PTHREAD_MUTEX_GETPRIOCEILING(3P)                    POSIX Programmer's Manual                   PTHREAD_MUTEX_GETPRIOCEILING(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_getprioceiling,  pthread_mutex_setprioceiling  -  get  and  set  the  priority ceiling of a mutex (REALTIME
       THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_mutex_getprioceiling(const pthread_mutex_t *restrict mutex,
              int *restrict prioceiling);
       int pthread_mutex_setprioceiling(pthread_mutex_t *restrict mutex,
              int prioceiling, int *restrict old_ceiling);


DESCRIPTION
       The pthread_mutex_getprioceiling() function shall return the current priority ceiling of the mutex.

       The pthread_mutex_setprioceiling() function shall either lock the mutex if it is unlocked, or block until it can success-
       fully  lock  the  mutex, then it shall change the mutex's priority ceiling and release the mutex. When the change is suc-
       cessful, the previous value of the priority ceiling shall be returned in old_ceiling. The process of  locking  the  mutex
       need not adhere to the priority protect protocol.

       If the pthread_mutex_setprioceiling() function fails, the mutex priority ceiling shall not be changed.

RETURN VALUE
       If  successful, the pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions shall return zero; other-
       wise, an error number shall be returned to indicate the error.

ERRORS
       The pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions may fail if:

       EINVAL The priority requested by prioceiling is out of range.

       EINVAL The value specified by mutex does not refer to a currently existing mutex.

       EPERM  The caller does not have the privilege to perform the operation.


       These functions shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread_mutex_destroy(),   pthread_mutex_lock(),   pthread_mutex_timedlock(),   the   Base    Definitions    volume    of
       IEEE Std 1003.1-2001, <pthread.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_GETPRIOCEILING(3P)