PTHREAD_MUTEX_TIMEDLOCK(3P)                         POSIX Programmer's Manual                        PTHREAD_MUTEX_TIMEDLOCK(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       pthread_mutex_timedlock - lock a mutex (ADVANCED REALTIME)

SYNOPSIS
       #include <pthread.h>
       #include <time.h>

       int pthread_mutex_timedlock(pthread_mutex_t *restrict mutex,
              const struct timespec *restrict abs_timeout);


DESCRIPTION
       The  pthread_mutex_timedlock()  function shall lock the mutex object referenced by mutex. If the mutex is already locked,
       the calling thread shall block until the mutex becomes available as in the pthread_mutex_lock() function.  If  the  mutex
       cannot be locked without waiting for another thread to unlock the mutex, this wait shall be terminated when the specified
       timeout expires.

       The timeout shall expire when the absolute time specified by abs_timeout passes, as measured by the clock on which  time-
       outs  are  based (that is, when the value of that clock equals or exceeds abs_timeout), or if the absolute time specified
       by abs_timeout has already been passed at the time of the call.

       If the Timers option is supported, the timeout shall be based on the CLOCK_REALTIME clock; if the Timers  option  is  not
       supported, the timeout shall be based on the system clock as returned by the time() function.

       The  resolution  of  the  timeout  shall  be  the resolution of the clock on which it is based. The timespec data type is
       defined in the <time.h> header.

       Under no circumstance shall the function fail with a timeout if the mutex can be locked immediately. The validity of  the
       abs_timeout parameter need not be checked if the mutex can be locked immediately.

       As  a  consequence of the priority inheritance rules (for mutexes initialized with the PRIO_INHERIT protocol), if a timed
       mutex wait is terminated because its timeout expires, the priority of the owner of the mutex shall be adjusted as  neces-
       sary to reflect the fact that this thread is no longer among the threads waiting for the mutex.

RETURN VALUE
       If  successful, the pthread_mutex_timedlock() function shall return zero; otherwise, an error number shall be returned to
       indicate the error.

ERRORS
       The pthread_mutex_timedlock() function shall fail if:

       EINVAL The mutex was created with the protocol attribute having the value PTHREAD_PRIO_PROTECT and the  calling  thread's
              priority is higher than the mutex' current priority ceiling.

       EINVAL The  process  or thread would have blocked, and the abs_timeout parameter specified a nanoseconds field value less
              than zero or greater than or equal to 1000 million.

       ETIMEDOUT
              The mutex could not be locked before the specified timeout expired.


       The pthread_mutex_timedlock() function may fail if:

       EINVAL The value specified by mutex does not refer to an initialized mutex object.

       EAGAIN The mutex could not be acquired because the maximum number of recursive locks for mutex has been exceeded.

       EDEADLK
              The current thread already owns the mutex.


       This function shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The pthread_mutex_timedlock() function is part of the Threads and Timeouts options and need not be provided on all imple-
       mentations.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_mutex_destroy(),   pthread_mutex_lock(),   pthread_mutex_trylock(),   time(),  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <pthread.h>, <time.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                   PTHREAD_MUTEX_TIMEDLOCK(3P)