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PTHREAD(3) Library Functions Manual PTHREAD(3)

pthreadPOSIX thread functions

library “libpthread”

#include <pthread.h>

POSIX threads are a set of functions that support applications with requirements for multiple flows of control, called , 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:

int (pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg);
Creates a new thread of execution.
int (pthread_t thread)
Cancels execution of a thread.
int (pthread_t thread)
Marks a thread for deletion.
int (pthread_t t1, pthread_t t2)
Compares two thread IDs.
void (void *value_ptr)
Terminates the calling thread.
int (pthread_t thread, void **value_ptr)
Causes the calling thread to wait for the termination of the specified thread.
int (pthread_t thread, int sig)
Delivers a signal to a specified thread.
int (pthread_once_t *once_control, void (*init_routine)(void))
Calls an initialization routine once.
pthread_t (void)
Returns the thread ID of the calling thread.
int (int state, int *oldstate)
Sets the current thread's cancelability state.
int (int type, int *oldtype)
Sets the current thread's cancelability type.
void (void)
Creates a cancellation point in the calling thread.
void (void)
Allows the scheduler to run another thread instead of the current one.

int (pthread_attr_t *attr)
Destroy a thread attributes object.
int (const pthread_attr_t *attr, int *inheritsched);
Get the inherit scheduling attribute from a thread attributes object.
int (const pthread_attr_t *attr, struct sched_param *param);
Get the scheduling parameter attribute from a thread attributes object.
int (const pthread_attr_t *attr, int *policy)
Get the scheduling policy attribute from a thread attributes object.
int (const pthread_attr_t *attr, int *contentionscope)
Get the contention scope attribute from a thread attributes object.
int (const pthread_attr_t *attr, size_t *stacksize)
Get the stack size attribute from a thread attributes object.
int (const pthread_attr_t *attr, void **stackaddr)
Get the stack address attribute from a thread attributes object.
int (const pthread_attr_t *attr, int *detachstate)
Get the detach state attribute from a thread attributes object.
int (pthread_attr_t *attr)
Initialize a thread attributes object with default values.
int (pthread_attr_t *attr, int inheritsched)
Set the inherit scheduling attribute in a thread attributes object.
int (pthread_attr_t *attr, const struct sched_param *param);
Set the scheduling parameter attribute in a thread attributes object.
int (pthread_attr_t *attr, int policy)
Set the scheduling policy attribute in a thread attributes object.
int (pthread_attr_t *attr, int contentionscope)
Set the contention scope attribute in a thread attributes object.
int (pthread_attr_t *attr, size_t stacksize)
Set the stack size attribute in a thread attributes object.
int (pthread_attr_t *attr, void *stackaddr)
Set the stack address attribute in a thread attributes object.
int (pthread_attr_t *attr, int detachstate)
Set the detach state in a thread attributes object.

int (pthread_mutexattr_t *attr)
Destroy a mutex attributes object.
int (const pthread_mutexattr_t *restrict attr, int *restrict ceiling)
Obtain priority ceiling attribute of mutex attribute object.
int (const pthread_mutexattr_t *restrict attr, int *restrict protocol)
Obtain protocol attribute of mutex attribute object.
int (const pthread_mutexattr_t *restrict attr, int *restrict type)
Obtain the mutex type attribute in the specified mutex attributes object.
int (pthread_mutexattr_t *attr)
Initialize a mutex attributes object with default values.
int (pthread_mutexattr_t *attr, int ceiling)
Set priority ceiling attribute of mutex attribute object.
int (pthread_mutexattr_t *attr, int protocol)
Set protocol attribute of mutex attribute object.
int (pthread_mutexattr_t *attr, int type)
Set the mutex type attribute that is used when a mutex is created.
int (pthread_mutex_t *mutex)
Destroy a mutex.
int (pthread_mutex_t *mutex, const pthread_mutexattr_t *attr);
Initialize a mutex with specified attributes.
int (pthread_mutex_t *mutex)
Lock a mutex and block until it becomes available.
int (pthread_mutex_t *mutex, const struct timespec *abstime);
Lock a mutex and block until it becomes available or until the timeout expires.
int (pthread_mutex_t *mutex)
Try to lock a mutex, but do not block if the mutex is locked by another thread, including the current thread.
int (pthread_mutex_t *mutex)
Unlock a mutex.

int (pthread_condattr_t *attr)
Destroy a condition variable attributes object.
int (pthread_condattr_t *attr)
Initialize a condition variable attributes object with default values.
int (pthread_cond_t *cond)
Unblock all threads currently blocked on the specified condition variable.
int (pthread_cond_t *cond)
Destroy a condition variable.
int (pthread_cond_t *cond, const pthread_condattr_t *attr)
Initialize a condition variable with specified attributes.
int (pthread_cond_t *cond)
Unblock at least one of the threads blocked on the specified condition variable.
int (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_t *, pthread_mutex_t *mutex)
Unlock the specified mutex, wait for a condition, and relock the mutex.

int (pthread_rwlock_t *lock)
Destroy a read/write lock object.
int (pthread_rwlock_t *lock, const pthread_rwlockattr_t *attr);
Initialize a read/write lock object.
int (pthread_rwlock_t *lock)
Lock a read/write lock for reading, blocking until the lock can be acquired.
int (pthread_rwlock_t *lock)
Attempt to lock a read/write lock for reading, without blocking if the lock is unavailable.
int (pthread_rwlock_t *lock)
Attempt to lock a read/write lock for writing, without blocking if the lock is unavailable.
int (pthread_rwlock_t *lock)
Unlock a read/write lock.
int (pthread_rwlock_t *lock)
Lock a read/write lock for writing, blocking until the lock can be acquired.
int (pthread_rwlockattr_t *attr)
Destroy a read/write lock attribute object.
int (const pthread_rwlockattr_t *attr, int *pshared);
Retrieve the process shared setting for the read/write lock attribute object.
int (pthread_rwlockattr_t *attr)
Initialize a read/write lock attribute object.
int (pthread_rwlockattr_t *attr, int pshared)
Set the process shared setting for the read/write lock attribute object.

int (pthread_key_t *key, void (*routine)(void *))
Create a thread-specific data key.
int (pthread_key_t key)
Delete a thread-specific data key.
void * (pthread_key_t key)
Get the thread-specific value for the specified key.
int (pthread_key_t key, const void *value_ptr)
Set the thread-specific value for the specified key.

int (void (*prepare)(void), void (*parent)(void), void (*child)(void));
Register fork handlers.
void (int execute)
Remove the routine at the top of the calling thread's cancellation cleanup stack and optionally invoke it.
void (void (*routine)(void *), void *routine_arg)
Push the specified cancellation cleanup handler onto the calling thread's cancellation stack.

The current FreeBSD POSIX thread implementation is built into the library “libthr” library. It contains thread-safe versions of library “libc” functions and the thread functions. Threaded applications are linked with this library.

libthr(3), pthread_affinity_np(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_destroy(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_mutexattr_getprioceiling(3), pthread_mutexattr_getprotocol(3), pthread_mutexattr_gettype(3), pthread_mutexattr_init(3), pthread_mutexattr_setprioceiling(3), pthread_mutexattr_setprotocol(3), pthread_mutexattr_settype(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_rwlockattr_getpshared(3), pthread_rwlockattr_init(3), pthread_rwlockattr_setpshared(3), pthread_self(3), pthread_setcancelstate(3), pthread_setcanceltype(3), pthread_setspecific(3), pthread_testcancel(3)

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 extensions 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”).

August 17, 2018 FreeBSD-12.0