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 SYNOPSIS 34.Fd #include <pthread.h> 35.Ft int 36.Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr" 37.Sh DESCRIPTION 38The 39.Fn pthread_rwlock_init 40function is used to initialize a read/write lock, with attributes 41specified by 42.Fa attr . 43If 44.Fa attr 45is NULL, the default read/write lock attributes are used. 46.Pp 47The results of calling 48.Fn pthread_rwlock_init 49with an already initialized lock are undefined. 50.Sh RETURN VALUES 51If successful, the 52.Fn pthread_rwlock_init 53function will return zero. Otherwise an error number will be returned 54to indicate the error. 55.Sh SEE ALSO 56.Xr pthread_rwlock_destroy 3 , 57.Xr pthread_rwlockattr_init 3 , 58.Xr pthread_rwlockattr_setpshared 3 59.Sh STANDARDS 60The 61.Fn pthread_rwlock_init 62function is expected to conform to 63.St -susv2 . 64.Sh ERRORS 65The 66.Fn pthread_rwlock_init 67function will fail if: 68.Bl -tag -width Er 69.It Bq Er EAGAIN 70The system lacked the necessary resources (other than memory) to 71initialize the lock. 72.It Bq Er ENOMEM 73Insufficient memory exists to initialize the lock. 74.It Bq Er EPERM 75The caller does not have sufficient privilege to perform the 76operation. 77.El 78.Pp 79The 80.Fn pthread_rwlock_init 81function may fail if: 82.Bl -tag -width Er 83.It Bq Er EBUSY 84The system has detected an attempt to re-initialize the object 85referenced by 86.Fa lock , 87a previously initialized but not yet destroyed read/write lock. 88.It Bq Er EINVAL 89The value specified by 90.Fa attr 91is invalid. 92.El 93.Sh HISTORY 94The 95.Fn pthread_rwlock_init 96function first appeared in 97.Fx 3.0 . 98.Sh BUGS 99The PTHREAD_PROCESS_SHARED attribute is not supported. 100