te
Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved.
Copyright (c) 2001, the Institute of Electrical and Electronics Engineers, Inc. and The Open Group. All Rights Reserved.
Copyright 1991, 1992, 1994, The X/Open Company Ltd.
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 Sun OS 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]
pthread_mutex_getprioceiling, pthread_mutex_setprioceiling - change priority ceiling of a mutex

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

The pthread_mutex_getprioceiling() function returns the current priority ceiling of the mutex.

The pthread_mutex_setprioceiling() function either locks the mutex if it is unlocked, or blocks until it can successfully lock the mutex, then it changes the mutex's priority ceiling and releases the mutex. When the change is successful, the previous value of the priority ceiling is 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 is not changed.

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).

The ceiling value should not be treated as a persistent value resident in a pthread_mutex_t that is valid across upgrades of Solaris. The semantics of the actual ceiling value are determined by the existing priority range for the SCHED_FIFO policy, as returned by the sched_get_priority_min() and sched_get_priority_max() functions (see sched_get_priority_min(3C)) when called on the version of Solaris on which the ceiling value is being utilized.

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

The pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions may fail if: EINVAL

The pthread_mutex_setprioceiling() function will fail if: EINVAL

EINVAL EPERM

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE

Interface Stability Committed

MT-Level MT-Safe

Standard See standards(5).

pthread_mutex_init(3C), pthread_mutex_lock(3C), sched_get_priority_min(3C), attributes(5), standards(5)