1996-08-20 08:22:01 +00:00
|
|
|
.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
|
|
|
|
|
.\" 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. All advertising materials mentioning features or use of this software
|
|
|
|
|
.\" must display the following acknowledgement:
|
|
|
|
|
.\" This product includes software developed by John Birrell.
|
|
|
|
|
.\" 4. Neither the name of the author nor the names of any co-contributors
|
|
|
|
|
.\" may be used to endorse or promote products derived from this software
|
|
|
|
|
.\" without specific prior written permission.
|
|
|
|
|
.\"
|
|
|
|
|
.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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 REGENTS 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.
|
|
|
|
|
.\"
|
|
|
|
|
.Dd April 4, 1996
|
|
|
|
|
.Dt PTHREAD_ONCE 3
|
|
|
|
|
.Os BSD 4
|
|
|
|
|
.Sh NAME
|
|
|
|
|
.Nm pthread_once
|
|
|
|
|
.Nd dynamic package initialization
|
|
|
|
|
.Sh SYNOPSIS
|
|
|
|
|
.Fd #include <pthread.h>
|
|
|
|
|
.Pp
|
|
|
|
|
pthread_once
|
|
|
|
|
.Fa once_control
|
|
|
|
|
= PTHREAD_ONCE_INIT;
|
|
|
|
|
.Ft int
|
1998-03-23 13:07:17 +00:00
|
|
|
.Fn pthread_once "pthread_once_t *once_control" "void (*init_routine)(void)"
|
1996-08-20 08:22:01 +00:00
|
|
|
.Sh DESCRIPTION
|
|
|
|
|
The first call to
|
|
|
|
|
.Fn pthread_once
|
|
|
|
|
by any thread in a process, with a given
|
|
|
|
|
.Fa once_control ,
|
|
|
|
|
will call the
|
|
|
|
|
.Fn init_routine
|
|
|
|
|
with no arguments. Subsequent calls to
|
|
|
|
|
.Fn pthread_once
|
|
|
|
|
with the same
|
|
|
|
|
.Fa once_control
|
|
|
|
|
will not call the
|
|
|
|
|
.Fn init_routine .
|
|
|
|
|
On return from
|
|
|
|
|
.Fn pthread_once ,
|
|
|
|
|
it is guaranteed that
|
|
|
|
|
.Fn init_routine
|
|
|
|
|
has completed. The
|
|
|
|
|
.Fa once_control
|
|
|
|
|
parameter is used to determine whether the associated initialization
|
|
|
|
|
routine has been called.
|
|
|
|
|
.Pp
|
|
|
|
|
The function
|
|
|
|
|
.Fn pthread_once
|
|
|
|
|
is not a cancellation point. However, if
|
|
|
|
|
.Fn init_routine
|
|
|
|
|
is a cancellation point and is cancelled, the effect on
|
|
|
|
|
.Fa once_control is as if
|
|
|
|
|
.Fn pthread_once
|
|
|
|
|
was never called.
|
|
|
|
|
.Pp
|
|
|
|
|
The constant
|
|
|
|
|
.Fa PTHREAD_ONCE_INIT
|
|
|
|
|
is defined by header
|
|
|
|
|
.Aq Pa pthread.h .
|
|
|
|
|
.Pp
|
|
|
|
|
The behavior of
|
|
|
|
|
.Fn pthread_once
|
|
|
|
|
is undefined if
|
|
|
|
|
.Fa once_control
|
|
|
|
|
has automatic storage duration or is not initialized by
|
|
|
|
|
.Fa PTHREAD_ONCE_INIT .
|
|
|
|
|
.Pp
|
|
|
|
|
.Sh RETURN VALUES
|
|
|
|
|
If successful, the
|
|
|
|
|
.Fn pthread_once
|
|
|
|
|
function will return zero. Otherwise an error number will be returned to
|
|
|
|
|
indicate the error.
|
|
|
|
|
.Sh ERRORS
|
|
|
|
|
None.
|
|
|
|
|
.Pp
|
|
|
|
|
.Sh STANDARDS
|
|
|
|
|
.Fn pthread_once
|
1998-08-03 00:58:37 +00:00
|
|
|
conforms to ISO/IEC 9945-1 ANSI/IEEE
|
1996-08-20 08:22:01 +00:00
|
|
|
.Pq Dq Tn POSIX
|
1998-08-03 00:58:37 +00:00
|
|
|
Std 1003.1 Second Edition 1996-07-12.
|
