1.\" Copyright (c) 1998 Alex Nash 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/lib/libc_r/man/pthread_rwlock_unlock.3,v 1.2.2.2 2001/12/17 10:08:26 ru Exp $ 26.\" $DragonFly: src/lib/libc_r/man/pthread_rwlock_unlock.3,v 1.3 2006/02/17 19:35:07 swildner Exp $ 27.\" 28.Dd April 15, 2009 29.Dt PTHREAD_RWLOCK_UNLOCK 3 30.Os 31.Sh NAME 32.Nm pthread_rwlock_unlock 33.Nd release a read/write lock 34.Sh LIBRARY 35.Lb libpthread 36.Sh SYNOPSIS 37.In pthread.h 38.Ft int 39.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock" 40.Sh DESCRIPTION 41The 42.Fn pthread_rwlock_unlock 43function is used to release the read/write lock previously obtained by 44.Fn pthread_rwlock_rdlock , 45.Fn pthread_rwlock_wrlock , 46.Fn pthread_rwlock_tryrdlock , 47or 48.Fn pthread_rwlock_trywrlock . 49.Sh RETURN VALUES 50If successful, the 51.Fn pthread_rwlock_unlock 52function will return zero. Otherwise an error number will be returned 53to indicate the error. 54.Pp 55The results are undefined if 56.Fa lock 57is not held by the calling thread. 58.Sh ERRORS 59The 60.Fn pthread_rwlock_unlock 61function may fail if: 62.Bl -tag -width Er 63.It Bq Er EINVAL 64The value specified by 65.Fa lock 66is invalid. 67.It Bq Er EPERM 68The current thread does not own the read/write lock. 69.El 70.Sh SEE ALSO 71.Xr pthread_rwlock_rdlock 3 , 72.Xr pthread_rwlock_wrlock 3 73.Sh STANDARDS 74The 75.Fn pthread_rwlock_unlock 76function is expected to conform to 77.St -susv2 . 78.Sh HISTORY 79The 80.Fn pthread_rwlock_unlock 81function first appeared in 82.Fx 3.0 . 83