PROLOG

       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

       pthread_mutexattr_getprioceiling,   pthread_mutexattr_setprioceiling   —  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_setprioceiling()  functions,  respectively,
       shall  get  and  set the priority ceiling 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 priorities defined by SCHED_FIFO.

       The  prioceiling  attribute  defines  the  priority  ceiling of initialized mutexes, which is the minimum
       priority level at which the critical section 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.

       The    behavior    is    undefined    if    the    value    specified    by    the   attr   argument   to
       pthread_mutexattr_getprioceiling() or pthread_mutexattr_setprioceiling() does not refer to an initialized
       mutex attributes object.

RETURN VALUE

       Upon successful completion, the pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling()
       functions shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

       These functions may fail if:

       EINVAL The value specified by 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.

RATIONALE

       If   an   implementation   detects   that   the   value   specified   by    the    attr    argument    to
       pthread_mutexattr_getprioceiling() or pthread_mutexattr_setprioceiling() does not refer to an initialized
       mutex attributes object, it is recommended that the function should fail and report an [EINVAL] error.

FUTURE DIRECTIONS

       None.

SEE ALSO

       pthread_cond_destroy(), pthread_create(), pthread_mutex_destroy()

       The Base Definitions volume of POSIX.1‐2008, <pthread.h>

COPYRIGHT

       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 .