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.Sh SYNOPSIS 36.In pthread.h 37.Ft int 38.Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr" 39.Sh DESCRIPTION 40The 41.Fn pthread_rwlock_init 42function is used to initialize a read/write lock, with attributes 43specified by 44.Fa attr . 45If 46.Fa attr 47is NULL, the default read/write lock attributes are used. 48.Pp 49The results of calling 50.Fn pthread_rwlock_init 51with an already initialized lock are undefined. 52.Sh RETURN VALUES 53If successful, the 54.Fn pthread_rwlock_init 55function will return zero. Otherwise an error number will be returned 56to indicate the error. 57.Sh SEE ALSO 58.Xr pthread_rwlockattr_init 3 , 59.Xr pthread_rwlockattr_setpshared 3 , 60.Xr pthread_rwlock_destroy 3 61.Sh STANDARDS 62The 63.Fn pthread_rwlock_init 64function is expected to conform to 65.St -susv2 . 66.Sh ERRORS 67The 68.Fn pthread_rwlock_init 69function will fail if: 70.Bl -tag -width Er 71.It Bq Er EAGAIN 72The system lacked the necessary resources (other than memory) to 73initialize the lock. 74.It Bq Er ENOMEM 75Insufficient memory exists to initialize the lock. 76.It Bq Er EPERM 77The caller does not have sufficient privilege to perform the 78operation. 79.El 80.Pp 81The 82.Fn pthread_rwlock_init 83function may fail if: 84.Bl -tag -width Er 85.It Bq Er EBUSY 86The system has detected an attempt to re-initialize the object 87referenced by 88.Fa lock , 89a previously initialized but not yet destroyed read/write lock. 90.It Bq Er EINVAL 91The value specified by 92.Fa attr 93is invalid. 94.El 95.Sh HISTORY 96The 97.Fn pthread_rwlock_init 98function first appeared in 99.Fx 3.0 . 100.Sh BUGS 101The PTHREAD_PROCESS_SHARED attribute is not supported. 102