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pthread_cond_signal(3) Library Functions Manual pthread_cond_signal(3) NAME pthread_cond_signal - Wakes at least one thread that is waiting on the specified condition variable. LIBRARY DECthreads POSIX 1003.1c Library (libpthread.so) SYNOPSIS #include <pthread.h> int pthread_cond_signal( pthread_cond_t *cond); STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: IEEE Std 1003.1c-1995, POSIX System Application Program Interface PARAMETERS Condition variable to be signaled. DESCRIPTION This routine unblocks at least one thread waiting on the specified con- dition variable cond. Calling this routine implies that data guarded by the associated mutex has changed, thus it might be possible for one of the waiting threads to proceed. In general, only one thread will be released. If no threads are waiting on the specified condition variable, this routine takes no action. The signal does not propagate to the next condition variable wait. This routine should be called when any thread waiting on the specified condition variable might find its predicate true, but only one thread should proceed. If more than one thread can proceed, or if any thread would not be able to proceed, then you must use pthread_cond_broad- cast(3). The scheduling policy determines which thread is awakened. For poli- cies SCHED_FIFO and SCHED_RR, a blocked thread is chosen in priority order, using first-in/first-out (FIFO) within priorities. You can call this routine even when the associated mutex is locked. However, if predictable scheduling behavior is required, then that mu- tex should be locked by the thread calling pthread_cond_signal(3). RETURN VALUES If an error condition occurs, this routine returns an integer value in- dicating the type of error. Possible return values are as follows: Successful completion. The value specified by cond is invalid. ERRORS None RELATED INFORMATION Functions: pthread_cond_broadcast(3), pthread_cond_destroy(3), pthread_cond_init(3), pthread_cond_timedwait(3), pthread_cond_wait(3) Manuals: Guide to DECthreads and Programmer's Guide delim off pthread_cond_signal(3)