.\" $NetBSD: pthread_barrier.3,v 1.8 2017/10/22 16:15:02 abhinav Exp $ .\" .\" Copyright (c) 2002, 2010 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. .\" .\" 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 .\" 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 October 22, 2017 .Dt PTHREAD_BARRIER 3 .Os .Sh NAME .Nm pthread_barrier , .Nm pthread_barrier_init , .Nm pthread_barrier_destroy , .Nm pthread_barrier_wait .Nd barrier interface .Sh LIBRARY .Lb libpthread .Sh SYNOPSIS .In pthread.h .Ft int .Fn pthread_barrier_init "pthread_barrier_t * restrict barrier" \ "const pthread_barrierattr_t * restrict attr" "unsigned int count" .Ft int .Fn pthread_barrier_destroy "pthread_barrier_t *barrier" .Ft int .Fn pthread_barrier_wait "pthread_barrier_t *barrier" .\" ---------------------------------------------------------------------------- .Sh DESCRIPTION The .Fn pthread_barrier_init function creates a new barrier with attributes .Fa attr and .Fa count . The .Fa count parameter indicates the number of threads which will participate in the barrier. The .Xr pthread_barrierattr_init 3 function may be used to specify the attributes supplied in .Fa attr . If .Fa attr is .Dv NULL , the default attributes are used. Barriers are most commonly used in the decomposition of parallel loops. .Pp .\" ----- The .Fn pthread_barrier_destroy function causes the resources allocated to .Fa barrier to be released. No threads should be blocked on .Fa barrier . .Pp .\" ----- The .Fn pthread_barrier_wait function causes the current thread to wait on the barrier specified. Once as many threads as specified by the .Fa count parameter to the corresponding .Fn pthread_barrier_init call have called .Fn pthread_barrier_wait , all threads will wake up, return from their respective .Fn pthread_barrier_wait calls and continue execution. .\" ----- .\" ---------------------------------------------------------------------------- .Sh RETURN VALUES If successful, .Fn pthread_barrier_init will return zero and put the new barrier id into .Fa barrier , otherwise an error number will be returned to indicate the error. .Pp .\" ----- If successful, .Fn pthread_barrier_destroy will return zero. Otherwise an error value will be returned. .Pp .\" ----- If successful, .Fn pthread_barrier_wait will return zero for all waiting threads except for one. One thread will receive status .Dv PTHREAD_BARRIER_SERIAL_THREAD , which is intended to indicate that this thread may be used to update shared data. It is the responsibility of this thread to insure the visibility and atomicity of any updates to shared data with respect to the other threads participating in the barrier. In the case of failure, an error value will be returned. .\" ---------------------------------------------------------------------------- .Sh ERRORS The .Fn pthread_barrier_init function may fail if: .Bl -tag -width Er .It Bq Er EINVAL The value specified by .Fa count is zero or .Fa attr is invalid. .El .Pp .\" ----- The .Fn pthread_barrier_destroy function may fail if: .Bl -tag -width Er .It Bq Er EBUSY The .Fa barrier still has active threads associated with it. .It Bq Er EINVAL The value specified by .Fa barrier is invalid. .El .Pp .\" ----- The .Fn pthread_barrier_wait function may fail if: .Bl -tag -width Er .It Bq Er EINVAL The value specified by .Fa barrier is invalid. .El .\" --------------------------------------------------------------------------- .Sh SEE ALSO .Xr pthread_barrierattr 3 , .Xr pthread_cond 3 , .Xr pthread_mutex 3 .Sh STANDARDS These functions conform to .St -p1003.1-2001 . s/compat/linux/arch/mips/linux_machdep.c?h=lockdoc-9.3&id=284c2b9aef087ed04fa805f7b7df95b8208eda76'>Merge proc::p_mutex and proc::p_smutex into a single adaptive mutex, sincead 2008-01-08In linux_sys_sysmips(), remove redundant kauth(9) call for LINUX_SETNAMEelad 2007-12-20Convert all the system call entry points from:dsl 2007-12-08ANSIfy most of the function definitions in sys/compat (but not ndis).dsl 2007-11-08Replace strncpy with strlcpy in compat linux and linux32 uname,njoly 2007-10-19machine/{bus,cpu,intr}.h -> sys/{bus,cpu,intr}.had 2007-06-13cleanup some bitrot; from Matthew Orgasschristos 2007-03-04Kill caddr_t; there will be some MI fallout, but it will be fixed shortly.christos 2007-02-09Merge newlock2 to head.ad 2007-01-04Consistent usage of KAUTH_GENERIC_ISSUSER.elad 2006-07-23Use the LWP cached credentials where sane.ad 2006-05-15include kauth.h for kauth_authorize_generic.yamt 2006-05-14integrate kauth.elad 2005-12-11merge ktrace-lwp.christos 2005-05-20Define linux_usertrap function, and set it in struct emul. For allfvdl 2005-02-26nuke trailing whitespaceperry 2004-06-19Build COMPAT_LINUX again on mips after the siginfo change.manu 2003-12-04Dynamic sysctl.atatat 2003-09-26Fix "constify sendsig/trapsignal" fallout for non-siginfo'd archs. Testsimonb 2003-08-02use copyin()/copyout() instead of fubyte()/subyte()jdolecek 2003-01-18Merge the nathanw_sa branch.thorpej