pthread_cond_wait(3) [freebsd man page]
PTHREAD_COND_WAIT(3) BSD Library Functions Manual PTHREAD_COND_WAIT(3) NAME
pthread_cond_wait -- wait on a condition variable LIBRARY
POSIX Threads Library (libpthread, -lpthread) SYNOPSIS
#include <pthread.h> int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex); DESCRIPTION
The pthread_cond_wait() function atomically blocks the current thread waiting on the condition variable specified by cond, and releases the mutex specified by mutex. The waiting thread unblocks only after another thread calls pthread_cond_signal(3), or pthread_cond_broadcast(3) with the same condition variable, and the current thread reacquires the lock on mutex. RETURN VALUES
If successful, the pthread_cond_wait() function will return zero. Otherwise an error number will be returned to indicate the error. ERRORS
The pthread_cond_wait() function will fail if: [EINVAL] The value specified by cond or the value specified by mutex is invalid. [EPERM] The specified mutex was not locked by the calling thread. SEE ALSO
pthread_cond_broadcast(3), pthread_cond_destroy(3), pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_timedwait(3) STANDARDS
The pthread_cond_wait() function conforms to ISO/IEC 9945-1:1996 (``POSIX.1''). BSD
February 16, 2006 BSD
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pthread_cond_signal(3C) Standard C Library Functions pthread_cond_signal(3C) NAME
pthread_cond_signal, pthread_cond_broadcast - signal or broadcast a condition SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ] #include <pthread.h> int pthread_cond_signal(pthread_cond_t *cond); int pthread_cond_broadcast(pthread_cond_t *cond); DESCRIPTION
These two functions are used to unblock threads blocked on a condition variable. The pthread_cond_signal() call unblocks at least one of the threads that are blocked on the specified condition variable cond (if any threads are blocked on cond). The pthread_cond_broadcast() call unblocks all threads currently blocked on the specified condition variable cond. If more than one thread is blocked on a condition variable, the scheduling policy determines the order in which threads are unblocked. When each thread unblocked as a result of a pthread_cond_signal() or pthread_cond_broadcast() returns from its call to pthread_cond_wait() or pthread_cond_timedwait(), the thread owns the mutex with which it called pthread_cond_wait() or pthread_cond_timedwait(). The thread(s) that are unblocked contend for the mutex according to the scheduling policy (if applicable), and as if each had called pthread_mutex_lock(). The pthread_cond_signal() or pthread_cond_broadcast() functions may be called by a thread whether or not it currently owns the mutex that threads calling pthread_cond_wait() or pthread_cond_timedwait() have associated with the condition variable during their waits; however, if predictable scheduling behavior is required, then that mutex is locked by the thread calling pthread_cond_signal() or pthread_cond_broad- cast(). The pthread_cond_signal() and pthread_cond_broadcast() functions have no effect if there are no threads currently blocked on cond. RETURN VALUES
If successful, the pthread_cond_signal() and pthread_cond_broadcast() functions return 0. Otherwise, an error number is returned to indi- cate the error. ERRORS
The pthread_cond_signal() and pthread_cond_broadcast() function may fail if: EINVAL The value cond does not refer to an initialized condition variable. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
pthread_cond_init(3C), pthread_cond_wait(3C), pthread_cond_timedwait(3C), attributes(5), condition(5), standards(5) SunOS 5.11 23 Mar 2005 pthread_cond_signal(3C)