1.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>. 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.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by John Birrell. 15.\" 4. Neither the name of the author nor the names of any co-contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" $FreeBSD$ 32.\" 33.Dd September 10, 1998 34.Dt PTHREAD 3 35.Os BSD 4 36.Sh NAME 37.Nm pthread 38.Nd POSIX thread functions 39.Sh DESCRIPTION 40POSIX threads are a set of functions that support applications with 41requirements for multiple flows of control, called 42.Fa threads , 43within a process. Multithreading is used to improve the performance of a 44program. 45.Pp 46The POSIX thread functions are summarized in this section in the following 47groups: 48.Bl -bullet -offset indent 49.It 50Thread Routines 51.It 52Attribute Object Routines 53.It 54Mutex Routines 55.It 56Condition Variable Routines 57.It 58Read/Write Lock Routines 59.It 60Per-Thread Context Routines 61.It 62Cleanup Routines 63.El 64.Sh THREAD ROUTINES 65.Bl -tag -width Er 66.It int Fn pthread_create "pthread_t *thread" "const pthread_attr_t *attr" "void *(*start_routine)(void *)" "void *arg" 67Creates a new thread of execution. 68.It int Fn pthread_detach "pthread_t thread" 69Marks a thread for deletion. 70.It int Fn pthread_equal "pthread_t t1" "pthread_t t2" 71Compares two thread IDs. 72.It void Fn pthread_exit "void *value_ptr" 73Terminates the calling thread. 74.It int Fn pthread_join "pthread_t thread" "void **value_ptr" 75Causes the calling thread to wait for the termination of the specified thread. 76.It int Fn pthread_cancel "pthread_t thread" 77Cancels execution of a thread. 78.It int Fn pthread_once "pthread_once_t *once_control" "void (*init_routine)(void)" 79Calls an initialization routine once. 80.It pthread_t Fn pthread_self void 81Returns the thread ID of the calling thread. 82.El 83.Sh ATTRIBUTE OBJECT ROUTINES 84.Bl -tag -width Er 85.It int Fn pthread_attr_destroy "pthread_attr_t *attr" 86Destroy a thread attributes object. 87.It int Fn pthread_attr_getinheritsched "pthread_attr_t *attr" "int *inheritsched" 88Get the inherit scheduling attribute from a thread attributes object. 89.It int Fn pthread_attr_getschedparam "pthread_attr_t *attr" "struct sched_param *param" 90Get the scheduling parameter attribute from a thread attributes object. 91.It int Fn pthread_attr_getschedpolicy "pthread_attr_t *attr" "int *policy" 92Get the scheduling policy attribute from a thread attributes object. 93.It int Fn pthread_attr_getscope "pthread_attr_t *attr" "int *contentionscope" 94Get the contention scope attribute from a thread attributes object. 95.It int Fn pthread_attr_getstacksize "pthread_attr_t *attr" "size_t *stacksize" 96Get the stack size attribute from a thread attributes object. 97.It int Fn pthread_attr_getstackaddr "pthread_attr_t *attr" "void **stackaddr" 98Get the stack address attribute from a thread attributes object. 99.It int Fn pthread_attr_getdetachstate "pthread_attr_t *attr" "int *detachstate" 100Get the detach state attribute from a thread attributes object. 101.It int Fn pthread_attr_init "pthread_attr_t *attr" 102Initialize a thread attributes object with default values. 103.It int Fn pthread_attr_setinheritsched "pthread_attr_t *attr" "int inheritsched" 104Set the inherit scheduling attribute in a thread attributes object. 105.It int Fn pthread_attr_setschedparam "pthread_attr_t *attr" "struct sched_param *param" 106Set the scheduling parameter attribute in a thread attributes object. 107.It int Fn pthread_attr_setschedpolicy "pthread_attr_t *attr" "int policy" 108Set the scheduling policy attribute in a thread attributes object. 109.It int Fn pthread_attr_setscope "pthread_attr_t *attr" "int contentionscope" 110Set the contention scope attribute in a thread attributes object. 111.It int Fn pthread_attr_setstacksize "pthread_attr_t *attr" "size_t stacksize" 112Set the stack size attribute in a thread attributes object. 113.It int Fn pthread_attr_setstackaddr "pthread_attr_t *attr" "void *stackaddr" 114Set the stack address attribute in a thread attributes object. 115.It int Fn pthread_attr_setdetachstate "pthread_attr_t *attr" "int detachstate" 116Set the detach state in a thread attributes object. 117.El 118.Sh MUTEX ROUTINES 119.Bl -tag -width Er 120.It int Fn pthread_mutexattr_destroy "pthread_mutexattr_t *attr" 121Destroy a mutex attributes object. 122.It int Fn pthread_mutexattr_init "pthread_mutexattr_t *attr" 123Initialize a mutex attributes object with default values. 124.It int Fn pthread_mutex_destroy "pthread_mutex_t *mutex" 125Destroy a mutex. 126.It int Fn pthread_mutex_init "pthread_mutex_t *mutex" "const pthread_mutexattr_t *attr" 127Initialize a mutex with specified attributes. 128.It int Fn pthread_mutex_lock "pthread_mutex_t *mutex" 129Lock a mutex and block until it becomes available. 130.It int Fn pthread_mutex_trylock "pthread_mutex_t *mutex" 131Try to lock a mutex, but don't block if the mutex is locked by another thread, 132including the current thread. 133.It int Fn pthread_mutex_unlock "pthread_mutex_t *mutex" 134Unlock a mutex. 135.El 136.Sh CONDITION VARIABLE ROUTINES 137.Bl -tag -width Er 138.It int Fn pthread_condattr_init "pthread_condattr_t *attr" 139Initialize a condition variable attributes object with default values. 140.It int Fn pthread_condattr_destroy "pthread_condattr_t *attr" 141Destroy a condition variable attributes object. 142.It int Fn pthread_cond_broadcast "pthread_cond_t *cond" 143Unblock all threads currently blocked on the specified condition variable. 144.It int Fn pthread_cond_destroy "pthread_cond_t *cond" 145Destroy a condition variable. 146.It int Fn pthread_cond_init "pthread_cond_t *cond" "const pthread_condattr_t *attr" 147Initialize a condition variable with specified attributes. 148.It int Fn pthread_cond_signal "pthread_cond_t *cond" 149Unblock at least one of the threads blocked on the specified condition variable. 150.It int Fn pthread_cond_timedwait "pthread_cond_t *cond" "pthread_mutex_t *mutex" "const struct timespec *abstime" 151Wait no longer than the specified time for a condition and lock the specified mutex. 152.It int Fn pthread_cond_wait "pthread_cond_t *" "pthread_mutex_t *mutex" 153Wait for a condition and lock the specified mutex. 154.El 155.Sh READ/WRITE LOCK ROUTINES 156.Bl -tag -width Er 157.It int Fn pthread_rwlock_destroy "pthread_rwlock_t *lock" 158Destroy a read/write lock object. 159.It int Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr" 160Initialize a read/write lock object. 161.It int Fn pthread_rwlock_rdlock "pthread_rwlock_t *lock" 162Lock a read/write lock for reading, blocking until the lock can be 163acquired. 164.It int Fn pthread_rwlock_tryrdlock "pthread_rwlock_t *lock" 165Attempt to lock a read/write lock for reading, without blocking if the 166lock is unavailable. 167.It int Fn pthread_rwlock_trywrlock "pthread_rwlock_t *lock" 168Attempt to lock a read/write lock for writing, without blocking if the 169lock is unavailable. 170.It int Fn pthread_rwlock_unlock "pthread_rwlock_t *lock" 171Unlock a read/write lock. 172.It int Fn pthread_rwlock_wrlock "pthread_rwlock_t *lock" 173Lock a read/write lock for writing, blocking until the lock can be 174acquired. 175.It int Fn pthread_rwlockattr_destroy "pthread_rwlockattr_t *attr" 176Destroy a read/write lock attribute object. 177.It int Fn pthread_rwlockattr_getpshared "pthread_rwlockattr_t *attr" "int *pshared" 178Retrieve the process shared setting for the read/write lock attribute 179object. 180.It int Fn pthread_rwlockattr_init "pthread_rwlockattr_t *attr" 181Initialize a read/write lock attribute object. 182.It int Fn pthread_rwlockattr_setpshared "pthread_rwlockattr_t *attr" "int *pshared" 183Set the process shared setting for the read/write lock attribute object. 184.El 185.Sh PER-THREAD CONTEXT ROUTINES 186.Bl -tag -width Er 187.It int Fn pthread_key_create "pthread_key_t *key" "void (*routine)(void *)" 188Create a thread-specific data key. 189.It int Fn pthread_key_delete "pthread_key_t key" 190Delete a thread-specific data key. 191.It void * Fn pthread_getspecific "pthread_key_t key" "void **value_ptr" 192Get the thread-specific value for the specified key. 193.It int Fn pthread_setspecific "pthread_key_t key" "const void *value_ptr" 194Set the thread-specific value for the specified key. 195.El 196.Sh CLEANUP ROUTINES 197.Bl -tag -width Er 198.It void Fn pthread_cleanup_pop "int execute" 199Remove the routine at the top of the calling thread's cancellation cleanup 200stack and optionally invoke it. 201.It void Fn pthread_cleanup_push "void (*routine)(void *)" "void *routine_arg" 202Push the specified cancellation cleanup handler onto the calling thread's 203cancellation stack. 204.El 205.Sh INSTALLATION 206The current FreeBSD POSIX thread implementation is built in the library 207.Fa libc_r 208which contains both thread-safe libc functions and the thread functions. 209This library replaces 210.Fa libc 211for threaded applications. 212.Pp 213By default, 214.Fa libc_r 215is built as part of a 'make world'. To disable the build of 216.Fa libc_r 217you must supply the '-DNOLIBC_R' option to 218.Xr make 1 . 219.Pp 220A FreeBSD specific option has been added to gcc to make linking 221threaded processes simple. 222.Fa gcc -pthread 223links a threaded process against 224.Fa libc_r 225instead of 226.Fa libc. 227.Sh SEE ALSO 228.Xr pthread_create 3 , 229.Xr pthread_detach 3 , 230.Xr pthread_equal 3 , 231.Xr pthread_exit 3 , 232.Xr pthread_join 3 , 233.Xr pthread_once 3 , 234.Xr pthread_self 3 , 235.Xr pthread_mutex_destroy 3 , 236.Xr pthread_mutex_init 3 , 237.Xr pthread_mutex_lock 3 , 238.Xr pthread_mutex_trylock 3 , 239.Xr pthread_mutex_unlock 3 , 240.Xr pthread_cond_broadcast 3 , 241.Xr pthread_cond_destroy 3 , 242.Xr pthread_cond_init 3 , 243.Xr pthread_cond_signal 3 , 244.Xr pthread_cond_timedwait 3 , 245.Xr pthread_cond_wait 3 , 246.Xr pthread_rwlock_destroy 3 , 247.Xr pthread_rwlock_init 3 , 248.Xr pthread_rwlock_rdlock 3 , 249.Xr pthread_rwlock_unlock 3 , 250.Xr pthread_rwlock_wrlock 3 , 251.Xr pthread_rwlockattr_destroy 3 , 252.Xr pthread_rwlockattr_getpshared 3 , 253.Xr pthread_rwlockattr_init 3 , 254.Xr pthread_rwlockattr_setpshared 3 , 255.Xr pthread_key_delete 3 , 256.Xr pthread_getspecific 3 , 257.Xr pthread_setspecific 3 , 258.Xr pthread_cleanup_pop 3 , 259.Xr pthread_cleanup_push 3 260.Sh STANDARDS 261The functions in 262.Fa libc_r 263with the 264.Fa pthread_ 265prefix and not 266.Fa _np 267suffix or 268.Fa pthread_rwlock 269prefix conform to IEEE 270.Pq Dq Tn POSIX 271Std 1003.1 Second Edition 1996-07-12 272.Pp 273The functions in libc_r with the 274.Fa pthread_ 275prefix and 276.Fa _np 277suffix are non-portable extensions to POSIX threads. 278.Pp 279The functions in libc_r with the 280.Fa pthread_rwlock 281prefix are extensions created by The Open Group as part of the Single 282UNIX Specification, Version 2. 283