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_INIT 3 29.Os 30.Sh NAME 31.Nm pthread_rwlock_init 32.Nd initialize 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_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr" 41.Sh DESCRIPTION 42The 43.Fn pthread_rwlock_init 44function is used to initialize a read/write lock, with attributes 45specified by 46.Fa attr . 47If 48.Fa attr 49is NULL, the default read/write lock attributes are used. 50.Pp 51The results of calling 52.Fn pthread_rwlock_init 53with an already initialized lock are undefined. 54.Sh RETURN VALUES 55If successful, the 56.Fn pthread_rwlock_init 57function will return zero. Otherwise an error number will be returned 58to indicate the error. 59.Sh SEE ALSO 60.Xr pthread_rwlockattr_init 3 , 61.Xr pthread_rwlockattr_setpshared 3 , 62.Xr pthread_rwlock_destroy 3 63.Sh STANDARDS 64The 65.Fn pthread_rwlock_init 66function is expected to conform to 67.St -susv2 . 68.Sh ERRORS 69The 70.Fn pthread_rwlock_init 71function will fail if: 72.Bl -tag -width Er 73.It Bq Er EAGAIN 74The system lacked the necessary resources (other than memory) to 75initialize the lock. 76.It Bq Er ENOMEM 77Insufficient memory exists to initialize the lock. 78.It Bq Er EPERM 79The caller does not have sufficient privilege to perform the 80operation. 81.El 82.Pp 83The 84.Fn pthread_rwlock_init 85function may fail if: 86.Bl -tag -width Er 87.It Bq Er EBUSY 88The system has detected an attempt to re-initialize the object 89referenced by 90.Fa lock , 91a previously initialized but not yet destroyed read/write lock. 92.It Bq Er EINVAL 93The value specified by 94.Fa attr 95is invalid. 96.El 97.Sh HISTORY 98The 99.Fn pthread_rwlock_init 100function first appeared in 101.Fx 3.0 . 102.Sh BUGS 103The PTHREAD_PROCESS_SHARED attribute is not supported. 104