/*** 2007 August 28**** The author disclaims copyright to this source code. In place of** a legal notice, here is a blessing:**** May you do good and not evil.** May you find forgiveness for yourself and forgive others.** May you share freely, never taking more than you give.******************************************************************************* This file contains the common header for all mutex implementations.** The sqliteInt.h header #includes this file so that it is available** to all source files. We break it out in an effort to keep the code** better organized.**** NOTE: source files should *not* #include this header file directly.** Source files should #include the sqliteInt.h file and let that file** include this one indirectly.**** $Id: mutex.h,v 1.9 2008/10/07 15:25:48 drh Exp $*//*** Figure out what version of the code to use. The choices are**** SQLITE_MUTEX_OMIT No mutex logic. Not even stubs. The** mutexes implemention cannot be overridden** at start-time.**** SQLITE_MUTEX_NOOP For single-threaded applications. No** mutual exclusion is provided. But this** implementation can be overridden at** start-time.**** SQLITE_MUTEX_PTHREADS For multi-threaded applications on Unix.**** SQLITE_MUTEX_W32 For multi-threaded applications on Win32.**** SQLITE_MUTEX_OS2 For multi-threaded applications on OS/2.*/#if !SQLITE_THREADSAFE# define SQLITE_MUTEX_OMIT#endif#if SQLITE_THREADSAFE && !defined(SQLITE_MUTEX_NOOP)# if SQLITE_OS_UNIX# define SQLITE_MUTEX_PTHREADS# elif SQLITE_OS_WIN# define SQLITE_MUTEX_W32# elif SQLITE_OS_OS2# define SQLITE_MUTEX_OS2# else# define SQLITE_MUTEX_NOOP# endif#endif#ifdef SQLITE_MUTEX_OMIT/*** If this is a no-op implementation, implement everything as macros.*/#define sqlite3_mutex_alloc(X) ((sqlite3_mutex*)8)#define sqlite3_mutex_free(X)#define sqlite3_mutex_enter(X)#define sqlite3_mutex_try(X) SQLITE_OK#define sqlite3_mutex_leave(X)#define sqlite3_mutex_held(X) 1#define sqlite3_mutex_notheld(X) 1#define sqlite3MutexAlloc(X) ((sqlite3_mutex*)8)#define sqlite3MutexInit() SQLITE_OK#define sqlite3MutexEnd()#endif /* defined(SQLITE_OMIT_MUTEX) */