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-rw-r--r--condvar.c46
1 files changed, 32 insertions, 14 deletions
diff --git a/condvar.c b/condvar.c
index f9230c1..c4e846b 100644
--- a/condvar.c
+++ b/condvar.c
@@ -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