[apple/libc.git] / pthreads / pthread_rwlock_init.3

.\" 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/libc_r/man/pthread_rwlock_init.3,v 1.5 2001/10/01 16:09:09 ru Exp $
.\"
.Dd August 4, 1998
.Dt PTHREAD_RWLOCK_INIT 3
.Os
.Sh NAME
.Nm pthread_rwlock_init
.Nd initialize a read/write lock
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fo pthread_rwlock_init
.Fa "pthread_rwlock_t *restrict rwlock"
.Fa "const pthread_rwlockattr_t *restrict attr"
.Fc
.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 SEE ALSO
.Xr pthread_rwlock_destroy 3 ,
.Xr pthread_rwlockattr_init 3 ,
.Xr pthread_rwlockattr_setpshared 3
.Sh STANDARDS
The
.Fn pthread_rwlock_init
function is expected to conform to
.St -susv2 .
.Sh ERRORS
The
.Fn pthread_rwlock_init
function will fail if:
.Bl -tag -width Er
.It Bq Er EAGAIN
The system lacked the necessary resources (other than memory) to
initialize the lock.
.It Bq Er ENOMEM
Insufficient memory exists to initialize the lock.
.It Bq Er EPERM
The caller does not have sufficient privilege to perform the
operation.
.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 rwlock ,
a previously initialized but not yet destroyed read/write lock.
.It Bq Er EINVAL
The value specified by
.Fa attr
is invalid.
.El
.Sh HISTORY
The
.Fn pthread_rwlock_init
function first appeared in
.Fx 3.0 .
.Sh BUGS
The PTHREAD_PROCESS_SHARED attribute is not supported.
Commit	Line	Data
5b2abdfb A	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: src/lib/libc_r/man/pthread_rwlock_init.3,v 1.5 2001/10/01 16:09:09 ru Exp $
	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	.In pthread.h
	35	.Ft int
224c7076 A	36	.Fo pthread_rwlock_init
	37	.Fa "pthread_rwlock_t *restrict rwlock"
	38	.Fa "const pthread_rwlockattr_t *restrict attr"
	39	.Fc
5b2abdfb A	40	.Sh DESCRIPTION
	41	The
	42	.Fn pthread_rwlock_init
	43	function is used to initialize a read/write lock, with attributes
	44	specified by
	45	.Fa attr .
	46	If
	47	.Fa attr
	48	is NULL, the default read/write lock attributes are used.
	49	.Pp
	50	The results of calling
	51	.Fn pthread_rwlock_init
	52	with an already initialized lock are undefined.
	53	.Sh RETURN VALUES
	54	If successful, the
	55	.Fn pthread_rwlock_init
224c7076 A	56	function will return zero.
224c7076 A	57	Otherwise, an error number will be returned to indicate the error.
5b2abdfb	58	.Sh SEE ALSO
224c7076	59	.Xr pthread_rwlock_destroy 3 ,
5b2abdfb	60	.Xr pthread_rwlockattr_init 3 ,
224c7076	61	.Xr pthread_rwlockattr_setpshared 3
5b2abdfb A	62	.Sh STANDARDS
	63	The
	64	.Fn pthread_rwlock_init
	65	function is expected to conform to
	66	.St -susv2 .
	67	.Sh ERRORS
	68	The
	69	.Fn pthread_rwlock_init
	70	function will fail if:
	71	.Bl -tag -width Er
	72	.It Bq Er EAGAIN
	73	The system lacked the necessary resources (other than memory) to
	74	initialize the lock.
	75	.It Bq Er ENOMEM
	76	Insufficient memory exists to initialize the lock.
	77	.It Bq Er EPERM
	78	The caller does not have sufficient privilege to perform the
	79	operation.
	80	.El
	81	.Pp
	82	The
	83	.Fn pthread_rwlock_init
	84	function may fail if:
	85	.Bl -tag -width Er
	86	.It Bq Er EBUSY
	87	The system has detected an attempt to re-initialize the object
	88	referenced by
224c7076	89	.Fa rwlock ,
5b2abdfb A	90	a previously initialized but not yet destroyed read/write lock.
	91	.It Bq Er EINVAL
	92	The value specified by
	93	.Fa attr
	94	is invalid.
	95	.El
	96	.Sh HISTORY
	97	The
	98	.Fn pthread_rwlock_init
	99	function first appeared in
	100	.Fx 3.0 .
	101	.Sh BUGS
	102	The PTHREAD_PROCESS_SHARED attribute is not supported.