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PTHREAD_JOIN(3) Library Functions Manual PTHREAD_JOIN(3) NAME pthread_join, pthread_peekjoin_np, pthread_timedjoin_np pthread_tryjoin_np -- inspect thread termination state LIBRARY POSIX Threads Library (libpthread, -lpthread) SYNOPSIS #include <pthread.h> int pthread_join(pthread_t thread, void **value_ptr); #include <pthread_np.h> int pthread_peekjoin_np(pthread_t thread, void **value_ptr); int pthread_timedjoin_np(pthread_t thread, void **value_ptr, const struct timespec *abstime); int pthread_tryjoin_np(pthread_t thread, void **value_ptr); DESCRIPTION The pthread_join() function suspends execution of the calling thread until the target thread terminates unless the target thread has already terminated. On return from a successful pthread_join() call with a non-NULL value_ptr argument, the value passed to pthread_exit() by the terminat- ing thread is stored in the location referenced by value_ptr. When a pthread_join() returns successfully, the target thread has been termi- nated. The results of multiple simultaneous calls to pthread_join() specifying the same target thread are undefined. If the thread calling pthread_join() is cancelled, then the target thread is not detached. The pthread_timedjoin_np() function is equivalent to the pthread_join() function except it will return ETIMEDOUT if target thread does not exit before specified absolute time passes. The pthread_peekjoin_np() only peeks into the exit status of the speci- fied thread. If the thread has not exited, the EBUSY error is re- turned. Otherwise, zero is returned and the thread exit value is op- tionally stored into the location of *value_ptr. The target thread is left unjoined and can be used as an argument for the pthread_join() family of functions again. The pthread_tryjoin_np() function joins the thread if it is already terminated, same as pthread_join(). If the thread has not yet termi- nated, the function returns EBUSY. A thread that has exited but remains unjoined counts against [_POSIX_THREAD_THREADS_MAX]. RETURN VALUES If successful, the described functions return zero. Otherwise an error number is returned to indicate the error or special condition. ERRORS The pthread_join(), pthread_peekjoin_np(), and pthread_timedjoin_np() functions will fail if: [EINVAL] The implementation has detected that the value spec- ified by thread does not refer to a joinable thread. [ESRCH] No thread could be found corresponding to that spec- ified by the given thread ID, thread. [EDEADLK] A deadlock was detected or the value of thread spec- ifies the calling thread. [EOPNOTSUPP] The implementation detected that another caller is already waiting on thread. Additionally, the pthread_timedjoin_np() function will fail if: [ETIMEDOUT] The specified absolute time passed while pthread_timedjoin_np() waited for thread exit. The pthread_peekjoin_np() and pthread_tryjoin_np() functions will also fail if: [EBUSY] The specified thread has not yet exited. SEE ALSO wait(2), pthread(3), pthread_create(3), pthread_np(3) STANDARDS The pthread_join() function conforms to ISO/IEC 9945-1:1996 ("POSIX.1"). The pthread_timedjoin_np() function is a FreeBSD exten- sion which first appeared in FreeBSD 6.1. The pthread_peekjoin_np() function is a FreeBSD extension which first appearead in FreeBSD 13.0. The pthread_tryjoin_np() function is a FreeBSD extension which first appearead in FreeBSD 16.0. FreeBSD ports 15.1 October 12, 2021 PTHREAD_JOIN(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS
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