PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

PTHREAD_MUTEX_TIMEDLOCK(3P)OSIX Programmer's ManualHREAD_MUTEX_TIMEDLOCK(3P)

PROLOG         top

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

NAME         top

       pthread_mutex_timedlock — lock a mutex

SYNOPSIS         top

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

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

DESCRIPTION         top

       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 abstime
       passes, as measured by the clock on which timeouts are based (that
       is, when the value of that clock equals or exceeds abstime), or if
       the absolute time specified by abstime has already been passed at the
       time of the call.

       The timeout shall be based on the CLOCK_REALTIME clock.  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 abstime
       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.

       If mutex is a robust mutex and the process containing the owning
       thread terminated while holding the mutex lock, a call to
       pthread_mutex_timedlock() shall return the error value [EOWNERDEAD].
       If mutex is a robust mutex and the owning thread terminated while
       holding the mutex lock, a call to pthread_mutex_timedlock() may
       return the error value [EOWNERDEAD] even if the process in which the
       owning thread resides has not terminated. In these cases, the mutex
       is locked by the thread but the state it protects is marked as
       inconsistent. The application should ensure that the state is made
       consistent for reuse and when that is complete call
       pthread_mutex_consistent().  If the application is unable to recover
       the state, it should unlock the mutex without a prior call to
       pthread_mutex_consistent(), after which the mutex is marked
       permanently unusable.

       If mutex does not refer to an initialized mutex object, the behavior
       is undefined.

RETURN VALUE         top

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

ERRORS         top

       The pthread_mutex_timedlock() function shall fail if:

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

       EDEADLK
              The mutex type is PTHREAD_MUTEX_ERRORCHECK and the current
              thread already owns the mutex.

       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 abstime
              parameter specified a nanoseconds field value less than zero
              or greater than or equal to 1000 million.

       ENOTRECOVERABLE
              The state protected by the mutex is not recoverable.

       EOWNERDEAD
              The mutex is a robust mutex and the process containing the
              previous owning thread terminated while holding the mutex
              lock. The mutex lock shall be acquired by the calling thread
              and it is up to the new owner to make the state consistent.

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

       The pthread_mutex_timedlock() function may fail if:

       EDEADLK
              A deadlock condition was detected.

       EOWNERDEAD
              The mutex is a robust mutex and the previous owning thread
              terminated while holding the mutex lock. The mutex lock shall
              be acquired by the calling thread and it is up to the new
              owner to make the state consistent.

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

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       Applications that have assumed that non-zero return values are errors
       will need updating for use with robust mutexes, since a valid return
       for a thread acquiring a mutex which is protecting a currently
       inconsistent state is [EOWNERDEAD].  Applications that do not check
       the error returns, due to ruling out the possibility of such errors
       arising, should not use robust mutexes. If an application is supposed
       to work with normal and robust mutexes, it should check all return
       values for error conditions and if necessary take appropriate action.

RATIONALE         top

       Refer to pthread_mutex_lock(3p).

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       pthread_mutex_destroy(3p), pthread_mutex_lock(3p), time(3p)

       The Base Definitions volume of POSIX.1‐2008, Section 4.11, Memory
       Synchronization, pthread.h(0p), time.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013         PTHREAD_MUTEX_TIMEDLOCK(3P)

Pages that refer to this page: pthread.h(0p)time.h(0p)clock_getres(3p)pthread_mutex_destroy(3p)pthread_mutex_getprioceiling(3p)pthread_mutex_lock(3p)