1 .\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
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33 .Dd September 10, 1998
38 .Nd POSIX thread functions
40 POSIX threads are a set of functions that support applications with
41 requirements for multiple flows of control, called
43 within a process. Multithreading is used to improve the performance of a
46 The POSIX thread functions are summarized in this section in the following
48 .Bl -bullet -offset indent
52 Attribute Object Routines
56 Condition Variable Routines
58 Read/Write Lock Routines
60 Per-Thread Context Routines
66 .It int Fn pthread_create "pthread_t *thread" "const pthread_attr_t *attr" "void *(*start_routine)(void *)" "void *arg"
67 Creates a new thread of execution.
68 .It int Fn pthread_detach "pthread_t thread"
69 Marks a thread for deletion.
70 .It int Fn pthread_equal "pthread_t t1" "pthread_t t2"
71 Compares two thread IDs.
72 .It void Fn pthread_exit "void *value_ptr"
73 Terminates the calling thread.
74 .It int Fn pthread_join "pthread_t thread" "void **value_ptr"
75 Causes the calling thread to wait for the termination of the specified thread.
76 .It int Fn pthread_cancel "pthread_t thread"
77 Cancels execution of a thread.
78 .It int Fn pthread_once "pthread_once_t *once_control" "void (*init_routine)(void)"
79 Calls an initialization routine once.
80 .It pthread_t Fn pthread_self void
81 Returns the thread ID of the calling thread.
83 .Sh ATTRIBUTE OBJECT ROUTINES
85 .It int Fn pthread_attr_destroy "pthread_attr_t *attr"
86 Destroy a thread attributes object.
87 .It int Fn pthread_attr_getinheritsched "pthread_attr_t *attr" "int *inheritsched"
88 Get the inherit scheduling attribute from a thread attributes object.
89 .It int Fn pthread_attr_getschedparam "pthread_attr_t *attr" "struct sched_param *param"
90 Get the scheduling parameter attribute from a thread attributes object.
91 .It int Fn pthread_attr_getschedpolicy "pthread_attr_t *attr" "int *policy"
92 Get the scheduling policy attribute from a thread attributes object.
93 .It int Fn pthread_attr_getscope "pthread_attr_t *attr" "int *contentionscope"
94 Get the contention scope attribute from a thread attributes object.
95 .It int Fn pthread_attr_getstacksize "pthread_attr_t *attr" "size_t *stacksize"
96 Get the stack size attribute from a thread attributes object.
97 .It int Fn pthread_attr_getstackaddr "pthread_attr_t *attr" "void **stackaddr"
98 Get the stack address attribute from a thread attributes object.
99 .It int Fn pthread_attr_getdetachstate "pthread_attr_t *attr" "int *detachstate"
100 Get the detach state attribute from a thread attributes object.
101 .It int Fn pthread_attr_init "pthread_attr_t *attr"
102 Initialize a thread attributes object with default values.
103 .It int Fn pthread_attr_setinheritsched "pthread_attr_t *attr" "int inheritsched"
104 Set the inherit scheduling attribute in a thread attributes object.
105 .It int Fn pthread_attr_setschedparam "pthread_attr_t *attr" "struct sched_param *param"
106 Set the scheduling parameter attribute in a thread attributes object.
107 .It int Fn pthread_attr_setschedpolicy "pthread_attr_t *attr" "int policy"
108 Set the scheduling policy attribute in a thread attributes object.
109 .It int Fn pthread_attr_setscope "pthread_attr_t *attr" "int contentionscope"
110 Set the contention scope attribute in a thread attributes object.
111 .It int Fn pthread_attr_setstacksize "pthread_attr_t *attr" "size_t stacksize"
112 Set the stack size attribute in a thread attributes object.
113 .It int Fn pthread_attr_setstackaddr "pthread_attr_t *attr" "void *stackaddr"
114 Set the stack address attribute in a thread attributes object.
115 .It int Fn pthread_attr_setdetachstate "pthread_attr_t *attr" "int detachstate"
116 Set the detach state in a thread attributes object.
120 .It int Fn pthread_mutexattr_destroy "pthread_mutexattr_t *attr"
121 Destroy a mutex attributes object.
122 .It int Fn pthread_mutexattr_init "pthread_mutexattr_t *attr"
123 Initialize a mutex attributes object with default values.
124 .It int Fn pthread_mutex_destroy "pthread_mutex_t *mutex"
126 .It int Fn pthread_mutex_init "pthread_mutex_t *mutex" "const pthread_mutexattr_t *attr"
127 Initialize a mutex with specified attributes.
128 .It int Fn pthread_mutex_lock "pthread_mutex_t *mutex"
129 Lock a mutex and block until it becomes available.
130 .It int Fn pthread_mutex_trylock "pthread_mutex_t *mutex"
131 Try to lock a mutex, but don't block if the mutex is locked by another thread,
132 including the current thread.
133 .It int Fn pthread_mutex_unlock "pthread_mutex_t *mutex"
136 .Sh CONDITION VARIABLE ROUTINES
138 .It int Fn pthread_condattr_init "pthread_condattr_t *attr"
139 Initialize a condition variable attributes object with default values.
140 .It int Fn pthread_condattr_destroy "pthread_condattr_t *attr"
141 Destroy a condition variable attributes object.
142 .It int Fn pthread_cond_broadcast "pthread_cond_t *cond"
143 Unblock all threads currently blocked on the specified condition variable.
144 .It int Fn pthread_cond_destroy "pthread_cond_t *cond"
145 Destroy a condition variable.
146 .It int Fn pthread_cond_init "pthread_cond_t *cond" "const pthread_condattr_t *attr"
147 Initialize a condition variable with specified attributes.
148 .It int Fn pthread_cond_signal "pthread_cond_t *cond"
149 Unblock 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"
151 Wait 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"
153 Wait for a condition and lock the specified mutex.
155 .Sh READ/WRITE LOCK ROUTINES
157 .It int Fn pthread_rwlock_destroy "pthread_rwlock_t *lock"
158 Destroy a read/write lock object.
159 .It int Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr"
160 Initialize a read/write lock object.
161 .It int Fn pthread_rwlock_rdlock "pthread_rwlock_t *lock"
162 Lock a read/write lock for reading, blocking until the lock can be
164 .It int Fn pthread_rwlock_tryrdlock "pthread_rwlock_t *lock"
165 Attempt to lock a read/write lock for reading, without blocking if the
167 .It int Fn pthread_rwlock_trywrlock "pthread_rwlock_t *lock"
168 Attempt to lock a read/write lock for writing, without blocking if the
170 .It int Fn pthread_rwlock_unlock "pthread_rwlock_t *lock"
171 Unlock a read/write lock.
172 .It int Fn pthread_rwlock_wrlock "pthread_rwlock_t *lock"
173 Lock a read/write lock for writing, blocking until the lock can be
175 .It int Fn pthread_rwlockattr_destroy "pthread_rwlockattr_t *attr"
176 Destroy a read/write lock attribute object.
177 .It int Fn pthread_rwlockattr_getpshared "pthread_rwlockattr_t *attr" "int *pshared"
178 Retrieve the process shared setting for the read/write lock attribute
180 .It int Fn pthread_rwlockattr_init "pthread_rwlockattr_t *attr"
181 Initialize a read/write lock attribute object.
182 .It int Fn pthread_rwlockattr_setpshared "pthread_rwlockattr_t *attr" "int *pshared"
183 Set the process shared setting for the read/write lock attribute object.
185 .Sh PER-THREAD CONTEXT ROUTINES
187 .It int Fn pthread_key_create "pthread_key_t *key" "void (*routine)(void *)"
188 Create a thread-specific data key.
189 .It int Fn pthread_key_delete "pthread_key_t key"
190 Delete a thread-specific data key.
191 .It void * Fn pthread_getspecific "pthread_key_t key" "void **value_ptr"
192 Get the thread-specific value for the specified key.
193 .It int Fn pthread_setspecific "pthread_key_t key" "const void *value_ptr"
194 Set the thread-specific value for the specified key.
198 .It void Fn pthread_cleanup_pop "int execute"
199 Remove the routine at the top of the calling thread's cancellation cleanup
200 stack and optionally invoke it.
201 .It void Fn pthread_cleanup_push "void (*routine)(void *)" "void *routine_arg"
202 Push the specified cancellation cleanup handler onto the calling thread's
206 The current FreeBSD POSIX thread implementation is built in the library
208 which contains both thread-safe libc functions and the thread functions.
209 This library replaces
211 for threaded applications.
215 is built as part of a 'make world'. To disable the build of
217 you must supply the '-DNOLIBC_R' option to
220 A FreeBSD specific option has been added to gcc to make linking
221 threaded processes simple.
223 links a threaded process against
236 prefix conform to IEEE
238 Std 1003.1 Second Edition 1996-07-12
240 The functions in libc_r with the
244 suffix are non-portable extensions to POSIX threads.
246 The functions in libc_r with the
248 prefix are extensions created by The Open Group as part of the Single
249 UNIX Specification, Version 2.