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

1  –  C Binding

    #include <pthread.h>
    int
    pthread_cond_timedwait (
             pthread_cond_t   *cond,
             pthread_mutex_t   *mutex,
             const struct timespec   *abstime);

2  –  Arguments

 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 broadcast. See the pthread_get_expiration_np()
    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.

3  –  Description

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

    o  The specified condition variable is signaled or broadcast.

    o  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(), except that
    this routine can return before a condition variable is signaled
    or broadcast, specifically, when the specified time expires. For
    more information, see the pthread_cond_wait() 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(), 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()
    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 that are supported for use with asynchronous
    cancelability enabled are those that disable asynchronous
    cancelability.

4  –  Return Values

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

    Return      Description

    0           Successful completion.
    [EINVAL]    The value specified by cond, mutex, or abstime is
                invalid, or

                Different mutexes are supplied for concurrent
                pthread_cond_timedwait()  operations or
                pthread_cond_wait()  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]    The Threads Library cannot acquire memory needed
                to block using a statically initialized condition
                variable.

5  –  Associated Routines

       pthread_cond_broadcast()
       pthread_cond_destroy()
       pthread_cond_init()
       pthread_cond_signal()
       pthread_cond_wait()
       pthread_get_expiration_np()