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 .