DragonFly On-Line Manual Pages
PTHREAD(3) DragonFly 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
requirements 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
* Spin Lock Routines
* Barrier Routines
* Per-Thread Context Routines
* Cleanup Routines
Thread Routines
int pthread_create(pthread_t * restrict thread,
const pthread_attr_t * restrict attr,
void *(*start_routine)(void *), void * restrict 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_getconcurrency(void)
Get the current thread's level of concurrency.
int pthread_getcpuclockid(pthread_t thread, clockid_t *clock_id)
Access a specific thread's CPU-time clock.
int pthread_getschedparam(pthread_t thread, int * restrict policy, struct
sched_param * restrict param)
Get the scheduling parameters of a specific thread.
int pthread_join(pthread_t thread, void **value_ptr)
Causes the calling thread to wait for the termination of the
specified 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.
int pthread_setconcurrency(int new_level)
Set the current thread's level of concurrency.
int pthread_setschedparam(pthread_t thread, int policy, struct
sched_param *param)
Set the scheduling parameters for a specific thread.
void pthread_sigmask(int how, const sigset_t * restrict set, sigset_t *
restrict oset)
Examine and/or change the calling thread's signal mask.
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_getguardsize(const pthread_attr_t * restrict attr,
size_t * restrict guardsize)
Get the guard size attribute from a thread attributes object.
int pthread_attr_getinheritsched(const pthread_attr_t * restrict attr,
int * restrict inheritsched)
Get the inherit scheduling attribute from a thread attributes
object.
int pthread_attr_getschedparam(const pthread_attr_t * restrict attr,
struct sched_param * restrict param)
Get the scheduling parameter attribute from a thread attributes
object.
int pthread_attr_getschedpolicy(const pthread_attr_t * restrict attr, int
* restrict policy)
Get the scheduling policy attribute from a thread attributes
object.
int pthread_attr_getscope(const pthread_attr_t * restrict attr, int *
restrict contentionscope)
Get the contention scope attribute from a thread attributes
object.
int pthread_attr_getstack(const pthread_attr_t * restrict attr, void **
restrict stackaddr, size_t * restrict stacksize)
Get the stack attributes from a thread attributes object.
int pthread_attr_getstacksize(const pthread_attr_t * restrict attr,
size_t * restrict stacksize)
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
*detachstate)
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_setguardsize(pthread_attr_t *attr, size_t guardsize)
Set the guard size attribute in a thread attributes object.
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 * restrict attr,
const struct sched_param * restrict param)
Set the scheduling parameter attribute in a thread attributes
object.
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_setstack(pthread_attr_t *attr, void *stackaddr, size_t
stacksize)
Set the stack attributes 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_getpshared(const pthread_mutexattr_t * restrict
attr, int * restrict pshared)
Get the process shared setting from a mutex attributes 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
ceiling)
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_setpshared(pthread_mutexattr_t *attr, int pshared)
Set the process shared setting in a mutex attributes 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_getprioceiling(const pthread_mutex_t * restrict mutex,
int * restrict ceiling)
Get the priority ceiling of a mutex.
int pthread_mutex_init(pthread_mutex_t * restrict mutex,
const pthread_mutexattr_t * restrict 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_setprioceiling(pthread_mutex_t * restrict mutex, int
ceiling, int * restrict old_ceiling)
Set the priority ceiling of a mutex.
int pthread_mutex_timedlock(pthread_mutex_t * restrict mutex,
const struct timespec * restrict 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
another 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_getclock(const pthread_condattr_t * restrict attr,
clockid_t * restrict clock_id)
Get the clock selection attribute from a condition variable
attributes object.
int pthread_condattr_init(pthread_condattr_t *attr)
Initialize a condition variable attributes object with default
values.
int pthread_condattr_getpshared(const pthread_condattr_t * restrict attr,
int * restrict pshared)
Get the process shared setting from a condition variable
attributes object.
int pthread_condattr_setclock(pthread_condattr_t *attr, clockid_t
clock_id)
Set the clock selection attribute in a condition variable
attributes object.
int pthread_condattr_setpshared(pthread_condattr_t *attr, int pshared)
Set the process shared setting in a condition variable attributes
object.
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 * restrict cond, const
pthread_condattr_t * restrict 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
condition variable.
int pthread_cond_timedwait(pthread_cond_t * restrict cond,
pthread_mutex_t * restrict mutex,
const struct timespec * restrict abstime)
Wait no longer than the specified time for a condition and lock
the specified mutex.
int pthread_cond_wait(pthread_cond_t * restrict cond, pthread_mutex_t *
restrict mutex)
Wait for a condition and lock the specified 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 * restrict lock,
const pthread_rwlockattr_t * restrict 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_timedrdlock(pthread_rwlock_t * restrict lock, const
struct timespec * restrict abstime)
Lock a read/write lock for reading with a timeout.
int pthread_rwlock_timedwrlock(pthread_rwlock_t * restrict lock, const
struct timespec * restrict abstime)
Lock a read/write lock for writing with a timeout.
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 *
restrict attr, int * restrict pshared)
Retrieve the process shared setting for the read/write lock
attribute 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.
Spin Lock Routines
int pthread_spin_destroy(pthread_spinlock_t *lock)
Destroy a spin lock object.
int pthread_spin_init(pthread_spinlock_t *lock, int pshared)
Initialize a spin lock object.
int pthread_spin_lock(pthread_spinlock_t *lock)
Lock a spin lock object.
int pthread_spin_trylock(pthread_spinlock_t *lock)
Lock a spin lock object if it is not held.
int pthread_spin_unlock(pthread_spinlock_t *lock)
Unlock a spin lock object.
Barrier Routines
int pthread_barrier_destroy(pthread_barrier_t *barrier)
Delete a barrier and its resources.
int pthread_barrier_init(pthread_barrier_t * restrict barrier, const
pthread_barrierattr_t * restrict attr, unsigned count)
Initialize a barrier with the specified attribute object.
int pthread_barrier_wait(pthread_barrier_t *barrier)
Block the calling threads until the barrier count is reached.
int pthread_barrierattr_destroy(pthread_barrierattr_t *attr)
Destroy a barrier attribute object.
int pthread_barrierattr_getpshared(const pthread_barrierattr_t * restrict
attr, int * restrict pshared)
Get the process-shared attribute from a barrier attribute object.
int pthread_barrierattr_init(pthread_barrierattr_t *attr)
Initialize a barrier attribute object.
int pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int
pshared)
Set the process-shared attribute in a barrier 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 DragonFly POSIX thread implementation lives in the library
libc.
The libpthread.so.0 and libthread_xu.so.2 libraries are compatibility
shims to make existing dynamically linked binaries with DT_NEEDED entries
for either library name continue to load. The libpthread.so and
libpthread.a symlinks remain available for build systems that still link
with -lpthread.
SEE ALSO
pthread_atfork(3), pthread_attr_destroy(3),
pthread_attr_getdetachstate(3), pthread_attr_getguardsize(3),
pthread_attr_getinheritsched(3), pthread_attr_getschedparam(3),
pthread_attr_getschedpolicy(3), pthread_attr_getscope(3),
pthread_attr_getstack(3), pthread_attr_getstackaddr(3),
pthread_attr_getstacksize(3), pthread_attr_init(3),
pthread_attr_setdetachstate(3), pthread_attr_setguardsize(3),
pthread_attr_setinheritsched(3), pthread_attr_setschedparam(3),
pthread_attr_setschedpolicy(3), pthread_attr_setscope(3),
pthread_attr_setstack(3), pthread_attr_setstackaddr(3),
pthread_attr_setstacksize(3), pthread_barrierattr_destroy(3),
pthread_barrierattr_getpshared(3), pthread_barrierattr_init(3),
pthread_barrierattr_setpshared(3), pthread_barrier_destroy(3),
pthread_barrier_init(3), pthread_barrier_wait(3), pthread_cancel(3),
pthread_cleanup_pop(3), pthread_cleanup_push(3),
pthread_condattr_destroy(3), pthread_condattr_getclock(3),
pthread_condattr_getpshared(3), pthread_condattr_init(3),
pthread_condattr_setclock(3), pthread_condattr_setpshared(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_create(3), pthread_detach(3), pthread_equal(3), pthread_exit(3),
pthread_getconcurrency(3), pthread_getcpuclockid(3),
pthread_getschedparam(3), pthread_getspecific(3), pthread_join(3),
pthread_key_create(3), pthread_key_delete(3), pthread_kill(3),
pthread_mutexattr_destroy(3), pthread_mutexattr_getprioceiling(3),
pthread_mutexattr_getprotocol(3), pthread_mutexattr_getpshared(3),
pthread_mutexattr_gettype(3), pthread_mutexattr_init(3),
pthread_mutexattr_setprioceiling(3), pthread_mutexattr_setprotocol(3),
pthread_mutexattr_setpshared(3), pthread_mutexattr_settype(3),
pthread_mutex_destroy(3), pthread_mutex_getprioceiling(3),
pthread_mutex_init(3), pthread_mutex_lock(3),
pthread_mutex_setprioceiling(3), pthread_mutex_timedlock(3),
pthread_mutex_trylock(3), pthread_mutex_unlock(3), pthread_once(3),
pthread_rwlockattr_destroy(3), pthread_rwlockattr_getpshared(3),
pthread_rwlockattr_init(3), pthread_rwlockattr_setpshared(3),
pthread_rwlock_destroy(3), pthread_rwlock_init(3),
pthread_rwlock_rdlock(3), pthread_rwlock_timedrdlock(3),
pthread_rwlock_timedwrlock(3), pthread_rwlock_tryrdlock(3),
pthread_rwlock_trywrlock(3), pthread_rwlock_unlock(3),
pthread_rwlock_wrlock(3), pthread_self(3), pthread_setcancelstate(3),
pthread_setcanceltype(3), pthread_setconcurrency(3),
pthread_setschedparam(3), pthread_setspecific(3), pthread_sigmask(3),
pthread_spin_destroy(3), pthread_spin_init(3), pthread_spin_lock(3),
pthread_spin_trylock(3), pthread_spin_unlock(3), pthread_testcancel(3),
pthread_yield(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
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").
DragonFly 6.5-DEVELOPMENT September 17, 2026 DragonFly 6.5-DEVELOPMENT