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pthread_cond_timedwait(3)


NAME

  pthread_cond_timedwait - Causes a thread to wait for the specified
  condition variable to be signaled or broadcasted, such that it will awake
  after a specified period of time


SYNOPSIS

  #include <pthread.h>

  int pthread_cond_timedwait(
	  pthread_cond_t *cond,
	  pthread_mutex_t *mutex,
	  const struct timespec *abstime );


LIBRARY

  DECthreads POSIX 1003.1c Library (libpthread.so)


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 that the calling thread waits on.

  mutex
      Mutex associated with the condition variable specified in cond.

  abstime
      Absolute time at which the wait expires, if the condition has not been
      signaled or broadcasted.	See the pthread_get_expiration_np(3) routine,
      which is used to obtain a value for this argument. The abstime argument
      is specified in Universal Coordinated Time (UTC). In the UTC-based
      model, time is represented as seconds since the Epoch. The Epoch is
      defined as the time 0 hours, 0 minutes, 0 seconds, January 1st, 1970
      UTC. Seconds since the Epoch is a value interpreted as the number of
      seconds between a specified time and the Epoch.


DESCRIPTION

  This routine causes a thread to wait until one of the following occurs:

    ·  The specified condition variable is signaled or broadcasted.

    ·  The current system clock time is greater than or equal to the time
       specified by the abstime argument.

  This routine is identical to pthread_cond_wait(3), except that this routine
  can return before a condition variable is signaled or broadcasted;
  specifically, when the specified time expires. For more information, see
  the pthread_cond_wait(3) description.

  This routine atomically releases the mutex and causes the calling thread to
  wait on the condition. When the thread regains control after calling
  pthread_cond_timedwait(3), the mutex is locked and the thread is the owner.
  This is true regardless of why the wait ended. If general cancelability is
  enabled, the thread reacquires the mutex (blocking for it if necessary)
  before the cleanup handlers are run (or before the exception is raised).

  If the current time equals or exceeds the expiration time, this routine
  returns immediately, releasing and reacquiring the mutex. It might cause
  the calling thread to yield (see the sched_yield(3) description).  Your
  code should check the return status whenever this routine returns and take
  the appropriate action. Otherwise, waiting on the condition variable can
  become a nonblocking loop.

  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. The only routines which are supported for use with
  asynchronous cancelability enabled are those which disable asynchronous
  cancelability.


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, mutex, or abstime is invalid, or:
      Different mutexes are supplied for concurrent pthread_cond_timedwait(3)
      operations or pthread_cond_wait(3) operations on the same condition
      variable, or: The mutex was not owned by the calling thread at the time
      of the call.

  [ETIMEDOUT]
      The time specified by abstime expired.

  [ENOMEM]
      DECthreads cannot acquire memory needed to block using a statically
      initialized condition variable.


ERRORS

  None


SEE ALSO

  Functions: pthread_cond_broadcast(3), pthread_cond_destroy(3),
  pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_wait(3),
  pthread_get_expiration_np(3)

  Manuals: Guide to DECthreads and Programmer's Guide

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