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authorrpj <rpj>1999-01-20 00:01:23 +0000
committerrpj <rpj>1999-01-20 00:01:23 +0000
commit1f803d2545ae17d35ad40f3f2969b2af7a6382b2 (patch)
tree7fd1af9f7c52e49e290849dd14d91e738b8ccaca /semaphore.h
parent20f77eda55f874b939719ac0abda4405ecd20bf8 (diff)
Wed Jan 20 09:31:28 1999 Ross Johnson <rpj@ixobrychus.canberra.edu.au>
* pthread.h (pthread_mutexattr_t): Changed to a pointer. * mutex.c (pthread_mutex_init): Conditionally create Win32 mutex - from John Bossom's implementation. (pthread_mutex_destroy): Conditionally close Win32 mutex - from John Bossom's implementation. (pthread_mutexattr_init): Replaced by John Bossom's version. (pthread_mutexattr_destroy): Ditto. (pthread_mutexattr_getpshared): New function from John Bossom's implementation. (pthread_mutexattr_setpshared): New function from John Bossom's implementation. Tue Jan 19 18:27:42 1999 Ross Johnson <rpj@swan.canberra.edu.au> * pthread.h (pthreadCancelableTimedWait): New prototype. (pthreadCancelableWait): Remove second argument. * misc.c (CancelableWait): New static function is pthreadCancelableWait() renamed. (pthreadCancelableWait): Now just calls CancelableWait() with INFINITE timeout. (pthreadCancelableTimedWait): Just calls CancelableWait() with passed in timeout. * private.c (_pthread_sem_timedwait): 'abstime' arg really is absolute time. Calculate relative time to wait from current time before passing timeout to new routine pthreadCancelableTimedWait(). - Scott Lightner <scott@curriculum.com> Tue Jan 19 10:27:39 1999 Ross Johnson <rpj@ixobrychus.canberra.edu.au> * pthread.h (pthread_mutexattr_setforcecs_np): New prototype. * mutex.c (pthread_mutexattr_init): Init 'pshared' and 'forcecs' attributes to 0. (pthread_mutexattr_setforcecs_np): New function (not portable). * pthread.h (pthread_mutex_t): Add 'mutex' element. Set to NULL in PTHREAD_MUTEX_INITIALIZER. The pthread_mutex_*() routines will try to optimise performance by choosing either mutexes or critical sections as the basis for pthread mutexes for each indevidual mutex. (pthread_mutexattr_t_): Add 'forcecs' element. Some applications may choose to force use of critical sections if they know that:- the mutex is PROCESS_PRIVATE and, either the OS supports TryEnterCriticalSection() or pthread_mutex_trylock() will never be called on the mutex. This attribute will be setable via a non-portable routine. Note: We don't yet support PROCESS_SHARED mutexes, so the implementation as it stands will default to Win32 mutexes only if the OS doesn't support TryEnterCriticalSection. On Win9x, and early versions of NT 'forcecs' will need to be set in order to get critical section based mutexes. Sun Jan 17 12:01:26 1999 Ross Johnson <rpj@ixobrychus.canberra.edu.au> * pthread.h (PTHREAD_MUTEX_INITIALIZER): Init new 'staticinit' value to '1' and existing 'valid' value to '1'. * global.c (_pthread_mutex_test_init_lock): Add. * implement.h (_pthread_mutex_test_init_lock.): Add extern. * private.c (_pthread_processInitialize): Init critical section for global lock used by _mutex_check_need_init(). (_pthread_processTerminate): Ditto (:s/Init/Destroy/). * dll.c (dllMain): Move call to FreeLibrary() so that it is only called once when the process detaches. * mutex.c (_mutex_check_need_init): New static function to test and init PTHREAD_MUTEX_INITIALIZER mutexes. Provides serialised access to the internal state of the uninitialised static mutex. Called from pthread_mutex_trylock() and pthread_mutex_lock() which do a quick unguarded test to check if _mutex_check_need_init() needs to be called. This is safe as the test is conservative and is repeated inside the guarded section of _mutex_check_need_init(). Thus in all calls except the first calls to lock static mutexes, the additional overhead to lock any mutex is a single memory fetch and test for zero. * pthread.h (pthread_mutex_t_): Add 'staticinit' member. Mutexes initialised by PTHREAD_MUTEX_INITIALIZER aren't really initialised until the first attempt to lock it. Using the 'valid' flag (which flags the mutex as destroyed or not) to record this information would be messy. It is possible for a statically initialised mutex such as this to be destroyed before ever being used. * mutex.c (pthread_mutex_trylock): Call _mutex_check_need_init() to test/init PTHREAD_MUTEX_INITIALIZER mutexes. (pthread_mutex_lock): Ditto. (pthread_mutex_unlock): Add check to ensure we don't try to unlock an unitialised static mutex. (pthread_mutex_destroy): Add check to ensure we don't try to delete a critical section that we never created. Allows us to destroy a static mutex that has never been locked (and hence initialised). (pthread_mutex_init): Set 'staticinit' flag to 0 for the new mutex.
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