NAME

pthread_cond_wait - Causes a thread to wait for a condition variable to be signaled or broadcast

SYNOPSIS

#include <pthread.h> int pthread_cond_wait( pthread_cond_t *cond, pthread_mutex_t *mutex);

PARAMETERS

condCondition variable waited on. 

mutexMutex associated with the condition variable specified in cond. 

DESCRIPTION

The pthread_cond_wait() routine causes a thread to wait for a condition variable to be signaled or broadcast. Each condition corresponds to one or more predicates based on shared data. The calling thread waits for the data to reach a particular state (for the predicate to become true). Call this routine after you have locked the mutex specified in mutex. The results of this routine are unpredictable if this routine is called without first locking the mutex. This routine automatically releases the mutex and causes the calling thread to wait on the condition. If the wait is satisfied as a result of some thread calling pthread_cond_signal() or pthread_cond_broadcast(), the mutex is reacquired and the routine returns. A thread that changes the state of storage protected by the mutex in such a way that a predicate associated with a condition variable might now be true must call either pthread_cond_signal() or pthread_cond_broadcast() for that condition variable. If neither call is made, any thread waiting on the condition variable continues to wait. This routine might (with low probability) return when the condition variable has not been signaled or broadcast. When a spurious wakeup occurs, the mutex is reacquired before the routine returns. (To handle this type of situation, enclose this routine in a loop that checks the predicate.)

RETURN VALUES

If the function fails, errno may be set to one of the following values:

RELATED INFORMATION

Functions:  pthread_cond_broadcast(3), pthread_cond_destroy(3), pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_timedwait(3). 

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