/*
** 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
** will unwind its stack and return an error. The argument
** to sqlite3_mutex_alloc() is one of these integer constants:
**
** <ul>
** <li> SQLITE_MUTEX_FAST
** <li> SQLITE_MUTEX_RECURSIVE
** <li> SQLITE_MUTEX_STATIC_MASTER
** <li> SQLITE_MUTEX_STATIC_MEM
** <li> SQLITE_MUTEX_STATIC_MEM2
** <li> SQLITE_MUTEX_STATIC_PRNG
** <li> SQLITE_MUTEX_STATIC_LRU
** <li> SQLITE_MUTEX_STATIC_PMEM
** </ul>
**
** The first two constants cause sqlite3_mutex_alloc() to create
** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
** The mutex implementation does not need to make a distinction
** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
** not want to. But SQLite will only request a recursive mutex in
** cases where it really needs one. If a faster non-recursive mutex
** implementation is available on the host platform, the mutex subsystem
** might return such a mutex in response to SQLITE_MUTEX_FAST.
**
** The other allowed parameters to sqlite3_mutex_alloc() each return
** a pointer to a static preexisting mutex. Six static mutexes are
** used by the current version of SQLite. Future versions of SQLite
** may add additional static mutexes. Static mutexes are for internal
** use by SQLite only. Applications that use SQLite mutexes should
** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
** SQLITE_MUTEX_RECURSIVE.
**
** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
** returns a different mutex on every call. But for the static
** mutex types, the same mutex is returned on every call that has
** the same type number.
*/
static sqlite3_mutex *vmsMutexAlloc(int iType){
static sqlite3_mutex staticMutexes[] = {
SQLITE3_MUTEX_INITIALIZER("SQLITE3_MUTEX_STATIC_MASTER"),
SQLITE3_MUTEX_INITIALIZER("SQLITE3_MUTEX_STATIC_MEM"),
SQLITE3_MUTEX_INITIALIZER("SQLITE3_MUTEX_STATIC_MEM2"),
SQLITE3_MUTEX_INITIALIZER("SQLITE3_MUTEX_STATIC_PRNG"),
SQLITE3_MUTEX_INITIALIZER("SQLITE3_MUTEX_STATIC_LRU"),
SQLITE3_MUTEX_INITIALIZER("SQLITE3_MUTEX_STATIC_PMEM")
};
sqlite3_mutex *p;
switch( iType ){
case SQLITE_MUTEX_RECURSIVE: {
p = sqlite3MallocZero( sizeof(*p) );
if( p ){
#ifdef vax
/*
** On OpenVMS VAX there is no way to create a recursive mutex in
** the tis interface. The routine tis_mutex_initwithname is in
** the header file and claims to enable this. However, it does
** not actually exist in the CMA$TIS_SHR RTL. So, while the
** jiggery-pokery of the lock field in pthread_mutex_t below is
** completely unsupported it does, in fact, seem to work.
*/
tis_mutex_init(&p->mutex);
p->mutex.lock &= ~_PTHREAD_MSTATE_TYPE; /* Clear mutex type */
p->mutex.lock |= _PTHREAD_MTYPE_RECURS; /* Set mutex type to recursive */
#else
/*
** Although not documented, this is the routine used by the
** CRTL on Alpha and I64 to implement the flock() routine.
*/
tis_mutex_init_type(&p->mutex, PTHREAD_MUTEX_RECURSIVE, 0);
#endif
}
break;
}
case SQLITE_MUTEX_FAST: {
p = sqlite3MallocZero( sizeof(*p) );
if( p ){
tis_mutex_init(&p->mutex);
}
break;
}
default: {
assert( iType-2 >= 0 );
assert( iType-2 < ArraySize(staticMutexes) );
p = &staticMutexes[iType-2];
break;
}
}
return p;
}
pwr_tStatus
sync_MutexInit (
thread_sMutex *mp
)
{
#if defined OS_ELN
pwr_tStatus sts = SYNC__SUCCESS;
ELN$CREATE_MUTEX(*mp, &sts);
return sts;
#elif defined OS_LYNX && defined PWR_LYNX_30
return errno_Pstatus(pthread_mutex_init(mp, NULL));
#elif defined OS_POSIX
return errno_Status(pthread_mutex_init(mp, NULL));
#elif defined OS_VMS
return errno_Status(tis_mutex_init(mp));
#else
# error Not defined for this platform !
#endif
}
