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 libpthread 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. 56Otherwise an error number will be returned 57to indicate the error. 58.Sh ERRORS 59The 60.Fn pthread_rwlock_init 61function will fail if: 62.Bl -tag -width Er 63.It Bq Er EAGAIN 64The system lacked the necessary resources (other than memory) to 65initialize the lock. 66.It Bq Er ENOMEM 67Insufficient memory exists to initialize the lock. 68.It Bq Er EPERM 69The caller does not have sufficient privilege to perform the 70operation. 71.El 72.Pp 73The 74.Fn pthread_rwlock_init 75function may fail if: 76.Bl -tag -width Er 77.It Bq Er EBUSY 78The system has detected an attempt to re-initialize the object 79referenced by 80.Fa lock , 81a previously initialized but not yet destroyed read/write lock. 82.It Bq Er EINVAL 83The value specified by 84.Fa attr 85is invalid. 86.El 87.Sh SEE ALSO 88.Xr pthread_rwlock_destroy 3 , 89.Xr pthread_rwlockattr_init 3 , 90.Xr pthread_rwlockattr_setpshared 3 91.Sh STANDARDS 92The 93.Fn pthread_rwlock_init 94function is expected to conform to 95.St -susv2 . 96.Sh HISTORY 97The 98.Fn pthread_rwlock_init 99function first appeared in 100.Fx 3.0 . 101.Sh BUGS 102The PTHREAD_PROCESS_SHARED attribute is not supported. 103