1/*
2** 2007 August 28
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**
13** This file contains the common header for all mutex implementations.
14** The sqliteInt.h header #includes this file so that it is available
15** to all source files.  We break it out in an effort to keep the code
16** better organized.
17**
18** NOTE:  source files should *not* #include this header file directly.
19** Source files should #include the sqliteInt.h file and let that file
20** include this one indirectly.
21*/
22
23
24/*
25** Figure out what version of the code to use.  The choices are
26**
27**   SQLITE_MUTEX_OMIT         No mutex logic.  Not even stubs.  The
28**                             mutexes implemention cannot be overridden
29**                             at start-time.
30**
31**   SQLITE_MUTEX_NOOP         For single-threaded applications.  No
32**                             mutual exclusion is provided.  But this
33**                             implementation can be overridden at
34**                             start-time.
35**
36**   SQLITE_MUTEX_PTHREADS     For multi-threaded applications on Unix.
37**
38**   SQLITE_MUTEX_W32          For multi-threaded applications on Win32.
39**
40**   SQLITE_MUTEX_OS2          For multi-threaded applications on OS/2.
41*/
42#if !SQLITE_THREADSAFE
43# define SQLITE_MUTEX_OMIT
44#endif
45#if SQLITE_THREADSAFE && !defined(SQLITE_MUTEX_NOOP)
46#  if SQLITE_OS_UNIX
47#    define SQLITE_MUTEX_PTHREADS
48#  elif SQLITE_OS_WIN
49#    define SQLITE_MUTEX_W32
50#  elif SQLITE_OS_OS2
51#    define SQLITE_MUTEX_OS2
52#  else
53#    define SQLITE_MUTEX_NOOP
54#  endif
55#endif
56
57#ifdef SQLITE_MUTEX_OMIT
58/*
59** If this is a no-op implementation, implement everything as macros.
60*/
61#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
62#define sqlite3_mutex_free(X)
63#define sqlite3_mutex_enter(X)
64#define sqlite3_mutex_try(X)      SQLITE_OK
65#define sqlite3_mutex_leave(X)
66#define sqlite3_mutex_held(X)     ((void)(X),1)
67#define sqlite3_mutex_notheld(X)  ((void)(X),1)
68#define sqlite3MutexAlloc(X)      ((sqlite3_mutex*)8)
69#define sqlite3MutexInit()        SQLITE_OK
70#define sqlite3MutexEnd()
71#endif /* defined(SQLITE_MUTEX_OMIT) */
72