1.\" $NetBSD: pthread.3,v 1.18 2017/10/23 01:03:23 wiz Exp $ 2.\" 3.\" Copyright (c) 2003, 2007, 2009 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Hubert Feyrer <hubertf@NetBSD.org> and Thomas Klausner <wiz@NetBSD.org>. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd November 22, 2016 31.Dt PTHREAD 3 32.Os 33.Sh NAME 34.Nm pthread 35.Nd POSIX Threads Library 36.Sh LIBRARY 37.Lb libpthread 38.Sh SYNOPSIS 39.In pthread.h 40.Pp 41.Nm cc 42.Op Ar flags 43.Ar files 44.Fl lpthread 45.Op Ar libraries 46.Sh DESCRIPTION 47The 48.Nm 49library provides an implementation of the standard POSIX threads 50library. 51.Pp 52The 53.Nx 54implementation is based on 1:1 thread model, therefore each 55.Nm 56has a kernel thread, called a light-weight process (LWP). 57.Pp 58Note that the system private thread interfaces upon which the 59.Nm 60library is built are subject to change without notice. 61In order to remain compatible with future 62.Nx 63releases, programs must be linked against the dynamic version of the 64thread library. 65Statically linked programs using the POSIX 66threads framework may not work when run on a future version of the system. 67.Sh FUNCTIONS 68The following functions comprise the core of the 69.Nm 70library: 71.Bl -column -offset indent "pthread_barrier_destroy(3)" "XXX" 72.It Sy Function Ta Sy Description 73.It Xr pthread_attr 3 Ta thread attribute operations 74.It Xr pthread_barrier_destroy 3 Ta destroy a barrier 75.It Xr pthread_barrier_init 3 Ta create a barrier 76.It Xr pthread_barrier_wait 3 Ta wait for a barrier 77.It Xr pthread_barrierattr 3 Ta barrier attribute operations 78.It Xr pthread_cancel 3 Ta cancel the execution of a thread 79.It Xr pthread_cleanup_push 3 Ta add or remove cleanup functions 80.It Xr pthread_cond_broadcast 3 Ta unblock one or more threads 81.It Xr pthread_cond_destroy 3 Ta destroy a condition variable 82.It Xr pthread_cond_init 3 Ta create a condition variable 83.It Xr pthread_cond_wait 3 Ta wait for a condition variable 84.It Xr pthread_condattr 3 Ta condition attribute operations 85.It Xr pthread_create 3 Ta create a new thread 86.It Xr pthread_detach 3 Ta detach a thread 87.It Xr pthread_equal 3 Ta compare thread identifiers 88.It Xr pthread_exit 3 Ta terminate the calling thread 89.It Xr pthread_getspecific 3 Ta get a thread-specific data value 90.It Xr pthread_join 3 Ta wait for thread termination 91.It Xr pthread_key_create 3 Ta thread-specific data key creation 92.It Xr pthread_key_delete 3 Ta delete a thread-specific data key 93.It Xr pthread_kill 3 Ta send a signal to a specific thread 94.It Xr pthread_mutex_destroy 3 Ta free a mutex 95.It Xr pthread_mutex_init 3 Ta create a mutex 96.It Xr pthread_mutex_lock 3 Ta acquire a lock on a mutex 97.It Xr pthread_mutex_unlock 3 Ta unlock a mutex 98.It Xr pthread_mutexattr 3 Ta mutex attribute operations 99.It Xr pthread_once 3 Ta dynamic package initialization 100.It Xr pthread_rwlock_destroy 3 Ta destroy a read/write lock 101.It Xr pthread_rwlock_init 3 Ta initialize a read/write lock 102.It Xr pthread_rwlock_rdlock 3 Ta acquire a read/write lock for reading 103.It Xr pthread_rwlock_unlock 3 Ta release a read/write lock 104.It Xr pthread_rwlock_wrlock 3 Ta acquire a read/write lock for writing 105.It Xr pthread_rwlockattr 3 Ta read/write lock attribute operations 106.It Xr pthread_schedparam 3 Ta thread scheduling manipulation 107.It Xr pthread_self 3 Ta get the ID of the calling thread 108.It Xr pthread_setspecific 3 Ta get a thread-specific data value 109.It Xr pthread_sigmask 3 Ta manipulate a thread's signal mask 110.It Xr pthread_spin_destroy 3 Ta destroy a spin lock 111.It Xr pthread_spin_init 3 Ta initialize a spin lock 112.It Xr pthread_spin_lock 3 Ta acquire a spin lock 113.It Xr pthread_spin_unlock 3 Ta release a spin lock 114.It Xr pthread_testcancel 3 Ta set cancelability state 115.El 116.Sh ENVIRONMENT 117The following environment variables affect the behavior of the library: 118.Bl -tag -width "XXX" 119.It Ev PTHREAD_DIAGASSERT 120Possible values are any combinations of: 121.Pp 122.Bl -tag -width "X " -offset 1n -compact 123.It Em A 124Report errors to application by error return, but do not abort. 125.It Em a 126Abort on errors, creating a core dump for further debugging. 127.It Em E 128Do not log errors to stdout. 129.It Em e 130Log errors to stdout. 131.It Em L 132Do not log errors via 133.Xr syslogd 8 . 134.It Em l 135Log errors via 136.Xr syslogd 8 . 137.El 138.Pp 139If not set in the environment, the 140.Nm 141library behaves as if 142.Em AEL 143has been specified. 144.It Ev PTHREAD_STACKSIZE 145Integer value giving the stack size in kilobytes. 146This allows to set a smaller stack size than the default stack size. 147The default stack size is the current limit on the stack size as 148set with the shell's command to change limits 149.Ic ( limit 150for 151.Xr csh 1 , 152or 153.Ic ulimit 154for 155.Xr sh 1 ) . 156.El 157.Sh SEE ALSO 158.Rs 159.%A David R. Butenhof 160.%T Programming with POSIX(R) Threads 161.%D 1997 162.%I Addison-Wesley 163.Re 164.Sh STANDARDS 165The 166.Nm 167library conforms to 168.St -p1003.1-2001 . 169.Sh CAVEATS 170Due to limitations in the current pthread implementation, 171.Xr makecontext 3 172and 173.Xr sigaltstack 2 174should not be used in programs which link against the 175.Nm 176library (whether threads are used or not). 177