Sun Microsystems, Inc. gratefully acknowledges The Open Group for
permission to reproduce portions of its copyrighted documentation.
Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.

The Institute of Electrical and Electronics Engineers and The Open
Group, have given us permission to reprint portions of their
documentation.

In the following statement, the phrase ``this text'' refers to portions
of the system documentation.

Portions of this text are reprinted and reproduced in electronic form
in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6,
Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy
between these versions 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.

This notice shall appear on any product containing this material.

The contents of this file are subject to the terms of the
Common Development and Distribution License (the "License").
You may not use this file except in compliance with the License.

You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
or http://www.opensolaris.org/os/licensing.
See the License for the specific language governing permissions
and limitations under the License.

When distributing Covered Code, include this CDDL HEADER in each
file and include the License file at usr/src/OPENSOLARIS.LICENSE.
If applicable, add the following below this CDDL HEADER, with the
fields enclosed by brackets "[]" replaced with your own identifying
information: Portions Copyright [yyyy] [name of copyright owner]


Copyright 1991, 1992, 1994, The X/Open Company Ltd.
Copyright (c) 2001, The IEEE and The Open Group. All Rights Reserved.
Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved.

pthread_mutexattr_getprioceiling, pthread_mutexattr_setprioceiling - get or set prioceiling attribute of mutex attribute object

cc -mt [ flag... ] file... -lpthread [ library... ]
#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);

The pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling() functions, respectively, get and set the priority ceiling attribute of a mutex attribute object pointed to by attr, which was previously created by the pthread_mutexattr_init() function.

The prioceiling attribute contains the priority ceiling of initialized mutexes. The values of prioceiling must be within the 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 must be set to a priority higher than or equal to the highest priority of all the threads that may lock that mutex.

The ceiling value should be drawn from the range of priorities for the SCHED_FIFO policy. When a thread acquires such a mutex, the policy of the thread at mutex acquisition should match that from which the ceiling value was derived (SCHED_FIFO, in this case). If a thread changes its scheduling policy while holding a ceiling mutex, the behavior of pthread_mutex_lock() and pthread_mutex_unlock() on this mutex is undefined. See pthread_mutex_lock(3C).

Upon successful completion, the pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling() functions return 0. Otherwise, an error number is returned to indicate the error.

The pthread_mutexattr_setprioceiling() function will fail if: EINVAL

The pthread_mutexattr_getprioceiling() and pthread_mutexattr_setprioceiling() functions may fail if: EINVAL

EPERM

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE

Interface Stability Committed

MT-Level MT-Safe

Standard See standards(7).

pthread_cond_init (3C), pthread_create (3C), pthread_mutex_init (3C), pthread_mutex_lock (3C), sched_get_priority_min (3C), attributes (7), standards (7)