diff options
Diffstat (limited to 'condvar.c')
| -rw-r--r-- | condvar.c | 46 |
1 files changed, 32 insertions, 14 deletions
@@ -543,20 +543,37 @@ pthread_cond_timedwait (pthread_cond_t * cond, * initial value of the semaphore is 'value' * * PARAMETERS - * sem - * pointer to an instance of sem_t + * cond + * pointer to an instance of pthread_cond_t + * + * mutex + * pointer to an instance of pthread_mutex_t + * + * abstime + * pointer to an instance of (const struct timespec) * * * DESCRIPTION - * This function initializes an unnamed semaphore. The - * initial value of the semaphore is set to 'value'. + * This function waits on a condition variable either until + * awakened by a signal or broadcast; or until the time + * specified by abstime passes. + * + * NOTES: + * 1) The function must be called with 'mutex' LOCKED + * by the calling thread, or undefined behaviour + * will result. + * + * 2) This routine atomically releases 'mutex' and causes + * the calling thread to block on the condition variable. + * The blocked thread may be awakened by + * pthread_cond_signal or + * pthread_cond_broadcast. * * RESULTS - * 0 successfully created semaphore, - * 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 + * 0 caught condition; mutex released, + * EINVAL 'cond' or 'mutex' is invalid, + * EINVAL different mutexes for concurrent waits, + * EINVAL mutex is not held by the calling thread, * * ------------------------------------------------------ */ @@ -636,13 +653,13 @@ pthread_cond_broadcast (pthread_cond_t * cond) * waking all current waiters. * * PARAMETERS - * sem + * cond * pointer to an instance of pthread_cond_t * * * DESCRIPTION - * This function initializes an unnamed semaphore. The - * initial value of the semaphore is set to 'value'. + * This function signals a condition variable, waking + * all waiting threads. * * NOTES: * 1) This function MUST be called under the protection @@ -657,7 +674,8 @@ pthread_cond_broadcast (pthread_cond_t * cond) * not be able to respond * * RESULTS - * 0 successfully created semaphore, + * 0 successfully signalled condition to all + * waiting threads, * EINVAL 'cond' is invalid * ENOSPC a required resource has been exhausted, * @@ -679,7 +697,7 @@ pthread_cond_broadcast (pthread_cond_t * cond) result = sem_post (&(cv->sema)); } - if (result == 0) + if (cv->waiters > 0 && result == 0) { /* * Wait for all the awakened threads to acquire their part of |