods for the module */
       
  4194   void *                     /* Client data for xCreate/xConnect */
       
  4195 );
       
  4196 
       
  4197 /*
       
  4198 ** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400>
       
  4199 ** EXPERIMENTAL
       
  4200 **
       
  4201 ** This routine is identical to the [sqlite3_create_module()] method above,
       
  4202 ** except that it allows a destructor function to be specified. It is
       
  4203 ** even more experimental than the rest of the virtual tables API.
       
  4204 */
       
  4205 SQLITE_EXPERIMENTAL int sqlite3_create_module_v2(
       
  4206   sqlite3 *db,               /* SQLite connection to register module with */
       
  4207   const char *zName,         /* Name of the module */
       
  4208   const sqlite3_module *,    /* Methods for the module */
       
  4209   void *,                    /* Client data for xCreate/xConnect */
       
  4210   void(*xDestroy)(void*)     /* Module destructor function */
       
  4211 );
       
  4212 
       
  4213 /*
       
  4214 ** CAPI3REF: Virtual Table Instance Object {H18010} <S20400>
       
  4215 ** KEYWORDS: sqlite3_vtab
       
  4216 ** EXPERIMENTAL
       
  4217 **
       
  4218 ** Every module implementation uses a subclass of the following structure
       
  4219 ** to describe a particular instance of the module.  Each subclass will
       
  4220 ** be tailored to the specific needs of the module implementation.
       
  4221 ** The purpose of this superclass is to define certain fields that are
       
  4222 ** common to all module implementations.
       
  4223 **
       
  4224 ** Virtual tables methods can set an error message by assigning a
       
  4225 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
       
  4226 ** take care that any prior string is freed by a call to [sqlite3_free()]
       
  4227 ** prior to assigning a new string to zErrMsg.  After the error message
       
  4228 ** is delivered up to the client application, the string will be automatically
       
  4229 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.  Note
       
  4230 ** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
       
  4231 ** since virtual tables are commonly implemented in loadable extensions which
       
  4232 ** do not have access to sqlite3MPrintf() or sqlite3Free().
       
  4233 **
       
  4234 ** This interface is experimental and is subject to change or
       
  4235 ** removal in future releases of SQLite.
       
  4236 */
       
  4237 struct sqlite3_vtab {
       
  4238   const sqlite3_module *pModule;  /* The module for this virtual table */
       
  4239   int nRef;                       /* Used internally */
       
  4240   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
       
  4241   /* Virtual table implementations will typically add additional fields */
       
  4242 };
       
  4243 
       
  4244 /*
       
  4245 ** CAPI3REF: Virtual Table Cursor Object  {H18020} <S20400>
       
  4246 ** KEYWORDS: sqlite3_vtab_cursor
       
  4247 ** EXPERIMENTAL
       
  4248 **
       
  4249 ** Every module implementation uses a subclass of the following structure
       
  4250 ** to describe cursors that point into the virtual table and are used
       
  4251 ** to loop through the virtual table.  Cursors are created using the
       
  4252 ** xOpen method of the module.  Each module implementation will define
       
  4253 ** the content of a cursor structure to suit its own needs.
       
  4254 **
       
  4255 ** This superclass exists in order to define fields of the cursor that
       
  4256 ** are common to all implementations.
       
  4257 **
       
  4258 ** This interface is experimental and is subject to change or
       
  4259 ** removal in future releases of SQLite.
       
  4260 */
       
  4261 struct sqlite3_vtab_cursor {
       
  4262   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
       
  4263   /* Virtual table implementations will typically add additional fields */
       
  4264 };
       
  4265 
       
  4266 /*
       
  4267 ** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400>
       
  4268 ** EXPERIMENTAL
       
  4269 **
       
  4270 ** The xCreate and xConnect methods of a module use the following API
       
  4271 ** to declare the format (the names and datatypes of the columns) of
       
  4272 ** the virtual tables they implement.
       
  4273 **
       
  4274 ** This interface is experimental and is subject to change or
       
  4275 ** removal in future releases of SQLite.
       
  4276 */
       
  4277 SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
       
  4278 
       
  4279 /*
       
  4280 ** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400>
       
  4281 ** EXPERIMENTAL
       
  4282 **
       
  4283 ** Virtual tables can provide alternative implementations of functions
       
  4284 ** using the xFindFunction method.  But global versions of those functions
       
  4285 ** must exist in order to be overloaded.
       
  4286 **
       
  4287 ** This API makes sure a global version of a function with a particular
       
  4288 ** name and number of parameters exists.  If no such function exists
       
  4289 ** before this API is called, a new function is created.  The implementation
       
  4290 ** of the new function always causes an exception to be thrown.  So
       
  4291 ** the new function is not good for anything by itself.  Its only
       
  4292 ** purpose is to be a placeholder function that can be overloaded
       
  4293 ** by virtual tables.
       
  4294 **
       
  4295 ** This API should be considered part of the virtual table interface,
       
  4296 ** which is experimental and subject to change.
       
  4297 */
       
  4298 SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
       
  4299 
       
  4300 /*
       
  4301 ** The interface to the virtual-table mechanism defined above (back up
       
  4302 ** to a comment remarkably similar to this one) is currently considered
       
  4303 ** to be experimental.  The interface might change in incompatible ways.
       
  4304 ** If this is a problem for you, do not use the interface at this time.
       
  4305 **
       
  4306 ** When the virtual-table mechanism stabilizes, we will declare the
       
  4307 ** interface fixed, support it indefinitely, and remove this comment.
       
  4308 **
       
  4309 ****** EXPERIMENTAL - subject to change without notice **************
       
  4310 */
       
  4311 
       
  4312 /*
       
  4313 ** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230>
       
  4314 ** KEYWORDS: {BLOB handle} {BLOB handles}
       
  4315 **
       
  4316 ** An instance of this object represents an open BLOB on which
       
  4317 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
       
  4318 ** Objects of this type are created by [sqlite3_blob_open()]
       
  4319 ** and destroyed by [sqlite3_blob_close()].
       
  4320 ** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
       
  4321 ** can be used to read or write small subsections of the BLOB.
       
  4322 ** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
       
  4323 */
       
  4324 typedef struct sqlite3_blob sqlite3_blob;
       
  4325 
       
  4326 /*
       
  4327 ** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230>
       
  4328 **
       
  4329 ** This interfaces opens a [BLOB handle | handle] to the BLOB located
       
  4330 ** in row iRow, column zColumn, table zTable in database zDb;
       
  4331 ** in other words, the same BLOB that would be selected by:
       
  4332 **
       
  4333 ** <pre>
       
  4334 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
       
  4335 ** </pre> {END}
       
  4336 **
       
  4337 ** If the flags parameter is non-zero, the the BLOB is opened for read
       
  4338 ** and write access. If it is zero, the BLOB is opened for read access.
       
  4339 **
       
  4340 ** Note that the database name is not the filename that contains
       
  4341 ** the database but rather the symbolic name of the database that
       
  4342 ** is assigned when the database is connected using [ATTACH].
       
  4343 ** For the main database file, the database name is "main".
       
  4344 ** For TEMP tables, the database name is "temp".
       
  4345 **
       
  4346 ** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written
       
  4347 ** to *ppBlob. Otherwise an [error code] is returned and any value written
       
  4348 ** to *ppBlob should not be used by the caller.
       
  4349 ** This function sets the [database connection] error code and message
       
  4350 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()].
       
  4351 **
       
  4352 ** If the row that a BLOB handle points to is modified by an
       
  4353 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
       
  4354 ** then the BLOB handle is marked as "expired".
       
  4355 ** This is true if any column of the row is changed, even a column
       
  4356 ** other than the one the BLOB handle is open on.
       
  4357 ** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
       
  4358 ** a expired BLOB handle fail with an return code of [SQLITE_ABORT].
       
  4359 ** Changes written into a BLOB prior to the BLOB expiring are not
       
  4360 ** rollback by the expiration of the BLOB.  Such changes will eventually
       
  4361 ** commit if the transaction continues to completion.
       
  4362 **
       
  4363 ** Requirements:
       
  4364 ** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824]
       
  4365 */
       
  4366 int sqlite3_blob_open(
       
  4367   sqlite3*,
       
  4368   const char *zDb,
       
  4369   const char *zTable,
       
  4370   const char *zColumn,
       
  4371   sqlite3_int64 iRow,
       
  4372   int flags,
       
  4373   sqlite3_blob **ppBlob
       
  4374 );
       
  4375 
       
  4376 /*
       
  4377 ** CAPI3REF: Close A BLOB Handle {H17830} <S30230>
       
  4378 **
       
  4379 ** Closes an open [BLOB handle].
       
  4380 **
       
  4381 ** Closing a BLOB shall cause the current transaction to commit
       
  4382 ** if there are no other BLOBs, no pending prepared statements, and the
       
  4383 ** database connection is in [autocommit mode].
       
  4384 ** If any writes were made to the BLOB, they might be held in cache
       
  4385 ** until the close operation if they will fit. {END}
       
  4386 **
       
  4387 ** Closing the BLOB often forces the changes
       
  4388 ** out to disk and so if any I/O errors occur, they will likely occur
       
  4389 ** at the time when the BLOB is closed.  {H17833} Any errors that occur during
       
  4390 ** closing are reported as a non-zero return value.
       
  4391 **
       
  4392 ** The BLOB is closed unconditionally.  Even if this routine returns
       
  4393 ** an error code, the BLOB is still closed.
       
  4394 **
       
  4395 ** Requirements:
       
  4396 ** [H17833] [H17836] [H17839]
       
  4397 */
       
  4398 int sqlite3_blob_close(sqlite3_blob *);
       
  4399 
       
  4400 /*
       
  4401 ** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230>
       
  4402 **
       
  4403 ** Returns the size in bytes of the BLOB accessible via the open
       
  4404 ** []BLOB handle] in its only argument.
       
  4405 **
       
  4406 ** Requirements:
       
  4407 ** [H17843]
       
  4408 */
       
  4409 int sqlite3_blob_bytes(sqlite3_blob *);
       
  4410 
       
  4411 /*
       
  4412 ** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230>
       
  4413 **
       
  4414 ** This function is used to read data from an open [BLOB handle] into a
       
  4415 ** caller-supplied buffer. N bytes of data are copied into buffer Z
       
  4416 ** from the open BLOB, starting at offset iOffset.
       
  4417 **
       
  4418 ** If offset iOffset is less than N bytes from the end of the BLOB,
       
  4419 ** [SQLITE_ERROR] is returned and no data is read.  If N or iOffset is
       
  4420 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
       
  4421 **
       
  4422 ** An attempt to read from an expired [BLOB handle] fails with an
       
  4423 ** error code of [SQLITE_ABORT].
       
  4424 **
       
  4425 ** On success, SQLITE_OK is returned.
       
  4426 ** Otherwise, an [error code] or an [extended error code] is returned.
       
  4427 **
       
  4428 ** Requirements:
       
  4429 ** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868]
       
  4430 */
       
  4431 int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
       
  4432 
       
  4433 /*
       
  4434 ** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230>
       
  4435 **
       
  4436 ** This function is used to write data into an open [BLOB handle] from a
       
  4437 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
       
  4438 ** into the open BLOB, starting at offset iOffset.
       
  4439 **
       
  4440 ** If the [BLOB handle] passed as the first argument was not opened for
       
  4441 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
       
  4442 ** this function returns [SQLITE_READONLY].
       
  4443 **
       
  4444 ** This function may only modify the contents of the BLOB; it is
       
  4445 ** not possible to increase the size of a BLOB using this API.
       
  4446 ** If offset iOffset is less than N bytes from the end of the BLOB,
       
  4447 ** [SQLITE_ERROR] is returned and no data is written.  If N is
       
  4448 ** less than zero [SQLITE_ERROR] is returned and no data is written.
       
  4449 **
       
  4450 ** An attempt to write to an expired [BLOB handle] fails with an
       
  4451 ** error code of [SQLITE_ABORT].  Writes to the BLOB that occurred
       
  4452 ** before the [BLOB handle] expired are not rolled back by the
       
  4453 ** expiration of the handle, though of course those changes might
       
  4454 ** have been overwritten by the statement that expired the BLOB handle
       
  4455 ** or by other independent statements.
       
  4456 **
       
  4457 ** On success, SQLITE_OK is returned.
       
  4458 ** Otherwise, an  [error code] or an [extended error code] is returned.
       
  4459 **
       
  4460 ** Requirements:
       
  4461 ** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885]
       
  4462 ** [H17888]
       
  4463 */
       
  4464 int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
       
  4465 
       
  4466 /*
       
  4467 ** CAPI3REF: Virtual File System Objects {H11200} <S20100>
       
  4468 **
       
  4469 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
       
  4470 ** that SQLite uses to interact
       
  4471 ** with the underlying operating system.  Most SQLite builds come with a
       
  4472 ** single default VFS that is appropriate for the host computer.
       
  4473 ** New VFSes can be registered and existing VFSes can be unregistered.
       
  4474 ** The following interfaces are provided.
       
  4475 **
       
  4476 ** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
       
  4477 ** Names are case sensitive.
       
  4478 ** Names are zero-terminated UTF-8 strings.
       
  4479 ** If there is no match, a NULL pointer is returned.
       
  4480 ** If zVfsName is NULL then the default VFS is returned.
       
  4481 **
       
  4482 ** New VFSes are registered with sqlite3_vfs_register().
       
  4483 ** Each new VFS becomes the default VFS if the makeDflt flag is set.
       
  4484 ** The same VFS can be registered multiple times without injury.
       
  4485 ** To make an existing VFS into the default VFS, register it again
       
  4486 ** with the makeDflt flag set.  If two different VFSes with the
       
  4487 ** same name are registered, the behavior is undefined.  If a
       
  4488 ** VFS is registered with a name that is NULL or an empty string,
       
  4489 ** then the behavior is undefined.
       
  4490 **
       
  4491 ** Unregister a VFS with the sqlite3_vfs_unregister() interface.
       
  4492 ** If the default VFS is unregistered, another VFS is chosen as
       
  4493 ** the default.  The choice for the new VFS is arbitrary.
       
  4494 **
       
  4495 ** Requirements:
       
  4496 ** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218]
       
  4497 */
       
  4498 sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
       
  4499 int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
       
  4500 int sqlite3_vfs_unregister(sqlite3_vfs*);
       
  4501 
       
  4502 /*
       
  4503 ** CAPI3REF: Mutexes {H17000} <S20000>
       
  4504 **
       
  4505 ** The SQLite core uses these routines for thread
       
  4506 ** synchronization. Though they are intended for internal
       
  4507 ** use by SQLite, code that links against SQLite is
       
  4508 ** permitted to use any of these routines.
       
  4509 **
       
  4510 ** The SQLite source code contains multiple implementations
       
  4511 ** of these mutex routines.  An appropriate implementation
       
  4512 ** is selected automatically at compile-time.  The following
       
  4513 ** implementations are available in the SQLite core:
       
  4514 **
       
  4515 ** <ul>
       
  4516 ** <li>   SQLITE_MUTEX_OS2
       
  4517 ** <li>   SQLITE_MUTEX_PTHREAD
       
  4518 ** <li>   SQLITE_MUTEX_W32
       
  4519 ** <li>   SQLITE_MUTEX_NOOP
       
  4520 ** </ul>
       
  4521 **
       
  4522 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
       
  4523 ** that does no real locking and is appropriate for use in
       
  4524 ** a single-threaded application.  The SQLITE_MUTEX_OS2,
       
  4525 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
       
  4526 ** are appropriate for use on OS/2, Unix, and Windows.
       
  4527 **
       
  4528 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
       
  4529 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
       
  4530 ** implementation is included with the library. In this case the
       
  4531 ** application must supply a custom mutex implementation using the
       
  4532 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
       
  4533 ** before calling sqlite3_initialize() or any other public sqlite3_
       
  4534 ** function that calls sqlite3_initialize().
       
  4535 **
       
  4536 ** {H17011} The sqlite3_mutex_alloc() routine allocates a new
       
  4537 ** mutex and returns a pointer to it. {H17012} If it returns NULL
       
  4538 ** that means that a mutex could not be allocated. {H17013} SQLite
       
  4539 ** will unwind its stack and return an error. {H17014} The argument
       
  4540 ** to sqlite3_mutex_alloc() is one of these integer constants:
       
  4541 **
       
  4542 ** <ul>
       
  4543 ** <li>  SQLITE_MUTEX_FAST
       
  4544 ** <li>  SQLITE_MUTEX_RECURSIVE
       
  4545 ** <li>  SQLITE_MUTEX_STATIC_MASTER
       
  4546 ** <li>  SQLITE_MUTEX_STATIC_MEM
       
  4547 ** <li>  SQLITE_MUTEX_STATIC_MEM2
       
  4548 ** <li>  SQLITE_MUTEX_STATIC_PRNG
       
  4549 ** <li>  SQLITE_MUTEX_STATIC_LRU
       
  4550 ** <li>  SQLITE_MUTEX_STATIC_LRU2
       
  4551 ** </ul>
       
  4552 **
       
  4553 ** {H17015} The first two constants cause sqlite3_mutex_alloc() to create
       
  4554 ** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
       
  4555 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
       
  4556 ** The mutex implementation does not need to make a distinction
       
  4557 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
       
  4558 ** not want to.  {H17016} But SQLite will only request a recursive mutex in
       
  4559 ** cases where it really needs one.  {END} If a faster non-recursive mutex
       
  4560 ** implementation is available on the host platform, the mutex subsystem
       
  4561 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
       
  4562 **
       
  4563 ** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return
       
  4564 ** a pointer to a static preexisting mutex. {END}  Four static mutexes are
       
  4565 ** used by the current version of SQLite.  Future versions of SQLite
       
  4566 ** may add additional static mutexes.  Static mutexes are for internal
       
  4567 ** use by SQLite only.  Applications that use SQLite mutexes should
       
  4568 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
       
  4569 ** SQLITE_MUTEX_RECURSIVE.
       
  4570 **
       
  4571 ** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
       
  4572 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
       
  4573 ** returns a different mutex on every call.  {H17034} But for the static
       
  4574 ** mutex types, the same mutex is returned on every call that has
       
  4575 ** the same type number.
       
  4576 **
       
  4577 ** {H17019} The sqlite3_mutex_free() routine deallocates a previously
       
  4578 ** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every
       
  4579 ** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in
       
  4580 ** use when they are deallocated. {A17022} Attempting to deallocate a static
       
  4581 ** mutex results in undefined behavior. {H17023} SQLite never deallocates
       
  4582 ** a static mutex. {END}
       
  4583 **
       
  4584 ** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
       
  4585 ** to enter a mutex. {H17024} If another thread is already within the mutex,
       
  4586 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
       
  4587 ** SQLITE_BUSY. {H17025}  The sqlite3_mutex_try() interface returns [SQLITE_OK]
       
  4588 ** upon successful entry.  {H17026} Mutexes created using
       
  4589 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
       
  4590 ** {H17027} In such cases the,
       
  4591 ** mutex must be exited an equal number of times before another thread
       
  4592 ** can enter.  {A17028} If the same thread tries to enter any other
       
  4593 ** kind of mutex more than once, the behavior is undefined.
       
  4594 ** {H17029} SQLite will never exhibit
       
  4595 ** such behavior in its own use of mutexes.
       
  4596 **
       
  4597 ** Some systems (for example, Windows 95) do not support the operation
       
  4598 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
       
  4599 ** will always return SQLITE_BUSY.  {H17030} The SQLite core only ever uses
       
  4600 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.
       
  4601 **
       
  4602 ** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was
       
  4603 ** previously entered by the same thread.  {A17032} The behavior
       
  4604 ** is undefined if the mutex is not currently entered by the
       
  4605 ** calling thread or is not currently allocated.  {H17033} SQLite will
       
  4606 ** never do either. {END}
       
  4607 **
       
  4608 ** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
       
  4609 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
       
  4610 ** behave as no-ops.
       
  4611 **
       
  4612 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
       
  4613 */
       
  4614 sqlite3_mutex *sqlite3_mutex_alloc(int);
       
  4615 void sqlite3_mutex_free(sqlite3_mutex*);
       
  4616 void sqlite3_mutex_enter(sqlite3_mutex*);
       
  4617 int sqlite3_mutex_try(sqlite3_mutex*);
       
  4618 void sqlite3_mutex_leave(sqlite3_mutex*);
       
  4619 
       
  4620 /*
       
  4621 ** CAPI3REF: Mutex Methods Object {H17120} <S20130>
       
  4622 ** EXPERIMENTAL
       
  4623 **
       
  4624 ** An instance of this structure defines the low-level routines
       
  4625 ** used to allocate and use mutexes.
       
  4626 **
       
  4627 ** Usually, the default mutex implementations provided by SQLite are
       
  4628 ** sufficient, however the user has the option of substituting a custom
       
  4629 ** implementation for specialized deployments or systems for which SQLite
       
  4630 ** does not provide a suitable implementation. In this case, the user
       
  4631 ** creates and populates an instance of this structure to pass
       
  4632 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
       
  4633 ** Additionally, an instance of this structure can be used as an
       
  4634 ** output variable when querying the system for the current mutex
       
  4635 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
       
  4636 **
       
  4637 ** The xMutexInit method defined by this structure is invoked as
       
  4638 ** part of system initialization by the sqlite3_initialize() function.
       
  4639 ** {H17001} The xMutexInit routine shall be called by SQLite once for each
       
  4640 ** effective call to [sqlite3_initialize()].
       
  4641 **
       
  4642 ** The xMutexEnd method defined by this structure is invoked as
       
  4643 ** part of system shutdown by the sqlite3_shutdown() function. The
       
  4644 ** implementation of this method is expected to release all outstanding
       
  4645 ** resources obtained by the mutex methods implementation, especially
       
  4646 ** those obtained by the xMutexInit method. {H17003} The xMutexEnd()
       
  4647 ** interface shall be invoked once for each call to [sqlite3_shutdown()].
       
  4648 **
       
  4649 ** The remaining seven methods defined by this structure (xMutexAlloc,
       
  4650 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
       
  4651 ** xMutexNotheld) implement the following interfaces (respectively):
       
  4652 **
       
  4653 ** <ul>
       
  4654 **   <li>  [sqlite3_mutex_alloc()] </li>
       
  4655 **   <li>  [sqlite3_mutex_free()] </li>
       
  4656 **   <li>  [sqlite3_mutex_enter()] </li>
       
  4657 **   <li>  [sqlite3_mutex_try()] </li>
       
  4658 **   <li>  [sqlite3_mutex_leave()] </li>
       
  4659 **   <li>  [sqlite3_mutex_held()] </li>
       
  4660 **   <li>  [sqlite3_mutex_notheld()] </li>
       
  4661 ** </ul>
       
  4662 **
       
  4663 ** The only difference is that the public sqlite3_XXX functions enumerated
       
  4664 ** above silently ignore any invocations that pass a NULL pointer instead
       
  4665 ** of a valid mutex handle. The implementations of the methods defined
       
  4666 ** by this structure are not required to handle this case, the results
       
  4667 ** of passing a NULL pointer instead of a valid mutex handle are undefined
       
  4668 ** (i.e. it is acceptable to provide an implementation that segfaults if
       
  4669 ** it is passed a NULL pointer).
       
  4670 */
       
  4671 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
       
  4672 struct sqlite3_mutex_methods {
       
  4673   int (*xMutexInit)(void);
       
  4674   int (*xMutexEnd)(void);
       
  4675   sqlite3_mutex *(*xMutexAlloc)(int);
       
  4676   void (*xMutexFree)(sqlite3_mutex *);
       
  4677   void (*xMutexEnter)(sqlite3_mutex *);
       
  4678   int (*xMutexTry)(sqlite3_mutex *);
       
  4679   void (*xMutexLeave)(sqlite3_mutex *);
       
  4680   int (*xMutexHeld)(sqlite3_mutex *);
       
  4681   int (*xMutexNotheld)(sqlite3_mutex *);
       
  4682 };
       
  4683 
       
  4684 /*
       
  4685 ** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800>
       
  4686 **
       
  4687 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
       
  4688 ** are intended for use inside assert() statements. {H17081} The SQLite core
       
  4689 ** never uses these routines except inside an assert() and applications
       
  4690 ** are advised to follow the lead of the core.  {H17082} The core only
       
  4691 ** provides implementations for these routines when it is compiled
       
  4692 ** with the SQLITE_DEBUG flag.  {A17087} External mutex implementations
       
  4693 ** are only required to provide these routines if SQLITE_DEBUG is
       
  4694 ** defined and if NDEBUG is not defined.
       
  4695 **
       
  4696 ** {H17083} These routines should return true if the mutex in their argument
       
  4697 ** is held or not held, respectively, by the calling thread.
       
  4698 **
       
  4699 ** {X17084} The implementation is not required to provided versions of these
       
  4700 ** routines that actually work. If the implementation does not provide working
       
  4701 ** versions of these routines, it should at least provide stubs that always
       
  4702 ** return true so that one does not get spurious assertion failures.
       
  4703 **
       
  4704 ** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then
       
  4705 ** the routine should return 1.  {END} This seems counter-intuitive since
       
  4706 ** clearly the mutex cannot be held if it does not exist.  But the
       
  4707 ** the reason the mutex does not exist is because the build is not
       
  4708 ** using mutexes.  And we do not want the assert() containing the
       
  4709 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
       
  4710 ** the appropriate thing to do.  {H17086} The sqlite3_mutex_notheld()
       
  4711 ** interface should also return 1 when given a NULL pointer.
       
  4712 */
       
  4713 int sqlite3_mutex_held(sqlite3_mutex*);
       
  4714 int sqlite3_mutex_notheld(sqlite3_mutex*);
       
  4715 
       
  4716 /*
       
  4717 ** CAPI3REF: Mutex Types {H17001} <H17000>
       
  4718 **
       
  4719 ** The [sqlite3_mutex_alloc()] interface takes a single argument
       
  4720 ** which is one of these integer constants.
       
  4721 **
       
  4722 ** The set of static mutexes may change from one SQLite release to the
       
  4723 ** next.  Applications that override the built-in mutex logic must be
       
  4724 ** prepared to accommodate additional static mutexes.
       
  4725 */
       
  4726 #define SQLITE_MUTEX_FAST             0
       
  4727 #define SQLITE_MUTEX_RECURSIVE        1
       
  4728 #define SQLITE_MUTEX_STATIC_MASTER    2
       
  4729 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
       
  4730 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
       
  4731 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
       
  4732 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
       
  4733 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
       
  4734 #define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */
       
  4735 
       
  4736 /*
       
  4737 ** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000>
       
  4738 **
       
  4739 ** This interface returns a pointer the [sqlite3_mutex] object that 
       
  4740 ** serializes access to the [database connection] given in the argument
       
  4741 ** when the [threading mode] is Serialized.
       
  4742 ** If the [threading mode] is Single-thread or Multi-thread then this
       
  4743 ** routine returns a NULL pointer.
       
  4744 */
       
  4745 sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
       
  4746 
       
  4747 /*
       
  4748 ** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800>
       
  4749 **
       
  4750 ** {H11301} The [sqlite3_file_control()] interface makes a direct call to the
       
  4751 ** xFileControl method for the [sqlite3_io_methods] object associated
       
  4752 ** with a particular database identified by the second argument. {H11302} The
       
  4753 ** name of the database is the name assigned to the database by the
       
  4754 ** <a href="lang_attach.html">ATTACH</a> SQL command that opened the
       
  4755 ** database. {H11303} To control the main database file, use the name "main"
       
  4756 ** or a NULL pointer. {H11304} The third and fourth parameters to this routine
       
  4757 ** are passed directly through to the second and third parameters of
       
  4758 ** the xFileControl method.  {H11305} The return value of the xFileControl
       
  4759 ** method becomes the return value of this routine.
       
  4760 **
       
  4761 ** {H11306} If the second parameter (zDbName) does not match the name of any
       
  4762 ** open database file, then SQLITE_ERROR is returned. {H11307} This error
       
  4763 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
       
  4764 ** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might
       
  4765 ** also return SQLITE_ERROR.  {A11309} There is no way to distinguish between
       
  4766 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
       
  4767 ** xFileControl method. {END}
       
  4768 **
       
  4769 ** See also: [SQLITE_FCNTL_LOCKSTATE]
       
  4770 */
       
  4771 int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
       
  4772 
       
  4773 /*
       
  4774 ** CAPI3REF: Testing Interface {H11400} <S30800>
       
  4775 **
       
  4776 ** The sqlite3_test_control() interface is used to read out internal
       
  4777 ** state of SQLite and to inject faults into SQLite for testing
       
  4778 ** purposes.  The first parameter is an operation code that determines
       
  4779 ** the number, meaning, and operation of all subsequent parameters.
       
  4780 **
       
  4781 ** This interface is not for use by applications.  It exists solely
       
  4782 ** for verifying the correct operation of the SQLite library.  Depending
       
  4783 ** on how the SQLite library is compiled, this interface might not exist.
       
  4784 **
       
  4785 ** The details of the operation codes, their meanings, the parameters
       
  4786 ** they take, and what they do are all subject to change without notice.
       
  4787 ** Unlike most of the SQLite API, this function is not guaranteed to
       
  4788 ** operate consistently from one release to the next.
       
  4789 */
       
  4790 int sqlite3_test_control(int op, ...);
       
  4791 
       
  4792 /*
       
  4793 ** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400>
       
  4794 **
       
  4795 ** These constants are the valid operation code parameters used
       
  4796 ** as the first argument to [sqlite3_test_control()].
       
  4797 **
       
  4798 ** These parameters and their meanings are subject to change
       
  4799 ** without notice.  These values are for testing purposes only.
       
  4800 ** Applications should not use any of these parameters or the
       
  4801 ** [sqlite3_test_control()] interface.
       
  4802 */
       
  4803 #define SQLITE_TESTCTRL_PRNG_SAVE                5
       
  4804 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
       
  4805 #define SQLITE_TESTCTRL_PRNG_RESET               7
       
  4806 #define SQLITE_TESTCTRL_BITVEC_TEST              8
       
  4807 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
       
  4808 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
       
  4809 #define SQLITE_TESTCTRL_PENDING_BYTE            11
       
  4810 
       
  4811 /*
       
  4812 ** CAPI3REF: SQLite Runtime Status {H17200} <S60200>
       
  4813 ** EXPERIMENTAL
       
  4814 **
       
  4815 ** This interface is used to retrieve runtime status information
       
  4816 ** about the preformance of SQLite, and optionally to reset various
       
  4817 ** highwater marks.  The first argument is an integer code for
       
  4818 ** the specific parameter to measure.  Recognized integer codes
       
  4819 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].
       
  4820 ** The current value of the parameter is returned into *pCurrent.
       
  4821 ** The highest recorded value is returned in *pHighwater.  If the
       
  4822 ** resetFlag is true, then the highest record value is reset after
       
  4823 ** *pHighwater is written. Some parameters do not record the highest
       
  4824 ** value.  For those parameters
       
  4825 ** nothing is written into *pHighwater and the resetFlag is ignored.
       
  4826 ** Other parameters record only the highwater mark and not the current
       
  4827 ** value.  For these latter parameters nothing is written into *pCurrent.
       
  4828 **
       
  4829 ** This routine returns SQLITE_OK on success and a non-zero
       
  4830 ** [error code] on failure.
       
  4831 **
       
  4832 ** This routine is threadsafe but is not atomic.  This routine can
       
  4833 ** called while other threads are running the same or different SQLite
       
  4834 ** interfaces.  However the values returned in *pCurrent and
       
  4835 ** *pHighwater reflect the status of SQLite at different points in time
       
  4836 ** and it is possible that another thread might change the parameter
       
  4837 ** in between the times when *pCurrent and *pHighwater are written.
       
  4838 **
       
  4839 ** See also: [sqlite3_db_status()]
       
  4840 */
       
  4841 SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
       
  4842 
       
  4843 
       
  4844 /*
       
  4845 ** CAPI3REF: Status Parameters {H17250} <H17200>
       
  4846 ** EXPERIMENTAL
       
  4847 **
       
  4848 ** These integer constants designate various run-time status parameters
       
  4849 ** that can be returned by [sqlite3_status()].
       
  4850 **
       
  4851 ** <dl>
       
  4852 ** <dt>SQLITE_STATUS_MEMORY_USED</dt>
       
  4853 ** <dd>This parameter is the current amount of memory checked out
       
  4854 ** using [sqlite3_malloc()], either directly or indirectly.  The
       
  4855 ** figure includes calls made to [sqlite3_malloc()] by the application
       
  4856 ** and internal memory usage by the SQLite library.  Scratch memory
       
  4857 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
       
  4858 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
       
  4859 ** this parameter.  The amount returned is the sum of the allocation
       
  4860 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>
       
  4861 **
       
  4862 ** <dt>SQLITE_STATUS_MALLOC_SIZE</dt>
       
  4863 ** <dd>This parameter records the largest memory allocation request
       
  4864 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
       
  4865 ** internal equivalents).  Only the value returned in the
       
  4866 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  4867 ** The value written into the *pCurrent parameter is undefined.</dd>
       
  4868 **
       
  4869 ** <dt>SQLITE_STATUS_PAGECACHE_USED</dt>
       
  4870 ** <dd>This parameter returns the number of pages used out of the
       
  4871 ** [pagecache memory allocator] that was configured using 
       
  4872 ** [SQLITE_CONFIG_PAGECACHE].  The
       
  4873 ** value returned is in pages, not in bytes.</dd>
       
  4874 **
       
  4875 ** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
       
  4876 ** <dd>This parameter returns the number of bytes of page cache
       
  4877 ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE]
       
  4878 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
       
  4879 ** returned value includes allocations that overflowed because they
       
  4880 ** where too large (they were larger than the "sz" parameter to
       
  4881 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
       
  4882 ** no space was left in the page cache.</dd>
       
  4883 **
       
  4884 ** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
       
  4885 ** <dd>This parameter records the largest memory allocation request
       
  4886 ** handed to [pagecache memory allocator].  Only the value returned in the
       
  4887 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  4888 ** The value written into the *pCurrent parameter is undefined.</dd>
       
  4889 **
       
  4890 ** <dt>SQLITE_STATUS_SCRATCH_USED</dt>
       
  4891 ** <dd>This parameter returns the number of allocations used out of the
       
  4892 ** [scratch memory allocator] configured using
       
  4893 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
       
  4894 ** in bytes.  Since a single thread may only have one scratch allocation
       
  4895 ** outstanding at time, this parameter also reports the number of threads
       
  4896 ** using scratch memory at the same time.</dd>
       
  4897 **
       
  4898 ** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
       
  4899 ** <dd>This parameter returns the number of bytes of scratch memory
       
  4900 ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH]
       
  4901 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
       
  4902 ** returned include overflows because the requested allocation was too
       
  4903 ** larger (that is, because the requested allocation was larger than the
       
  4904 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
       
  4905 ** slots were available.
       
  4906 ** </dd>
       
  4907 **
       
  4908 ** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
       
  4909 ** <dd>This parameter records the largest memory allocation request
       
  4910 ** handed to [scratch memory allocator].  Only the value returned in the
       
  4911 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
       
  4912 ** The value written into the *pCurrent parameter is undefined.</dd>
       
  4913 **
       
  4914 ** <dt>SQLITE_STATUS_PARSER_STACK</dt>
       
  4915 ** <dd>This parameter records the deepest parser stack.  It is only
       
  4916 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>
       
  4917 ** </dl>
       
  4918 **
       
  4919 ** New status parameters may be added from time to time.
       
  4920 */
       
  4921 #define SQLITE_STATUS_MEMORY_USED          0
       
  4922 #define SQLITE_STATUS_PAGECACHE_USED       1
       
  4923 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
       
  4924 #define SQLITE_STATUS_SCRATCH_USED         3
       
  4925 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4
       
  4926 #define SQLITE_STATUS_MALLOC_SIZE          5
       
  4927 #define SQLITE_STATUS_PARSER_STACK         6
       
  4928 #define SQLITE_STATUS_PAGECACHE_SIZE       7
       
  4929 #define SQLITE_STATUS_SCRATCH_SIZE         8
       
  4930 
       
  4931 /*
       
  4932 ** CAPI3REF: Database Connection Status {H17500} <S60200>
       
  4933 ** EXPERIMENTAL
       
  4934 **
       
  4935 ** This interface is used to retrieve runtime status information 
       
  4936 ** about a single [database connection].  The first argument is the
       
  4937 ** database connection object to be interrogated.  The second argument
       
  4938 ** is the parameter to interrogate.  Currently, the only allowed value
       
  4939 ** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
       
  4940 ** Additional options will likely appear in future releases of SQLite.
       
  4941 **
       
  4942 ** The current value of the requested parameter is written into *pCur
       
  4943 ** and the highest instantaneous value is written into *pHiwtr.  If
       
  4944 ** the resetFlg is true, then the highest instantaneous value is
       
  4945 ** reset back down to the current value.
       
  4946 **
       
  4947 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
       
  4948 */
       
  4949 SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
       
  4950 
       
  4951 /*
       
  4952 ** CAPI3REF: Status Parameters for database connections {H17520} <H17500>
       
  4953 ** EXPERIMENTAL
       
  4954 **
       
  4955 ** Status verbs for [sqlite3_db_status()].
       
  4956 **
       
  4957 ** <dl>
       
  4958 ** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
       
  4959 ** <dd>This parameter returns the number of lookaside memory slots currently
       
  4960 ** checked out.</dd>
       
  4961 ** </dl>
       
  4962 */
       
  4963 #define SQLITE_DBSTATUS_LOOKASIDE_USED     0
       
  4964 
       
  4965 
       
  4966 /*
       
  4967 ** CAPI3REF: Prepared Statement Status {H17550} <S60200>
       
  4968 ** EXPERIMENTAL
       
  4969 **
       
  4970 ** Each prepared statement maintains various
       
  4971 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number
       
  4972 ** of times it has performed specific operations.  These counters can
       
  4973 ** be used to monitor the performance characteristics of the prepared
       
  4974 ** statements.  For example, if the number of table steps greatly exceeds
       
  4975 ** the number of table searches or result rows, that would tend to indicate
       
  4976 ** that the prepared statement is using a full table scan rather than
       
  4977 ** an index.  
       
  4978 **
       
  4979 ** This interface is used to retrieve and reset counter values from
       
  4980 ** a [prepared statement].  The first argument is the prepared statement
       
  4981 ** object to be interrogated.  The second argument
       
  4982 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter]
       
  4983 ** to be interrogated. 
       
  4984 ** The current value of the requested counter is returned.
       
  4985 ** If the resetFlg is true, then the counter is reset to zero after this
       
  4986 ** interface call returns.
       
  4987 **
       
  4988 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
       
  4989 */
       
  4990 SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
       
  4991 
       
  4992 /*
       
  4993 ** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550>
       
  4994 ** EXPERIMENTAL
       
  4995 **
       
  4996 ** These preprocessor macros define integer codes that name counter
       
  4997 ** values associated with the [sqlite3_stmt_status()] interface.
       
  4998 ** The meanings of the various counters are as follows:
       
  4999 **
       
  5000 ** <dl>
       
  5001 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
       
  5002 ** <dd>This is the number of times that SQLite has stepped forward in
       
  5003 ** a table as part of a full table scan.  Large numbers for this counter
       
  5004 ** may indicate opportunities for performance improvement through 
       
  5005 ** careful use of indices.</dd>
       
  5006 **
       
  5007 ** <dt>SQLITE_STMTSTATUS_SORT</dt>
       
  5008 ** <dd>This is the number of sort operations that have occurred.
       
  5009 ** A non-zero value in this counter may indicate an opportunity to
       
  5010 ** improvement performance through careful use of indices.</dd>
       
  5011 **
       
  5012 ** </dl>
       
  5013 */
       
  5014 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
       
  5015 #define SQLITE_STMTSTATUS_SORT              2
       
  5016 
       
  5017 /*
       
  5018 ** CAPI3REF: Custom Page Cache Object
       
  5019 ** EXPERIMENTAL
       
  5020 **
       
  5021 ** The sqlite3_pcache type is opaque.  It is implemented by
       
  5022 ** the pluggable module.  The SQLite core has no knowledge of
       
  5023 ** its size or internal structure and never deals with the
       
  5024 ** sqlite3_pcache object except by holding and passing pointers
       
  5025 ** to the object.
       
  5026 **
       
  5027 ** See [sqlite3_pcache_methods] for additional information.
       
  5028 */
       
  5029 typedef struct sqlite3_pcache sqlite3_pcache;
       
  5030 
       
  5031 /*
       
  5032 ** CAPI3REF: Application Defined Page Cache.
       
  5033 ** EXPERIMENTAL
       
  5034 **
       
  5035 ** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can
       
  5036 ** register an alternative page cache implementation by passing in an 
       
  5037 ** instance of the sqlite3_pcache_methods structure. The majority of the 
       
  5038 ** heap memory used by sqlite is used by the page cache to cache data read 
       
  5039 ** from, or ready to be written to, the database file. By implementing a 
       
  5040 ** custom page cache using this API, an application can control more 
       
  5041 ** precisely the amount of memory consumed by sqlite, the way in which 
       
  5042 ** said memory is allocated and released, and the policies used to 
       
  5043 ** determine exactly which parts of a database file are cached and for 
       
  5044 ** how long.
       
  5045 **
       
  5046 ** The contents of the structure are copied to an internal buffer by sqlite
       
  5047 ** within the call to [sqlite3_config].
       
  5048 **
       
  5049 ** The xInit() method is called once for each call to [sqlite3_initialize()]
       
  5050 ** (usually only once during the lifetime of the process). It is passed
       
  5051 ** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set
       
  5052 ** up global structures and mutexes required by the custom page cache 
       
  5053 ** implementation. The xShutdown() method is called from within 
       
  5054 ** [sqlite3_shutdown()], if the application invokes this API. It can be used
       
  5055 ** to clean up any outstanding resources before process shutdown, if required.
       
  5056 **
       
  5057 ** The xCreate() method is used to construct a new cache instance. The
       
  5058 ** first parameter, szPage, is the size in bytes of the pages that must
       
  5059 ** be allocated by the cache. szPage will not be a power of two. The
       
  5060 ** second argument, bPurgeable, is true if the cache being created will
       
  5061 ** be used to cache database pages read from a file stored on disk, or
       
  5062 ** false if it is used for an in-memory database. The cache implementation
       
  5063 ** does not have to do anything special based on the value of bPurgeable,
       
  5064 ** it is purely advisory. 
       
  5065 **
       
  5066 ** The xCachesize() method may be called at any time by SQLite to set the
       
  5067 ** suggested maximum cache-size (number of pages stored by) the cache
       
  5068 ** instance passed as the first argument. This is the value configured using
       
  5069 ** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter,
       
  5070 ** the implementation is not required to do anything special with this
       
  5071 ** value, it is advisory only.
       
  5072 **
       
  5073 ** The xPagecount() method should return the number of pages currently
       
  5074 ** stored in the cache supplied as an argument.
       
  5075 ** 
       
  5076 ** The xFetch() method is used to fetch a page and return a pointer to it. 
       
  5077 ** A 'page', in this context, is a buffer of szPage bytes aligned at an
       
  5078 ** 8-byte boundary. The page to be fetched is determined by the key. The
       
  5079 ** mimimum key value is 1. After it has been retrieved using xFetch, the page 
       
  5080 ** is considered to be pinned.
       
  5081 **
       
  5082 ** If the requested page is already in the page cache, then a pointer to
       
  5083 ** the cached buffer should be returned with its contents intact. If the
       
  5084 ** page is not already in the cache, then the expected behaviour of the
       
  5085 ** cache is determined by the value of the createFlag parameter passed
       
  5086 ** to xFetch, according to the following table:
       
  5087 **
       
  5088 ** <table border=1 width=85% align=center>
       
  5089 **   <tr><th>createFlag<th>Expected Behaviour
       
  5090 **   <tr><td>0<td>NULL should be returned. No new cache entry is created.
       
  5091 **   <tr><td>1<td>If createFlag is set to 1, this indicates that 
       
  5092 **                SQLite is holding pinned pages that can be unpinned
       
  5093 **                by writing their contents to the database file (a
       
  5094 **                relatively expensive operation). In this situation the
       
  5095 **                cache implementation has two choices: it can return NULL,
       
  5096 **                in which case SQLite will attempt to unpin one or more 
       
  5097 **                pages before re-requesting the same page, or it can
       
  5098 **                allocate a new page and return a pointer to it. If a new
       
  5099 **                page is allocated, then the first sizeof(void*) bytes of
       
  5100 **                it (at least) must be zeroed before it is returned.
       
  5101 **   <tr><td>2<td>If createFlag is set to 2, then SQLite is not holding any
       
  5102 **                pinned pages associated with the specific cache passed
       
  5103 **                as the first argument to xFetch() that can be unpinned. The
       
  5104 **                cache implementation should attempt to allocate a new
       
  5105 **                cache entry and return a pointer to it. Again, the first
       
  5106 **                sizeof(void*) bytes of the page should be zeroed before 
       
  5107 **                it is returned. If the xFetch() method returns NULL when 
       
  5108 **                createFlag==2, SQLite assumes that a memory allocation 
       
  5109 **                failed and returns SQLITE_NOMEM to the user.
       
  5110 ** </table>
       
  5111 **
       
  5112 ** xUnpin() is called by SQLite with a pointer to a currently pinned page
       
  5113 ** as its second argument. If the third parameter, discard, is non-zero,
       
  5114 ** then the page should be evicted from the cache. In this case SQLite 
       
  5115 ** assumes that the next time the page is retrieved from the cache using
       
  5116 ** the xFetch() method, it will be zeroed. If the discard parameter is
       
  5117 ** zero, then the page is considered to be unpinned. The cache implementation
       
  5118 ** may choose to reclaim (free or recycle) unpinned pages at any time.
       
  5119 ** SQLite assumes that next time the page is retrieved from the cache
       
  5120 ** it will either be zeroed, or contain the same data that it did when it
       
  5121 ** was unpinned.
       
  5122 **
       
  5123 ** The cache is not required to perform any reference counting. A single 
       
  5124 ** call to xUnpin() unpins the page regardless of the number of prior calls 
       
  5125 ** to xFetch().
       
  5126 **
       
  5127 ** The xRekey() method is used to change the key value associated with the
       
  5128 ** page passed as the second argument from oldKey to newKey. If the cache
       
  5129 ** previously contains an entry associated with newKey, it should be
       
  5130 ** discarded. Any prior cache entry associated with newKey is guaranteed not
       
  5131 ** to be pinned.
       
  5132 **
       
  5133 ** When SQLite calls the xTruncate() method, the cache must discard all
       
  5134 ** existing cache entries with page numbers (keys) greater than or equal
       
  5135 ** to the value of the iLimit parameter passed to xTruncate(). If any
       
  5136 ** of these pages are pinned, they are implicitly unpinned, meaning that
       
  5137 ** they can be safely discarded.
       
  5138 **
       
  5139 ** The xDestroy() method is used to delete a cache allocated by xCreate().
       
  5140 ** All resources associated with the specified cache should be freed. After
       
  5141 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
       
  5142 ** handle invalid, and will not use it with any other sqlite3_pcache_methods
       
  5143 ** functions.
       
  5144 */
       
  5145 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
       
  5146 struct sqlite3_pcache_methods {
       
  5147   void *pArg;
       
  5148   int (*xInit)(void*);
       
  5149   void (*xShutdown)(void*);
       
  5150   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
       
  5151   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
       
  5152   int (*xPagecount)(sqlite3_pcache*);
       
  5153   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
       
  5154   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
       
  5155   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
       
  5156   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
       
  5157   void (*xDestroy)(sqlite3_pcache*);
       
  5158 };
       
  5159 
       
  5160 /*
       
  5161 ** CAPI3REF: Online Backup Object
       
  5162 ** EXPERIMENTAL
       
  5163 **
       
  5164 ** The sqlite3_backup object records state information about an ongoing
       
  5165 ** online backup operation.  The sqlite3_backup object is created by
       
  5166 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
       
  5167 ** [sqlite3_backup_finish()].
       
  5168 **
       
  5169 ** See Also: [Using the SQLite Online Backup API]
       
  5170 */
       
  5171 typedef struct sqlite3_backup sqlite3_backup;
       
  5172 
       
  5173 /*
       
  5174 ** CAPI3REF: Online Backup API.
       
  5175 ** EXPERIMENTAL
       
  5176 **
       
  5177 ** This API is used to overwrite the contents of one database with that
       
  5178 ** of another. It is useful either for creating backups of databases or
       
  5179 ** for copying in-memory databases to or from persistent files. 
       
  5180 **
       
  5181 ** See Also: [Using the SQLite Online Backup API]
       
  5182 **
       
  5183 ** Exclusive access is required to the destination database for the 
       
  5184 ** duration of the operation. However the source database is only
       
  5185 ** read-locked while it is actually being read, it is not locked
       
  5186 ** continuously for the entire operation. Thus, the backup may be
       
  5187 ** performed on a live database without preventing other users from
       
  5188 ** writing to the database for an extended period of time.
       
  5189 ** 
       
  5190 ** To perform a backup operation: 
       
  5191 **   <ol>
       
  5192 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
       
  5193 **         backup, 
       
  5194 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
       
  5195 **         the data between the two databases, and finally
       
  5196 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
       
  5197 **         associated with the backup operation. 
       
  5198 **   </ol>
       
  5199 ** There should be exactly one call to sqlite3_backup_finish() for each
       
  5200 ** successful call to sqlite3_backup_init().
       
  5201 **
       
  5202 ** <b>sqlite3_backup_init()</b>
       
  5203 **
       
  5204 ** The first two arguments passed to [sqlite3_backup_init()] are the database
       
  5205 ** handle associated with the destination database and the database name 
       
  5206 ** used to attach the destination database to the handle. The database name
       
  5207 ** is "main" for the main database, "temp" for the temporary database, or
       
  5208 ** the name specified as part of the [ATTACH] statement if the destination is
       
  5209 ** an attached database. The third and fourth arguments passed to 
       
  5210 ** sqlite3_backup_init() identify the [database connection]
       
  5211 ** and database name used
       
  5212 ** to access the source database. The values passed for the source and 
       
  5213 ** destination [database connection] parameters must not be the same.
       
  5214 **
       
  5215 ** If an error occurs within sqlite3_backup_init(), then NULL is returned
       
  5216 ** and an error code and error message written into the [database connection] 
       
  5217 ** passed as the first argument. They may be retrieved using the
       
  5218 ** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions.
       
  5219 ** Otherwise, if successful, a pointer to an [sqlite3_backup] object is
       
  5220 ** returned. This pointer may be used with the sqlite3_backup_step() and
       
  5221 ** sqlite3_backup_finish() functions to perform the specified backup 
       
  5222 ** operation.
       
  5223 **
       
  5224 ** <b>sqlite3_backup_step()</b>
       
  5225 **
       
  5226 ** Function [sqlite3_backup_step()] is used to copy up to nPage pages between 
       
  5227 ** the source and destination databases, where nPage is the value of the 
       
  5228 ** second parameter passed to sqlite3_backup_step(). If nPage is a negative
       
  5229 ** value, all remaining source pages are copied. If the required pages are 
       
  5230 ** succesfully copied, but there are still more pages to copy before the 
       
  5231 ** backup is complete, it returns [SQLITE_OK]. If no error occured and there 
       
  5232 ** are no more pages to copy, then [SQLITE_DONE] is returned. If an error 
       
  5233 ** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and
       
  5234 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
       
  5235 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
       
  5236 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
       
  5237 **
       
  5238 ** As well as the case where the destination database file was opened for
       
  5239 ** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if
       
  5240 ** the destination is an in-memory database with a different page size
       
  5241 ** from the source database.
       
  5242 **
       
  5243 ** If sqlite3_backup_step() cannot obtain a required file-system lock, then
       
  5244 ** the [sqlite3_busy_handler | busy-handler function]
       
  5245 ** is invoked (if one is specified). If the 
       
  5246 ** busy-handler returns non-zero before the lock is available, then 
       
  5247 ** [SQLITE_BUSY] is returned to the caller. In this case the call to
       
  5248 ** sqlite3_backup_step() can be retried later. If the source
       
  5249 ** [database connection]
       
  5250 ** is being used to write to the source database when sqlite3_backup_step()
       
  5251 ** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this
       
  5252 ** case the call to sqlite3_backup_step() can be retried later on. If
       
  5253 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
       
  5254 ** [SQLITE_READONLY] is returned, then 
       
  5255 ** there is no point in retrying the call to sqlite3_backup_step(). These 
       
  5256 ** errors are considered fatal. At this point the application must accept 
       
  5257 ** that the backup operation has failed and pass the backup operation handle 
       
  5258 ** to the sqlite3_backup_finish() to release associated resources.
       
  5259 **
       
  5260 ** Following the first call to sqlite3_backup_step(), an exclusive lock is
       
  5261 ** obtained on the destination file. It is not released until either 
       
  5262 ** sqlite3_backup_finish() is called or the backup operation is complete 
       
  5263 ** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time 
       
  5264 ** a call to sqlite3_backup_step() is made a [shared lock] is obtained on
       
  5265 ** the source database file. This lock is released before the
       
  5266 ** sqlite3_backup_step() call returns. Because the source database is not
       
  5267 ** locked between calls to sqlite3_backup_step(), it may be modified mid-way
       
  5268 ** through the backup procedure. If the source database is modified by an
       
  5269 ** external process or via a database connection other than the one being
       
  5270 ** used by the backup operation, then the backup will be transparently
       
  5271 ** restarted by the next call to sqlite3_backup_step(). If the source 
       
  5272 ** database is modified by the using the same database connection as is used
       
  5273 ** by the backup operation, then the backup database is transparently 
       
  5274 ** updated at the same time.
       
  5275 **
       
  5276 ** <b>sqlite3_backup_finish()</b>
       
  5277 **
       
  5278 ** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
       
  5279 ** application wishes to abandon the backup operation, the [sqlite3_backup]
       
  5280 ** object should be passed to sqlite3_backup_finish(). This releases all
       
  5281 ** resources associated with the backup operation. If sqlite3_backup_step()
       
  5282 ** has not yet returned [SQLITE_DONE], then any active write-transaction on the
       
  5283 ** destination database is rolled back. The [sqlite3_backup] object is invalid
       
  5284 ** and may not be used following a call to sqlite3_backup_finish().
       
  5285 **
       
  5286 ** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error
       
  5287 ** occurred, regardless or whether or not sqlite3_backup_step() was called
       
  5288 ** a sufficient number of times to complete the backup operation. Or, if
       
  5289 ** an out-of-memory condition or IO error occured during a call to
       
  5290 ** sqlite3_backup_step() then [SQLITE_NOMEM] or an
       
  5291 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code
       
  5292 ** is returned. In this case the error code and an error message are
       
  5293 ** written to the destination [database connection].
       
  5294 **
       
  5295 ** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is
       
  5296 ** not a permanent error and does not affect the return value of
       
  5297 ** sqlite3_backup_finish().
       
  5298 **
       
  5299 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b>
       
  5300 **
       
  5301 ** Each call to sqlite3_backup_step() sets two values stored internally
       
  5302 ** by an [sqlite3_backup] object. The number of pages still to be backed
       
  5303 ** up, which may be queried by sqlite3_backup_remaining(), and the total
       
  5304 ** number of pages in the source database file, which may be queried by
       
  5305 ** sqlite3_backup_pagecount().
       
  5306 **
       
  5307 ** The values returned by these functions are only updated by
       
  5308 ** sqlite3_backup_step(). If the source database is modified during a backup
       
  5309 ** operation, then the values are not updated to account for any extra
       
  5310 ** pages that need to be updated or the size of the source database file
       
  5311 ** changing.
       
  5312 **
       
  5313 ** <b>Concurrent Usage of Database Handles</b>
       
  5314 **
       
  5315 ** The source [database connection] may be used by the application for other
       
  5316 ** purposes while a backup operation is underway or being initialized.
       
  5317 ** If SQLite is compiled and configured to support threadsafe database
       
  5318 ** connections, then the source database connection may be used concurrently
       
  5319 ** from within other threads.
       
  5320 **
       
  5321 ** However, the application must guarantee that the destination database
       
  5322 ** connection handle is not passed to any other API (by any thread) after 
       
  5323 ** sqlite3_backup_init() is called and before the corresponding call to
       
  5324 ** sqlite3_backup_finish(). Unfortunately SQLite does not currently check
       
  5325 ** for this, if the application does use the destination [database connection]
       
  5326 ** for some other purpose during a backup operation, things may appear to
       
  5327 ** work correctly but in fact be subtly malfunctioning.  Use of the
       
  5328 ** destination database connection while a backup is in progress might
       
  5329 ** also cause a mutex deadlock.
       
  5330 **
       
  5331 ** Furthermore, if running in [shared cache mode], the application must
       
  5332 ** guarantee that the shared cache used by the destination database
       
  5333 ** is not accessed while the backup is running. In practice this means
       
  5334 ** that the application must guarantee that the file-system file being 
       
  5335 ** backed up to is not accessed by any connection within the process,
       
  5336 ** not just the specific connection that was passed to sqlite3_backup_init().
       
  5337 **
       
  5338 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
       
  5339 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
       
  5340 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
       
  5341 ** APIs are not strictly speaking threadsafe. If they are invoked at the
       
  5342 ** same time as another thread is invoking sqlite3_backup_step() it is
       
  5343 ** possible that they return invalid values.
       
  5344 */
       
  5345 sqlite3_backup *sqlite3_backup_init(
       
  5346   sqlite3 *pDest,                        /* Destination database handle */
       
  5347   const char *zDestName,                 /* Destination database name */
       
  5348   sqlite3 *pSource,                      /* Source database handle */
       
  5349   const char *zSourceName                /* Source database name */
       
  5350 );
       
  5351 int sqlite3_backup_step(sqlite3_backup *p, int nPage);
       
  5352 int sqlite3_backup_finish(sqlite3_backup *p);
       
  5353 int sqlite3_backup_remaining(sqlite3_backup *p);
       
  5354 int sqlite3_backup_pagecount(sqlite3_backup *p);
       
  5355 
       
  5356 /*
       
  5357 ** CAPI3REF: Unlock Notification
       
  5358 ** EXPERIMENTAL
       
  5359 **
       
  5360 ** When running in shared-cache mode, a database operation may fail with
       
  5361 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
       
  5362 ** individual tables within the shared-cache cannot be obtained. See
       
  5363 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
       
  5364 ** This API may be used to register a callback that SQLite will invoke 
       
  5365 ** when the connection currently holding the required lock relinquishes it.
       
  5366 ** This API is only available if the library was compiled with the
       
  5367 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
       
  5368 **
       
  5369 ** See Also: [Using the SQLite Unlock Notification Feature].
       
  5370 **
       
  5371 ** Shared-cache locks are released when a database connection concludes
       
  5372 ** its current transaction, either by committing it or rolling it back. 
       
  5373 **
       
  5374 ** When a connection (known as the blocked connection) fails to obtain a
       
  5375 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
       
  5376 ** identity of the database connection (the blocking connection) that
       
  5377 ** has locked the required resource is stored internally. After an 
       
  5378 ** application receives an SQLITE_LOCKED error, it may call the
       
  5379 ** sqlite3_unlock_notify() method with the blocked connection handle as 
       
  5380 ** the first argument to register for a callback that will be invoked
       
  5381 ** when the blocking connections current transaction is concluded. The
       
  5382 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
       
  5383 ** call that concludes the blocking connections transaction.
       
  5384 **
       
  5385 ** If sqlite3_unlock_notify() is called in a multi-threaded application,
       
  5386 ** there is a chance that the blocking connection will have already
       
  5387 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
       
  5388 ** If this happens, then the specified callback is invoked immediately,
       
  5389 ** from within the call to sqlite3_unlock_notify().
       
  5390 **
       
  5391 ** If the blocked connection is attempting to obtain a write-lock on a
       
  5392 ** shared-cache table, and more than one other connection currently holds
       
  5393 ** a read-lock on the same table, then SQLite arbitrarily selects one of 
       
  5394 ** the other connections to use as the blocking connection.
       
  5395 **
       
  5396 ** There may be at most one unlock-notify callback registered by a 
       
  5397 ** blocked connection. If sqlite3_unlock_notify() is called when the
       
  5398 ** blocked connection already has a registered unlock-notify callback,
       
  5399 ** then the new callback replaces the old. If sqlite3_unlock_notify() is
       
  5400 ** called with a NULL pointer as its second argument, then any existing
       
  5401 ** unlock-notify callback is cancelled. The blocked connections 
       
  5402 ** unlock-notify callback may also be canceled by closing the blocked
       
  5403 ** connection using [sqlite3_close()].
       
  5404 **
       
  5405 ** The unlock-notify callback is not reentrant. If an application invokes
       
  5406 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
       
  5407 ** crash or deadlock may be the result.
       
  5408 **
       
  5409 ** Unless deadlock is detected (see below), sqlite3_unlock_notify() always
       
  5410 ** returns SQLITE_OK.
       
  5411 **
       
  5412 ** <b>Callback Invocation Details</b>
       
  5413 **
       
  5414 ** When an unlock-notify callback is registered, the application provides a 
       
  5415 ** single void* pointer that is passed to the callback when it is invoked.
       
  5416 ** However, the signature of the callback function allows SQLite to pass
       
  5417 ** it an array of void* context pointers. The first argument passed to
       
  5418 ** an unlock-notify callback is a pointer to an array of void* pointers,
       
  5419 ** and the second is the number of entries in the array.
       
  5420 **
       
  5421 ** When a blocking connections transaction is concluded, there may be
       
  5422 ** more than one blocked connection that has registered for an unlock-notify
       
  5423 ** callback. If two or more such blocked connections have specified the
       
  5424 ** same callback function, then instead of invoking the callback function
       
  5425 ** multiple times, it is invoked once with the set of void* context pointers
       
  5426 ** specified by the blocked connections bundled together into an array.
       
  5427 ** This gives the application an opportunity to prioritize any actions 
       
  5428 ** related to the set of unblocked database connections.
       
  5429 **
       
  5430 ** <b>Deadlock Detection</b>
       
  5431 **
       
  5432 ** Assuming that after registering for an unlock-notify callback a 
       
  5433 ** database waits for the callback to be issued before taking any further
       
  5434 ** action (a reasonable assumption), then using this API may cause the
       
  5435 ** application to deadlock. For example, if connection X is waiting for
       
  5436 ** connection Y's transaction to be concluded, and similarly connection
       
  5437 ** Y is waiting on connection X's transaction, then neither connection
       
  5438 ** will proceed and the system may remain deadlocked indefinitely.
       
  5439 **
       
  5440 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
       
  5441 ** detection. If a given call to sqlite3_unlock_notify() would put the
       
  5442 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
       
  5443 ** unlock-notify callback is registered. The system is said to be in
       
  5444 ** a deadlocked state if connection A has registered for an unlock-notify
       
  5445 ** callback on the conclusion of connection B's transaction, and connection
       
  5446 ** B has itself registered for an unlock-notify callback when connection
       
  5447 ** A's transaction is concluded. Indirect deadlock is also detected, so
       
  5448 ** the system is also considered to be deadlocked if connection B has
       
  5449 ** registered for an unlock-notify callback on the conclusion of connection
       
  5450 ** C's transaction, where connection C is waiting on connection A. Any
       
  5451 ** number of levels of indirection are allowed.
       
  5452 **
       
  5453 ** <b>The "DROP TABLE" Exception</b>
       
  5454 **
       
  5455 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
       
  5456 ** always appropriate to call sqlite3_unlock_notify(). There is however,
       
  5457 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
       
  5458 ** SQLite checks if there are any currently executing SELECT statements
       
  5459 ** that belong to the same connection. If there are, SQLITE_LOCKED is
       
  5460 ** returned. In this case there is no "blocking connection", so invoking
       
  5461 ** sqlite3_unlock_notify() results in the unlock-notify callback being
       
  5462 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
       
  5463 ** or "DROP INDEX" query, an infinite loop might be the result.
       
  5464 **
       
  5465 ** One way around this problem is to check the extended error code returned
       
  5466 ** by an sqlite3_step() call. If there is a blocking connection, then the
       
  5467 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
       
  5468 ** the special "DROP TABLE/INDEX" case, the extended error code is just 
       
  5469 ** SQLITE_LOCKED.
       
  5470 */
       
  5471 int sqlite3_unlock_notify(
       
  5472   sqlite3 *pBlocked,                          /* Waiting connection */
       
  5473   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
       
  5474   void *pNotifyArg                            /* Argument to pass to xNotify */
       
  5475 );
       
  5476 
       
  5477 /*
       
  5478 ** Undo the hack that converts floating point types to integer for
       
  5479 ** builds on processors without floating point support.
       
  5480 */
       
  5481 #ifdef SQLITE_OMIT_FLOATING_POINT
       
  5482 # undef double
       
  5483 #endif
       
  5484 
       
  5485 #ifdef __cplusplus
       
  5486 }  /* End of the 'extern "C"' block */
       
  5487 #endif
       
  5488 #endif