2004-02-19 13:51:52 +00:00
|
|
|
.\" Copyright (c) 2004 Michael Telahun Makonnen
|
|
|
|
.\" 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.
|
|
|
|
.\"
|
|
|
|
.\" $FreeBSD$
|
|
|
|
.\"
|
|
|
|
.Dd February 19, 2004
|
2004-06-17 17:51:17 +00:00
|
|
|
.Dt PTHREAD_BARRIER 3
|
2004-02-19 13:51:52 +00:00
|
|
|
.Os
|
|
|
|
.Sh NAME
|
2004-06-17 17:51:17 +00:00
|
|
|
.Nm pthread_barrier_destroy , pthread_barrier_init , pthread_barrier_wait
|
2004-02-19 13:51:52 +00:00
|
|
|
.Nd "destroy, initialize or wait on a barrier object"
|
|
|
|
.Sh LIBRARY
|
|
|
|
.Lb libpthread
|
|
|
|
.Sh SYNOPSIS
|
|
|
|
.In pthread.h
|
|
|
|
.Ft int
|
|
|
|
.Fn pthread_barrier_destroy "pthread_barrier_t *barrier"
|
|
|
|
.Ft int
|
2005-11-24 15:10:38 +00:00
|
|
|
.Fn pthread_barrier_init "pthread_barrier_t *barrier" "const pthread_barrierattr_t *attr" "unsigned count"
|
2004-02-19 13:51:52 +00:00
|
|
|
.Ft int
|
|
|
|
.Fn pthread_barrier_wait "pthread_barrier_t *barrier"
|
|
|
|
.Sh DESCRIPTION
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_init
|
|
|
|
function will initialize
|
|
|
|
.Fa barrier
|
|
|
|
with attributes specified in
|
|
|
|
.Fa attr ,
|
2004-06-17 17:51:17 +00:00
|
|
|
or if it is
|
|
|
|
.Dv NULL ,
|
2004-02-19 13:51:52 +00:00
|
|
|
with default attributes.
|
|
|
|
The number of threads that must call
|
|
|
|
.Fn pthread_barrier_wait
|
|
|
|
before any of the waiting threads can be
|
|
|
|
released is specified by
|
|
|
|
.Fa count .
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_destroy
|
|
|
|
function will destroy
|
|
|
|
.Fa barrier
|
|
|
|
and release any resources that may have been allocated on its behalf.
|
|
|
|
.Pp
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_wait
|
|
|
|
function will synchronize calling threads at
|
|
|
|
.Fa barrier .
|
|
|
|
The threads will be blocked from
|
|
|
|
making further progress until
|
|
|
|
a sufficient number of threads calls this function.
|
|
|
|
The number of threads that must call it before
|
|
|
|
any of them will be released is determined by the
|
|
|
|
.Fa count
|
|
|
|
argument to
|
|
|
|
.Fn pthread_barrier_init .
|
|
|
|
Once the threads have been released the barrier will be reset.
|
2005-01-21 08:36:40 +00:00
|
|
|
.Sh IMPLEMENTATION NOTES
|
2016-05-29 18:25:11 +00:00
|
|
|
In
|
2005-01-21 08:36:40 +00:00
|
|
|
.Lb libthr
|
|
|
|
the
|
|
|
|
.Dv PTHREAD_BARRIER_SERIAL_THREAD
|
|
|
|
return value will
|
|
|
|
always be returned by the last thread to reach the barrier.
|
2004-06-17 17:51:17 +00:00
|
|
|
.Sh RETURN VALUES
|
2004-02-19 13:51:52 +00:00
|
|
|
If successful,
|
|
|
|
both
|
|
|
|
.Fn pthread_barrier_destroy
|
|
|
|
and
|
|
|
|
.Fn pthread_barrier_init
|
|
|
|
will return zero.
|
2004-06-17 17:51:17 +00:00
|
|
|
Otherwise, an error number will be returned to indicate the error.
|
2004-02-19 13:51:52 +00:00
|
|
|
If the call to
|
|
|
|
.Fn pthread_barrier_wait
|
2004-06-17 17:51:17 +00:00
|
|
|
is successful, all but one of the threads will return zero.
|
|
|
|
That one thread will return
|
|
|
|
.Dv PTHREAD_BARRIER_SERIAL_THREAD .
|
|
|
|
Otherwise, an error number will be returned to indicate the error.
|
2004-02-19 13:51:52 +00:00
|
|
|
.Pp
|
2004-06-17 17:51:17 +00:00
|
|
|
None of these functions will return
|
|
|
|
.Er EINTR .
|
2004-02-19 13:51:52 +00:00
|
|
|
.Sh ERRORS
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_destroy
|
|
|
|
function will fail if:
|
|
|
|
.Bl -tag -width Er
|
|
|
|
.It Bq Er EBUSY
|
|
|
|
An attempt was made to destroy
|
|
|
|
.Fa barrier
|
|
|
|
while it was in use.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_destroy
|
|
|
|
and
|
|
|
|
.Fn pthread_barrier_wait
|
|
|
|
functions may fail if:
|
|
|
|
.Bl -tag -width Er
|
|
|
|
.It Bq Er EINVAL
|
|
|
|
The value specified by
|
|
|
|
.Fa barrier
|
|
|
|
is invalid.
|
|
|
|
.El
|
|
|
|
.Pp
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_init
|
|
|
|
function will fail if:
|
|
|
|
.Bl -tag -width Er
|
|
|
|
.It Bq Er EAGAIN
|
|
|
|
The system lacks resources,
|
|
|
|
other than memory,
|
|
|
|
to initialize
|
|
|
|
.Fa barrier .
|
|
|
|
.It Bq Er EINVAL
|
|
|
|
The
|
|
|
|
.Fa count
|
|
|
|
argument is less than 1.
|
|
|
|
.It Bq Er ENOMEM
|
|
|
|
Insufficient memory to initialize
|
|
|
|
.Fa barrier .
|
|
|
|
.El
|
|
|
|
.Sh SEE ALSO
|
|
|
|
.Xr pthread_barrierattr 3
|
|
|
|
.Sh HISTORY
|
|
|
|
The
|
|
|
|
.Fn pthread_barrier_destroy ,
|
|
|
|
.Fn pthread_barrier_init
|
|
|
|
and
|
|
|
|
.Fn pthread_barrier_wait
|
|
|
|
functions first appeared in
|
2007-10-22 10:08:01 +00:00
|
|
|
.Lb libkse
|
2004-02-19 13:51:52 +00:00
|
|
|
in
|
|
|
|
.Fx 5.2 ,
|
|
|
|
and in
|
|
|
|
.Lb libthr
|
|
|
|
in
|
|
|
|
.Fx 5.3 .
|