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 terminating thread is stored in the location referenced by
value_ptr. When a
pthread_join() returns successfully, the target thread has been terminated. 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.
A thread that has exited but remains unjoined counts against
_POSIX_THREAD_THREADS_MAX.