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