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 successfully lock the  mutex,  then  it  shall  change  the  mutex's
       priority  ceiling and release the mutex. When the change is successful, 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; otherwise, 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, 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 .