get and set the prioceiling attribute of the  mutex  attributes  object
       (REALTIME THREADS)

SYNOPSIS
       #include <pthread.h>

       int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *
              restrict attr, int *restrict prioceiling);
       int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
              int prioceiling);


DESCRIPTION
       The  pthread_mutexattr_getprioceiling()  and pthread_mutexattr_setprio-
       ceiling() functions, respectively, shall get and set the priority ceil-
       ing attribute of a mutex attributes object pointed to by attr which was
       previously created by the function pthread_mutexattr_init().

       The prioceiling attribute contains the priority ceiling of  initialized
       mutexes. The values of prioceiling are within the maximum range of pri-
       orities defined by SCHED_FIFO.

       The prioceiling attribute defines the priority ceiling  of  initialized
       mutexes, which is the minimum priority level at which the critical sec-
       tion guarded by the mutex is  executed.  In  order  to  avoid  priority
       inversion, the priority ceiling of the mutex shall be set to a priority
       higher than or equal to the highest priority of all  the  threads  that
       may  lock  that mutex. The values of prioceiling are within the maximum
       range of priorities defined under the SCHED_FIFO scheduling policy.

RETURN VALUE
       Upon successful completion, the pthread_mutexattr_getprioceiling()  and
       pthread_mutexattr_setprioceiling()  functions shall return zero; other-
       wise, an error number shall be returned to indicate the error.

ERRORS
       The pthread_mutexattr_getprioceiling()  and  pthread_mutexattr_setprio-
       ceiling() functions may fail if:

       EINVAL The value specified by attr or prioceiling is invalid.

       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.

       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 .