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PTHREAD(3) Library Functions Manual PTHREAD(3) NAME pthread -- POSIX thread functions LIBRARY POSIX Threads Library (libpthread, -lpthread) SYNOPSIS #include <pthread.h> DESCRIPTION POSIX threads are a set of functions that support applications with re- quirements for multiple flows of control, called threads, within a process. Multithreading is used to improve the performance of a program. The POSIX thread functions are summarized in this section in the following groups: * Thread Routines * Attribute Object Routines * Mutex Routines * Condition Variable Routines * Read/Write Lock Routines * Per-Thread Context Routines * Cleanup Routines FreeBSD extensions to the POSIX thread functions are summarized in pthread_np(3). Thread Routines int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg) Creates a new thread of execution. int pthread_cancel(pthread_t thread) Cancels execution of a thread. int pthread_detach(pthread_t thread) Marks a thread for deletion. int pthread_equal(pthread_t t1, pthread_t t2) Compares two thread IDs. void pthread_exit(void *value_ptr) Terminates the calling thread. int pthread_join(pthread_t thread, void **value_ptr) Causes the calling thread to wait for the termination of the speci- fied thread. int pthread_kill(pthread_t thread, int sig) Delivers a signal to a specified thread. int pthread_once(pthread_once_t *once_control, void (*init_routine)(void)) Calls an initialization routine once. pthread_t pthread_self(void) Returns the thread ID of the calling thread. int pthread_setcancelstate(int state, int *oldstate) Sets the current thread's cancelability state. int pthread_setcanceltype(int type, int *oldtype) Sets the current thread's cancelability type. void pthread_testcancel(void) Creates a cancellation point in the calling thread. void pthread_yield(void) Allows the scheduler to run another thread instead of the current one. Attribute Object Routines int pthread_attr_destroy(pthread_attr_t *attr) Destroy a thread attributes object. int pthread_attr_getinheritsched(const pthread_attr_t *attr, int *inher- itsched) Get the inherit scheduling attribute from a thread attributes ob- ject. int pthread_attr_getschedparam(const pthread_attr_t *attr, struct sched_param *param) Get the scheduling parameter attribute from a thread attributes ob- ject. int pthread_attr_getschedpolicy(const pthread_attr_t *attr, int *policy) Get the scheduling policy attribute from a thread attributes ob- ject. int pthread_attr_getscope(const pthread_attr_t *attr, int *contentionscope) Get the contention scope attribute from a thread attributes object. int pthread_attr_getstacksize(const pthread_attr_t *attr, size_t *stack- size) Get the stack size attribute from a thread attributes object. int pthread_attr_getstackaddr(const pthread_attr_t *attr, void **stackaddr) Get the stack address attribute from a thread attributes object. int pthread_attr_getdetachstate(const pthread_attr_t *attr, int *detach- state) Get the detach state attribute from a thread attributes object. int pthread_attr_init(pthread_attr_t *attr) Initialize a thread attributes object with default values. int pthread_attr_setinheritsched(pthread_attr_t *attr, int inheritsched) Set the inherit scheduling attribute in a thread attributes object. int pthread_attr_setschedparam(pthread_attr_t *attr, const struct sched_param *param) Set the scheduling parameter attribute in a thread attributes ob- ject. int pthread_attr_setschedpolicy(pthread_attr_t *attr, int policy) Set the scheduling policy attribute in a thread attributes object. int pthread_attr_setscope(pthread_attr_t *attr, int contentionscope) Set the contention scope attribute in a thread attributes object. int pthread_attr_setstacksize(pthread_attr_t *attr, size_t stacksize) Set the stack size attribute in a thread attributes object. int pthread_attr_setstackaddr(pthread_attr_t *attr, void *stackaddr) Set the stack address attribute in a thread attributes object. int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate) Set the detach state in a thread attributes object. Mutex Routines int pthread_mutexattr_destroy(pthread_mutexattr_t *attr) Destroy a mutex attributes object. int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *restrict attr, int *restrict ceiling) Obtain priority ceiling attribute of mutex attribute object. int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *restrict attr, int *restrict protocol) Obtain protocol attribute of mutex attribute object. int pthread_mutexattr_gettype(const pthread_mutexattr_t *restrict attr, int *restrict type) Obtain the mutex type attribute in the specified mutex attributes object. int pthread_mutexattr_init(pthread_mutexattr_t *attr) Initialize a mutex attributes object with default values. int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr, int ceil- ing) Set priority ceiling attribute of mutex attribute object. int pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr, int protocol) Set protocol attribute of mutex attribute object. int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type) Set the mutex type attribute that is used when a mutex is created. int pthread_mutex_destroy(pthread_mutex_t *mutex) Destroy a mutex. int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutex- attr_t *attr) Initialize a mutex with specified attributes. int pthread_mutex_lock(pthread_mutex_t *mutex) Lock a mutex and block until it becomes available. int pthread_mutex_timedlock(pthread_mutex_t *mutex, const struct time- spec *abstime) Lock a mutex and block until it becomes available or until the timeout expires. int pthread_mutex_trylock(pthread_mutex_t *mutex) Try to lock a mutex, but do not block if the mutex is locked by an- other thread, including the current thread. int pthread_mutex_unlock(pthread_mutex_t *mutex) Unlock a mutex. Condition Variable Routines int pthread_condattr_destroy(pthread_condattr_t *attr) Destroy a condition variable attributes object. int pthread_condattr_init(pthread_condattr_t *attr) Initialize a condition variable attributes object with default val- ues. int pthread_cond_broadcast(pthread_cond_t *cond) Unblock all threads currently blocked on the specified condition variable. int pthread_cond_destroy(pthread_cond_t *cond) Destroy a condition variable. int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr) Initialize a condition variable with specified attributes. int pthread_cond_signal(pthread_cond_t *cond) Unblock at least one of the threads blocked on the specified condi- tion variable. int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime) Unlock the specified mutex, wait no longer than the specified time for a condition, and then relock the mutex. int pthread_cond_wait(pthread_cond_t *, pthread_mutex_t *mutex) Unlock the specified mutex, wait for a condition, and relock the mutex. Read/Write Lock Routines int pthread_rwlock_destroy(pthread_rwlock_t *lock) Destroy a read/write lock object. int pthread_rwlock_init(pthread_rwlock_t *lock, const pthread_rwlock- attr_t *attr) Initialize a read/write lock object. int pthread_rwlock_rdlock(pthread_rwlock_t *lock) Lock a read/write lock for reading, blocking until the lock can be acquired. int pthread_rwlock_tryrdlock(pthread_rwlock_t *lock) Attempt to lock a read/write lock for reading, without blocking if the lock is unavailable. int pthread_rwlock_trywrlock(pthread_rwlock_t *lock) Attempt to lock a read/write lock for writing, without blocking if the lock is unavailable. int pthread_rwlock_unlock(pthread_rwlock_t *lock) Unlock a read/write lock. int pthread_rwlock_wrlock(pthread_rwlock_t *lock) Lock a read/write lock for writing, blocking until the lock can be acquired. int pthread_rwlockattr_destroy(pthread_rwlockattr_t *attr) Destroy a read/write lock attribute object. int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t *attr, int *pshared) Retrieve the process shared setting for the read/write lock at- tribute object. int pthread_rwlockattr_init(pthread_rwlockattr_t *attr) Initialize a read/write lock attribute object. int pthread_rwlockattr_setpshared(pthread_rwlockattr_t *attr, int pshared) Set the process shared setting for the read/write lock attribute object. Per-Thread Context Routines int pthread_key_create(pthread_key_t *key, void (*routine)(void *)) Create a thread-specific data key. int pthread_key_delete(pthread_key_t key) Delete a thread-specific data key. void * pthread_getspecific(pthread_key_t key) Get the thread-specific value for the specified key. int pthread_setspecific(pthread_key_t key, const void *value_ptr) Set the thread-specific value for the specified key. Cleanup Routines int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void)) Register fork handlers. void pthread_cleanup_pop(int execute) Remove the routine at the top of the calling thread's cancellation cleanup stack and optionally invoke it. void pthread_cleanup_push(void (*routine)(void *), void *routine_arg) Push the specified cancellation cleanup handler onto the calling thread's cancellation stack. IMPLEMENTATION NOTES The current FreeBSD POSIX thread implementation is built into the 1:1 Threading Library (libthr, -lthr) library. It contains thread-safe ver- sions of Standard C Library (libc, -lc) functions and the thread functions. Threaded applications are linked with this library. SEE ALSO libthr(3), pthread_atfork(3), pthread_attr(3), pthread_cancel(3), pthread_cleanup_pop(3), pthread_cleanup_push(3), pthread_cond_broadcast(3), pthread_cond_destroy(3), pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_timedwait(3), pthread_cond_wait(3), pthread_condattr_de- stroy(3), pthread_condattr_init(3), pthread_create(3), pthread_detach(3), pthread_equal(3), pthread_exit(3), pthread_getspecific(3), pthread_join(3), pthread_key_delete(3), pthread_kill(3), pthread_mutex_destroy(3), pthread_mutex_init(3), pthread_mutex_lock(3), pthread_mutex_trylock(3), pthread_mutex_unlock(3), pthread_mutexattr_destroy(3), pthread_mutex- attr_getprioceiling(3), pthread_mutexattr_getprotocol(3), pthread_mutex- attr_gettype(3), pthread_mutexattr_init(3), pthread_mutexattr_setprioceil- ing(3), pthread_mutexattr_setprotocol(3), pthread_mutexattr_settype(3), pthread_np(3), pthread_once(3), pthread_rwlock_destroy(3), pthread_rwlock_init(3), pthread_rwlock_rdlock(3), pthread_rwlock_unlock(3), pthread_rwlock_wrlock(3), pthread_rwlockattr_destroy(3), pthread_rwlock- attr_getpshared(3), pthread_rwlockattr_init(3), pthread_rwlockattr_setp- shared(3), pthread_self(3), pthread_setcancelstate(3), pthread_setcancel- type(3), pthread_setspecific(3), pthread_testcancel(3) STANDARDS The functions with the pthread_ prefix and not _np suffix or pthread_rwlock prefix conform to ISO/IEC 9945-1:1996 ("POSIX.1"). The functions with the pthread_ prefix and _np suffix are non-portable ex- tensions to POSIX threads. The functions with the pthread_rwlock prefix are extensions created by The Open Group as part of the Version 2 of the Single UNIX Specification ("SUSv2"). FreeBSD ports 15.quarterly October 12, 2021 PTHREAD(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | IMPLEMENTATION NOTES | SEE ALSO | STANDARDS
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