thrd_join3
C11 threads interface
Part of call_once(3).
Usage
void
int
void
int
int
int
int
void
int
int
int
int
int
int
thrd_t
int
int
_Noreturn void
int
int
void
int
void
void *
int
Library
library “libstdthreads”
Overview
As of ISO/IEC 9899:2011 (“ISO C11”), the C standard includes an API for writing multithreaded applications. Since POSIX.1 already includes a threading API that is used by virtually any multithreaded application, the interface provided by the C standard can be considered superfluous.
In this implementation, the threading interface is therefore implemented as a light-weight layer on top of existing interfaces. The functions to which these routines are mapped, are listed in the following table. Please refer to the documentation of the POSIX equivalent functions for more information.
| Function | POSIX equivalent |
| call_once() | pthread_once(3) |
| cnd_broadcast() | pthread_cond_broadcast(3) |
| cnd_destroy() | pthread_cond_destroy(3) |
| cnd_init() | pthread_cond_init(3) |
| cnd_signal() | pthread_cond_signal(3) |
| cnd_timedwait() | pthread_cond_timedwait(3) |
| cnd_wait() | pthread_cond_wait(3) |
| mtx_destroy() | pthread_mutex_destroy(3) |
| mtx_init() | pthread_mutex_init(3) |
| mtx_lock() | pthread_mutex_lock(3) |
| mtx_timedlock() | pthread_mutex_timedlock(3) |
| mtx_trylock() | pthread_mutex_trylock(3) |
| mtx_unlock() | pthread_mutex_unlock(3) |
| thrd_create() | pthread_create(3) |
| thrd_current() | pthread_self(3) |
| thrd_detach() | pthread_detach(3) |
| thrd_equal() | pthread_equal(3) |
| thrd_exit() | pthread_exit(3) |
| thrd_join() | pthread_join(3) |
| thrd_sleep() | nanosleep(2) |
| thrd_yield() | pthread_yield(3) |
| tss_create() | pthread_key_create(3) |
| tss_delete() | pthread_key_delete(3) |
| tss_get() | pthread_getspecific(3) |
| tss_set() | pthread_setspecific(3) |
Differences with POSIX equivalents
The thrd_exit() function returns an integer value to the thread calling thrd_join(), whereas the pthread_exit() function uses a pointer.
The mutex created by mtx_init() can be of type mtx_plain or mtx_timed to distinguish between a mutex that supports mtx_timedlock(). This type can be or'd with mtx_recursive to create a mutex that allows recursive acquisition. These properties are normally set using pthread_mutex_init(Ns, 's) attr parameter.
Return values
If successful, the cnd_broadcast(), cnd_init(), cnd_signal(), cnd_timedwait(), cnd_wait(), mtx_init(), mtx_lock(), mtx_timedlock(), mtx_trylock(), mtx_unlock(), thrd_create(), thrd_detach(), thrd_equal(), thrd_join(), thrd_sleep(), tss_create() and tss_set() functions return thrd_success. Otherwise an error code will be returned to indicate the error.
The thrd_current() function returns the thread ID of the calling thread.
The tss_get() function returns the thread-specific data value associated with the given key. If no thread-specific data value is associated with key, then the value NULL is returned.
Errors
The cnd_init() and thrd_create() functions will fail if:
- thrd_nomem
-
The system has insufficient memory.
The cnd_timedwait() and mtx_timedlock() functions will fail if:
- thrd_timedout
-
The system time has reached or exceeded the time specified in ts before the operation could be completed.
The mtx_trylock() function will fail if:
- thrd_busy
-
The mutex is already locked.
In all other cases, these functions may fail by returning general error code thrd_error.
History
- FreeBSD 16.0-CURRENT (2026-10-27) to FreeBSD 13.3-RELEASE: the text shown here
- FreeBSD 13.2-RELEASE to FreeBSD 13.0-RELEASE
- FreeBSD 12.4-RELEASE
- FreeBSD 12.3-RELEASE
- FreeBSD 12.2-RELEASE
- FreeBSD 12.1-RELEASE
- FreeBSD 12.0-RELEASE
- FreeBSD 11.4-RELEASE
- FreeBSD 11.3-RELEASE
- FreeBSD 11.2-RELEASE
- FreeBSD 11.1-RELEASE
- FreeBSD 11.0-RELEASE
- FreeBSD 10.4-RELEASE
- FreeBSD 10.3-RELEASE
- FreeBSD 10.2-RELEASE
- FreeBSD 10.1-RELEASE
- FreeBSD 10.0-RELEASE