diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/mutex_w32.c | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/src/mutex_w32.c b/src/mutex_w32.c index 0c2e08db1..ee5a4088d 100644 --- a/src/mutex_w32.c +++ b/src/mutex_w32.c @@ -11,7 +11,7 @@ ************************************************************************* ** This file contains the C functions that implement mutexes for win32 ** -** $Id: mutex_w32.c,v 1.3 2007/09/04 22:31:37 drh Exp $ +** $Id: mutex_w32.c,v 1.4 2007/09/05 14:30:42 drh Exp $ */ #include "sqliteInt.h" @@ -32,6 +32,33 @@ struct sqlite3_mutex { }; /* +** Return true (non-zero) if we are running under WinNT, Win2K, WinXP, +** or WinCE. Return false (zero) for Win95, Win98, or WinME. +** +** Here is an interesting observation: Win95, Win98, and WinME lack +** the LockFileEx() API. But we can still statically link against that +** API as long as we don't call it win running Win95/98/ME. A call to +** this routine is used to determine if the host is Win95/98/ME or +** WinNT/2K/XP so that we will know whether or not we can safely call +** the LockFileEx() API. +*/ +#if OS_WINCE +# define mutexIsNT() (1) +#else + static int mutexIsNT(void){ + static int osType = 0; + if( osType==0 ){ + OSVERSIONINFO sInfo; + sInfo.dwOSVersionInfoSize = sizeof(sInfo); + GetVersionEx(&sInfo); + osType = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1; + } + return osType==2; + } +#endif /* OS_WINCE */ + + +/* ** The sqlite3_mutex_alloc() routine allocates a new ** mutex and returns a pointer to it. If it returns NULL ** that means that a mutex could not be allocated. SQLite @@ -141,16 +168,10 @@ void sqlite3_mutex_enter(sqlite3_mutex *p){ p->nRef++; } int sqlite3_mutex_try(sqlite3_mutex *p){ - /* The TryEnterCriticalSection() interface is not available on all - ** windows systems. Since sqlite3_mutex_try() is only used as an - ** optimization, we can skip it on windows. */ - return SQLITE_BUSY; - -#if 0 /* Not Available */ int rc; assert( p ); assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); - if( TryEnterCriticalSection(&p->mutex) ){ + if( mutexIsNT() && TryEnterCriticalSection(&p->mutex) ){ p->owner = GetCurrentThreadId(); p->nRef++; rc = SQLITE_OK; @@ -158,7 +179,6 @@ int sqlite3_mutex_try(sqlite3_mutex *p){ rc = SQLITE_BUSY; } return rc; -#endif } /* |