248 lines
11 KiB
Groff
248 lines
11 KiB
Groff
.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by John Birrell.
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.\" 4. Neither the name of the author nor the names of any co-contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $Id: pthread.3,v 1.6 1998/04/10 09:33:09 jb Exp $
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.\"
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.Dd September 10, 1998
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.Dt PTHREAD 3
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.Os BSD 4
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.Sh NAME
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.Nm pthread
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.Nd POSIX thread functions
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.Sh DESCRIPTION
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POSIX threads are a set of functions that support applications with
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requirements for multiple flows of control, called
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.Fa threads ,
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within a process. Multithreading is used to improve the performance of a
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program.
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.Pp
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The POSIX thread functions are summarized in this section in the following
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groups:
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.Bl -bullet -offset indent
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.It
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Thread Routines
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.It
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Attribute Object Routines
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.It
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Mutex Routines
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.It
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Condition Variable Routines
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.It
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Read/Write Lock Routines
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.It
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Per-Thread Context Routines
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.It
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Cleanup Routines
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.El
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.Sh THREAD ROUTINES
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.Bl -tag -width Er
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.It int Fn pthread_create "pthread_t *thread" "const pthread_attr_t *attr" "void *(*start_routine)(void *)" "void *arg"
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Creates a new thread of execution.
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.It int Fn pthread_detach "pthread_t thread"
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Marks a thread for deletion.
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.It int Fn pthread_equal "pthread_t t1" "pthread_t t2"
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Compares two thread IDs.
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.It void Fn pthread_exit "void *value_ptr"
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Terminates the calling thread.
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.It int Fn pthread_join "pthread_t thread" "void **value_ptr"
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Causes the calling thread to wait for the termination of the specified thread.
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.It int Fn pthread_once "pthread_once_t *once_control" "void (*init_routine)(void)"
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Calls an initialization routine once.
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.It pthread_t Fn pthread_self void
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Returns the thread ID of the calling thread.
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.El
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.Sh ATTRIBUTE OBJECT ROUTINES
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.Bl -tag -width Er
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.It int Fn pthread_attr_destroy "pthread_attr_t *attr"
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Destroy a thread attributes object.
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.It int Fn pthread_attr_getinheritsched "pthread_attr_t *attr" "int *inheritsched"
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Get the inherit scheduling attribute from a thread attributes object.
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.It int Fn pthread_attr_getschedparam "pthread_attr_t *attr" "struct sched_param *param"
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Get the scheduling parameter attribute from a thread attributes object.
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.It int Fn pthread_attr_getschedpolicy "pthread_attr_t *attr" "int *policy"
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Get the scheduling policy attribute from a thread attributes object.
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.It int Fn pthread_attr_getscope "pthread_attr_t *attr" "int *contentionscope"
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Get the contention scope attribute from a thread attributes object.
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.It int Fn pthread_attr_getstacksize "pthread_attr_t *attr" "size_t *stacksize"
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Get the stack size attribute from a thread attributes object.
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.It int Fn pthread_attr_getstackaddr "pthread_attr_t *attr" "void **stackaddr"
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Get the stack address attribute from a thread attributes object.
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.It int Fn pthread_attr_getdetachstate "pthread_attr_t *attr" "int *detachstate"
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Get the detach state attribute from a thread attributes object.
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.It int Fn pthread_attr_init "pthread_attr_t *attr"
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Initialize a thread attributes object with default values.
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.It int Fn pthread_attr_setinheritsched "pthread_attr_t *attr" "int inheritsched"
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Set the inherit scheduling attribute in a thread attributes object.
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.It int Fn pthread_attr_setschedparam "pthread_attr_t *attr" "struct sched_param *param"
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Set the scheduling parameter attribute in a thread attributes object.
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.It int Fn pthread_attr_setschedpolicy "pthread_attr_t *attr" "int policy"
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Set the scheduling policy attribute in a thread attributes object.
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.It int Fn pthread_attr_setscope "pthread_attr_t *attr" "int contentionscope"
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Set the contention scope attribute in a thread attributes object.
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.It int Fn pthread_attr_setstacksize "pthread_attr_t *attr" "size_t stacksize"
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Set the stack size attribute in a thread attributes object.
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.It int Fn pthread_attr_setstackaddr "pthread_attr_t *attr" "void *stackaddr"
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Set the stack address attribute in a thread attributes object.
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.It int Fn pthread_attr_setdetachstate "pthread_attr_t *attr" "int detachstate"
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Set the detach state in a thread attributes object.
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.El
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.Sh MUTEX ROUTINES
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.Bl -tag -width Er
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.It int Fn pthread_mutexattr_destroy "pthread_mutexattr_t *attr"
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Destroy a mutex attributes object.
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.It int Fn pthread_mutexattr_init "pthread_mutexattr_t *attr"
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Initialize a mutex attributes object with default values.
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.It int Fn pthread_mutex_destroy "pthread_mutex_t *mutex"
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Destroy a mutex.
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.It int Fn pthread_mutex_init "pthread_mutex_t *mutex" "const pthread_mutexattr_t *attr"
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Initialize a mutex with specified attributes.
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.It int Fn pthread_mutex_lock "pthread_mutex_t *mutex"
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Lock a mutex and block until it becomes available.
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.It int Fn pthread_mutex_trylock "pthread_mutex_t *mutex"
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Try to lock a mutex, but don't block if the mutex is locked by another thread,
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including the current thread.
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.It int Fn pthread_mutex_unlock "pthread_mutex_t *mutex"
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Unlock a mutex.
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.El
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.Sh CONDITION VARIABLE ROUTINES
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.Bl -tag -width Er
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.It int Fn pthread_condattr_init "pthread_condattr_t *attr"
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Initialize a condition variable attributes object with default values.
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.It int Fn pthread_condattr_destroy "pthread_condattr_t *attr"
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Destroy a condition variable attributes object.
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.It int Fn pthread_cond_broadcast "pthread_cond_t *cond"
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Unblock all threads currently blocked on the specified condition variable.
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.It int Fn pthread_cond_destroy "pthread_cond_t *cond"
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Destroy a condition variable.
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.It int Fn pthread_cond_init "pthread_cond_t *cond" "const pthread_condattr_t *attr"
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Initialize a condition variable with specified attributes.
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.It int Fn pthread_cond_signal "pthread_cond_t *cond"
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Unblock at least one of the threads blocked on the specified condition variable.
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.It int Fn pthread_cond_timedwait "pthread_cond_t *cond" "pthread_mutex_t *mutex" "const struct timespec *abstime"
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Wait no longer than the specified time for a condition and lock the specified mutex.
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.It int Fn pthread_cond_wait "pthread_cond_t *" "pthread_mutex_t *mutex"
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Wait for a condition and lock the specified mutex.
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.El
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.Sh READ/WRITE LOCK ROUTINES
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.Bl -tag -width Er
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.It int Fn pthread_rwlock_destroy "pthread_rwlock_t *lock"
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Destroy a read/write lock object.
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.It int Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr"
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Initialize a read/write lock object.
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.It int Fn pthread_rwlock_rdlock "pthread_rwlock_t *lock"
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Lock a read/write lock for reading, blocking until the lock can be
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acquired.
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.It int Fn pthread_rwlock_tryrdlock "pthread_rwlock_t *lock"
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Attempt to lock a read/write lock for reading, without blocking if the
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lock is unavailable.
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.It int Fn pthread_rwlock_trywrlock "pthread_rwlock_t *lock"
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Attempt to lock a read/write lock for writing, without blocking if the
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lock is unavailable.
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.It int Fn pthread_rwlock_unlock "pthread_rwlock_t *lock"
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Unlock a read/write lock.
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.It int Fn pthread_rwlock_wrlock "pthread_rwlock_t *lock"
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Lock a read/write lock for writing, blocking until the lock can be
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acquired.
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.It int Fn pthread_rwlockattr_destroy "pthread_rwlockattr_t *attr"
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Destroy a read/write lock attribute object.
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.It int Fn pthread_rwlockattr_getpshared "pthread_rwlockattr_t *attr" "int *pshared"
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Retrieve the process shared setting for the read/write lock attribute
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object.
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.It int Fn pthread_rwlockattr_init "pthread_rwlockattr_t *attr"
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Initialize a read/write lock attribute object.
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.It int Fn pthread_rwlockattr_setpshared "pthread_rwlockattr_t *attr" "int *pshared"
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Set the process shared setting for the read/write lock attribute object.
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.El
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.Sh PER-THREAD CONTEXT ROUTINES
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.Bl -tag -width Er
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.It int Fn pthread_key_create "pthread_key_t *key" "void (*routine)(void *)"
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Create a thread-specific data key.
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.It int Fn pthread_key_delete "pthread_key_t key"
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Delete a thread-specific data key.
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.It void * Fn pthread_getspecific "pthread_key_t key" "void **value_ptr"
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Get the thread-specific value for the specified key.
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.It int Fn pthread_setspecific "pthread_key_t key" "const void *value_ptr"
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Set the thread-specific value for the specified key.
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.El
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.Sh CLEANUP ROUTINES
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.Bl -tag -width Er
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.It void Fn pthread_cleanup_pop "int execute"
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Remove the routine at the top of the calling thread's cancellation cleanup
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stack and optionally invoke it.
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.It void Fn pthread_cleanup_push "void (*routine)(void *)" "void *routine_arg"
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Push the specified cancellation cleanup handler onto the calling thread's
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cancellation stack.
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.El
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.Sh INSTALLATION
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The current FreeBSD POSIX thread implementation is built in the library
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.Fa libc_r
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which contains both thread-safe libc functions and the thread functions.
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This library replaces
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.Fa libc
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for threaded applications.
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.Pp
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By default,
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.Fa libc_r
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is built as part of a 'make world'. To disable the build of
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.Fa libc_r
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you must supply the '-DNOLIBC_R' option to
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.Xr make 1 .
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.Pp
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A FreeBSD specific option has been added to gcc to make linking
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threaded processes simple.
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.Fa gcc -pthread
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links a threaded process against
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.Fa libc_r
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instead of
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.Fa libc.
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.Sh STANDARDS
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The functions in
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.Fa libc_r
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with the
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.Fa pthread_
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prefix and not
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.Fa _np
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suffix or
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.Fa pthread_rwlock
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prefix conform to IEEE
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.Pq Dq Tn POSIX
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Std 1003.1 Second Edition 1996-07-12
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.Pp
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The functions in libc_r with the
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.Fa pthread_
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prefix and
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.Fa _np
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suffix are non-portable extensions to POSIX threads.
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.Pp
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The functions in libc_r with the
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.Fa pthread_rwlock
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prefix are extensions created by The Open Group as part of the Single
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UNIX Specification, Version 2.
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