pthread_cond_timedwait(3) Library Functions Manual 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.
LIBRARY
DECthreads POSIX 1003.1c Library (libpthread.so)
SYNOPSIS
#include <pthread.h>
int pthread_cond_timedwait(
pthread_cond_t *cond,
pthread_mutex_t *mutex,
const struct timespec *abstime);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
PARAMETERS
Condition variable that the calling thread waits on. Mutex associated with the condition variable specified in cond. 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:
Successful completion. 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. The time specified by abstime expired. DECthreads cannot acquire memory needed to block using a
statically initialized condition variable.
ERRORS
None
RELATED INFORMATION
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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pthread_cond_timedwait(3)