pthread_cond_timedwait(3)pthread_cond_timedwait(3)NAMEpthread_cond_timedwait - Causes a thread to wait for the specified con‐
dition variable to be signaled or broadcasted, such that it will awake
after a specified period of time
const struct timespec *abstime );
DECthreads POSIX 1003.1c Library (libpthread.so)
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
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 broad‐
casted. 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 rep‐
resented 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 speci‐
fied time and the Epoch.
This routine causes a thread to wait until one of the following occurs:
The specified condition variable is signaled or broadcasted. The cur‐
rent 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 broad‐
casted; specifically, when the specified time expires. For more infor‐
mation, 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
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.
Functions: pthread_cond_broadcast(3), pthread_cond_destroy(3),
pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_wait(3),
Manuals: Guide to DECthreads and Programmer's Guide