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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 standards
  as follows:

  IEEE Std 1003.1c-1995, POSIX System Application Program Interface

PARAMETERS
  cond	    Condition variable to be signaled.

DESCRIPTION
  This routine unblocks at least one thread waiting on the specified
  condition 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_broadcast(3).

  The scheduling policy determines which thread is awakened.  For policies
  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 mutex
  should be locked by the thread calling pthread_cond_signal(3).



RETURN VALUES
  If an error condition occurs, this routine returns an integer value
  indicating the type of error.	 Possible return values are as follows:

  0	    Successful completion.

  [EINVAL]  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