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 timeouts 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 necessary 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 implementations.

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, Copyright (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.opengroup.org/unix/online.html .