diff options
Diffstat (limited to 'mysys')
| -rw-r--r-- | mysys/my_winsem.c | 174 |
1 files changed, 74 insertions, 100 deletions
diff --git a/mysys/my_winsem.c b/mysys/my_winsem.c index d45b43a4473..268a05a0b21 100644 --- a/mysys/my_winsem.c +++ b/mysys/my_winsem.c @@ -4,10 +4,10 @@ * Module: my_semaphore.c (Original: semaphore.c from pthreads library) * * Purpose: - * Semaphores aren't actually part of the PThreads standard. - * They are defined by the POSIX Standard: + * Semaphores aren't actually part of the PThreads standard. + * They are defined by the POSIX Standard: * - * POSIX 1003.1b-1993 (POSIX.1b) + * POSIX 1003.1b-1993 (POSIX.1b) * * ------------------------------------------------------------- * @@ -52,33 +52,27 @@ DOCPUBLIC This function initializes an unnamed semaphore. the initial value of the semaphore is 'value' - + PARAMETERS - sem - pointer to an instance of sem_t - - pshared - if zero, this semaphore may only be shared between - threads in the same process. - if nonzero, the semaphore can be shared between - processes - - value - initial value of the semaphore counter - - DESCRIPTION - This function initializes an unnamed semaphore. The - initial value of the semaphore is set to 'value'. - + sem Pointer to an instance of sem_t + + pshared If zero, this semaphore may only be shared between + threads in the same process. + If nonzero, the semaphore can be shared between + processes + + value Initial value of the semaphore counter + RESULTS - 0 successfully created semaphore, - -1 failed, error in errno + 0 Successfully created semaphore, + -1 Failed, error in errno + ERRNO - EINVAL 'sem' is not a valid semaphore, - ENOSPC a required resource has been exhausted, - ENOSYS semaphores are not supported, - EPERM the process lacks appropriate privilege - + EINVAL 'sem' is not a valid semaphore, + ENOSPC A required resource has been exhausted, + ENOSYS Semaphores are not supported, + EPERM The process lacks appropriate privilege + */ int @@ -111,10 +105,10 @@ sem_init (sem_t *sem, int pshared, unsigned int value) InitializeCriticalSection(&sem->sem_lock_cs); } #else /* HAVE_CREATESEMAPHORE */ - *sem = CreateSemaphore (NULL, /* Always NULL */ - value, /* Initial value */ + *sem = CreateSemaphore (NULL, /* Always NULL */ + value, /* Initial value */ 0x7FFFFFFFL, /* Maximum value */ - NULL); /* Name */ + NULL); /* Name */ if (!*sem) result = ENOSPC; #endif /* HAVE_CREATESEMAPHORE */ @@ -133,20 +127,15 @@ sem_init (sem_t *sem, int pshared, unsigned int value) This function destroys an unnamed semaphore. PARAMETERS - sem - pointer to an instance of sem_t - - DESCRIPTION - This function destroys an unnamed semaphore. + sem Pointer to an instance of sem_t RESULTS - 0 successfully destroyed semaphore, - -1 failed, error in errno + 0 Successfully destroyed semaphore, + -1 Failed, error in errno ERRNO - EINVAL 'sem' is not a valid semaphore, - ENOSYS semaphores are not supported, - EBUSY threads (or processes) are currently - blocked on 'sem' + EINVAL 'sem' is not a valid semaphore, + ENOSYS Semaphores are not supported, + EBUSY Threads (or processes) are currently blocked on 'sem' */ int @@ -154,7 +143,7 @@ sem_destroy (sem_t * sem) { int result = 0; -#ifdef EXTRA_DEBUG +#ifdef EXTRA_DEBUG if (sem == NULL || *sem == NULL) { errno=EINVAL; @@ -183,27 +172,24 @@ sem_destroy (sem_t * sem) /* DOCPUBLIC - This function tries to wait on a semaphore. - - PARAMETERS - sem - pointer to an instance of sem_t - - DESCRIPTION This function tries to wait on a semaphore. If the semaphore value is greater than zero, it decreases its value by one. If the semaphore value is zero, then this function returns immediately with the error EAGAIN + PARAMETERS + sem Pointer to an instance of sem_t + RESULTS - 0 successfully decreased semaphore, - -1 failed, error in errno + 0 Successfully decreased semaphore, + -1 Failed, error in errno + ERRNO - EAGAIN the semaphore was already locked, - EINVAL 'sem' is not a valid semaphore, - ENOSYS semaphores are not supported, - EINTR the function was interrupted by a signal, - EDEADLK a deadlock condition was detected. + EAGAIN The semaphore was already locked, + EINVAL 'sem' is not a valid semaphore, + ENOSYS Semaphores are not supported, + EINTR The function was interrupted by a signal, + EDEADLK A deadlock condition was detected. */ int @@ -214,7 +200,7 @@ sem_trywait(sem_t * sem) int errno = EINVAL; return -1; #else /* HAVE_CREATESEMAPHORE */ -#ifdef EXTRA_DEBUG +#ifdef EXTRA_DEBUG if (sem == NULL || *sem == NULL) { errno=EINVAL; @@ -234,7 +220,7 @@ sem_trywait(sem_t * sem) #ifndef HAVE_CREATESEMAPHORE -static void +static void ptw32_decrease_semaphore(sem_t * sem) { EnterCriticalSection(&sem->sem_lock_cs); @@ -267,13 +253,6 @@ ptw32_increase_semaphore(sem_t * sem, unsigned int n) /* ------------------------------------------------------ DOCPUBLIC - This function waits on a semaphore. - - PARAMETERS - sem - pointer to an instance of sem_t - - DESCRIPTION This function waits on a semaphore. If the semaphore value is greater than zero, it decreases its value by one. If the semaphore value is zero, then @@ -281,15 +260,18 @@ ptw32_increase_semaphore(sem_t * sem, unsigned int n) successfully decrease the value or until interrupted by a signal. + PARAMETERS + sem Pointer to an instance of sem_t + RESULTS - 0 successfully decreased semaphore, - -1 failed, error in errno - ERRNO - EINVAL 'sem' is not a valid semaphore, - ENOSYS semaphores are not supported, - EINTR the function was interrupted by a signal, - EDEADLK a deadlock condition was detected. + 0 Successfully decreased semaphore, + -1 Failed, error in errno + ERRNO + EINVAL 'Sem' is not a valid semaphore, + ENOSYS Semaphores are not supported, + EINTR The function was interrupted by a signal, + EDEADLK A deadlock condition was detected. */ int @@ -297,7 +279,7 @@ sem_wait(sem_t *sem) { int result; -#ifdef EXTRA_DEBUG +#ifdef EXTRA_DEBUG if (sem == NULL || *sem == NULL) { errno=EINVAL; @@ -331,30 +313,27 @@ sem_wait(sem_t *sem) /* ------------------------------------------------------ DOCPUBLIC - This function posts a wakeup to a semaphore. - - PARAMETERS - sem - pointer to an instance of sem_t - - DESCRIPTION This function posts a wakeup to a semaphore. If there are waiting threads (or processes), one is awakened; otherwise, the semaphore value is incremented by one. + PARAMETERS + sem Pointer to an instance of sem_t + RESULTS - 0 successfully posted semaphore, - -1 failed, error in errno + 0 Successfully posted semaphore, + -1 Failed, error in errno + ERRNO - EINVAL 'sem' is not a valid semaphore, - ENOSYS semaphores are not supported, + EINVAL 'sem' is not a valid semaphore, + ENOSYS Semaphores are not supported, */ int sem_post (sem_t * sem) { -#ifdef EXTRA_DEBUG +#ifdef EXTRA_DEBUG if (sem == NULL || *sem == NULL) { errno=EINVAL; @@ -378,32 +357,27 @@ sem_post (sem_t * sem) /* ------------------------------------------------------ DOCPUBLIC - This function posts multiple wakeups to a semaphore. - - PARAMETERS - sem - pointer to an instance of sem_t - - count - counter, must be greater than zero. - - DESCRIPTION This function posts multiple wakeups to a semaphore. If there are waiting threads (or processes), n <= count are awakened; the semaphore value is incremented by count - n. + PARAMETERS + sem Pointer to an instance of sem_t + count Counter, must be greater than zero. + RESULTS - 0 successfully posted semaphore, - -1 failed, error in errno + 0 Successfully posted semaphore, + -1 Failed, error in errno + ERRNO - EINVAL 'sem' is not a valid semaphore - or count is less than or equal to zero. + EINVAL 'sem' is not a valid semaphore or count is less + than or equal to zero. */ int sem_post_multiple (sem_t * sem, int count ) { -#ifdef EXTRA_DEBUG +#ifdef EXTRA_DEBUG if (sem == NULL || *sem == NULL || count <= 0) { errno=EINVAL; |