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. 58Otherwise an error number will be returned 59to indicate the error. 60.Sh SEE ALSO 61.Xr pthread_rwlockattr_init 3 , 62.Xr pthread_rwlockattr_setpshared 3 , 63.Xr pthread_rwlock_destroy 3 64.Sh STANDARDS 65The 66.Fn pthread_rwlock_init 67function is expected to conform to 68.St -susv2 . 69.Sh ERRORS 70The 71.Fn pthread_rwlock_init 72function will fail if: 73.Bl -tag -width Er 74.It Bq Er EAGAIN 75The system lacked the necessary resources (other than memory) to 76initialize the lock. 77.It Bq Er ENOMEM 78Insufficient memory exists to initialize the lock. 79.It Bq Er EPERM 80The caller does not have sufficient privilege to perform the 81operation. 82.El 83.Pp 84The 85.Fn pthread_rwlock_init 86function may fail if: 87.Bl -tag -width Er 88.It Bq Er EBUSY 89The system has detected an attempt to re-initialize the object 90referenced by 91.Fa lock , 92a previously initialized but not yet destroyed read/write lock. 93.It Bq Er EINVAL 94The value specified by 95.Fa attr 96is invalid. 97.El 98.Sh HISTORY 99The 100.Fn pthread_rwlock_init 101function first appeared in 102.Fx 3.0 . 103.Sh BUGS 104The PTHREAD_PROCESS_SHARED attribute is not supported. 105