NetBSD/lib/libpthread/pthread_rwlock_init.3

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.\" $NetBSD: pthread_rwlock_init.3,v 1.6 2005/03/21 17:55:07 kleink Exp $
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of The NetBSD Foundation nor the names of its
.\" contributors may be used to endorse or promote products derived
.\" from this software without specific prior written permission.
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\"
.\" Copyright (c) 1998 Alex Nash
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: src/lib/libpthread/man/pthread_rwlock_init.3,v 1.6 2002/09/16 19:29:29 mini Exp $
.\"
.Dd January 30, 2003
.Dt PTHREAD_RWLOCK_INIT 3
.Os
.Sh NAME
.Nm pthread_rwlock_init
.Nd initialize a read/write lock
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_rwlock_init "pthread_rwlock_t * restrict lock" "const pthread_rwlockattr_t * restrict attr"
.Sh DESCRIPTION
The
.Fn pthread_rwlock_init
function is used to initialize a read/write lock, with attributes
specified by
.Fa attr .
If
.Fa attr
is NULL, the default read/write lock attributes are used.
.Pp
The results of calling
.Fn pthread_rwlock_init
with an already initialized lock are undefined.
.Sh RETURN VALUES
If successful, the
.Fn pthread_rwlock_init
function will return zero. Otherwise an error number will be returned
to indicate the error.
.Sh ERRORS
The
.Fn pthread_rwlock_init
function shall fail if:
.Bl -tag -width Er
.It Bq Er EAGAIN
The system lacks the resources to initialize another read-write lock.
.It Bq Er ENOMEM
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Insufficient memory exists to initialize the read-write lock.
.El
.Pp
The
.Fn pthread_rwlock_init
function may fail if:
.Bl -tag -width Er
.It Bq Er EBUSY
The system has detected an attempt to re-initialize the object
referenced by
.Fa lock ,
a previously initialized but not yet destroyed read/write lock.
.It Bq Er EINVAL
The value specified by
.Fa attr
is invalid.
.El
.Sh SEE ALSO
.Xr pthread_rwlock_destroy 3 ,
.Xr pthread_rwlock_rdlock 3 ,
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.Xr pthread_rwlock_unlock 3 ,
.Xr pthread_rwlock_wrlock 3
.Sh STANDARDS
.Fn pthread_rwlock_init
conforms to
.St -p1003.1-96 .
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.Sh BUGS
The PTHREAD_PROCESS_SHARED attribute is not supported.