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.Lb libpthread 36.Lb libthr 37.Sh SYNOPSIS 38.In pthread.h 39.Ft int 40.Fn pthread_rwlock_unlock "pthread_rwlock_t *lock" 41.Sh DESCRIPTION 42The 43.Fn pthread_rwlock_unlock 44function is used to release the read/write lock previously obtained by 45.Fn pthread_rwlock_rdlock , 46.Fn pthread_rwlock_wrlock , 47.Fn pthread_rwlock_tryrdlock , 48or 49.Fn pthread_rwlock_trywrlock . 50.Sh RETURN VALUES 51If successful, the 52.Fn pthread_rwlock_unlock 53function will return zero. Otherwise an error number will be returned 54to indicate the error. 55.Pp 56The results are undefined if 57.Fa lock 58is not held by the calling thread. 59.Sh SEE ALSO 60.Xr pthread_rwlock_rdlock 3 , 61.Xr pthread_rwlock_wrlock 3 62.Sh STANDARDS 63The 64.Fn pthread_rwlock_unlock 65function is expected to conform to 66.St -susv2 . 67.Sh ERRORS 68The 69.Fn pthread_rwlock_unlock 70function may fail if: 71.Bl -tag -width Er 72.It Bq Er EINVAL 73The value specified by 74.Fa lock 75is invalid. 76.It Bq Er EPERM 77The current thread does not own the read/write lock. 78.El 79.Sh HISTORY 80The 81.Fn pthread_rwlock_unlock 82function first appeared in 83.Fx 3.0 . 84