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.\" $FreeBSD$ 26.\" 27.Dd August 4, 1998 28.Dt PTHREAD_RWLOCK_UNLOCK 3 29.Os 30.Sh NAME 31.Nm pthread_rwlock_unlock 32.Nd release a read/write lock 33.Sh LIBRARY 34.Lb libc_r 35.Sh SYNOPSIS 36.Fd #include <pthread.h> 37.Ft int 38.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock" 39.Sh DESCRIPTION 40The 41.Fn pthread_rwlock_unlock 42function is used to release the read/write lock previously obtained by 43.Fn pthread_rwlock_rdlock , 44.Fn pthread_rwlock_wrlock , 45.Fn pthread_rwlock_tryrdlock , 46or 47.Fn pthread_rwlock_trywrlock . 48.Sh RETURN VALUES 49If successful, the 50.Fn pthread_rwlock_unlock 51function will return zero. Otherwise an error number will be returned 52to indicate the error. 53.Pp 54The results are undefined if 55.Fa lock 56is not held by the calling thread. 57.Sh SEE ALSO 58.Xr pthread_rwlock_rdlock 3 , 59.Xr pthread_rwlock_wrlock 3 60.Sh STANDARDS 61The 62.Fn pthread_rwlock_unlock 63function is expected to conform to 64.St -susv2 . 65.Sh ERRORS 66The 67.Fn pthread_rwlock_unlock 68function may fail if: 69.Bl -tag -width Er 70.It Bq Er EINVAL 71The value specified by 72.Fa lock 73is invalid. 74.It Bq Er EPERM 75The current thread does not own the read/write lock. 76.El 77.Sh HISTORY 78The 79.Fn pthread_rwlock_unlock 80function first appeared in 81.Fx 3.0 . 82