redhat man page for pthread_join

PTHREAD_JOIN(3) 					     Library Functions Manual						   PTHREAD_JOIN(3)

NAME
       pthread_join - wait for termination of another thread

SYNOPSIS
       #include <pthread.h>

       int pthread_join(pthread_t th, void **thread_return);

DESCRIPTION
       pthread_join  suspends  the execution of the calling thread until the thread identified by th terminates, either by calling pthread_exit(3)
       or by being cancelled.

       If thread_return is not NULL, the return value of th is stored in the location pointed to by thread_return.  The  return  value	of  th	is
       either the argument it gave to pthread_exit(3), or PTHREAD_CANCELED if th was cancelled.

       The  joined  thread th must be in the joinable state: it must not have been detached using pthread_detach(3) or the PTHREAD_CREATE_DETACHED
       attribute to pthread_create(3).

       When a joinable thread terminates, its memory resources (thread descriptor and stack) are not deallocated  until  another  thread  performs
       pthread_join on it. Therefore, pthread_join must be called once for each joinable thread created to avoid memory leaks.

       At  most  one thread can wait for the termination of a given thread. Calling pthread_join on a thread th on which another thread is already
       waiting for termination returns an error.

CANCELLATION
       pthread_join is a cancellation point. If a thread is canceled while suspended in pthread_join, the thread execution resumes immediately and
       the  cancellation  is  executed	without  waiting for the th thread to terminate. If cancellation occurs during pthread_join, the th thread
       remains not joined.

RETURN VALUE
       On success, the return value of th is stored in the location pointed to by thread_return, and 0 is returned. On	error,	a  non-zero  error
       code is returned.

ERRORS
       ESRCH  No thread could be found corresponding to that specified by th.

       EINVAL The th thread has been detached.

       EINVAL Another thread is already waiting on termination of th.

       EDEADLK
	      The th argument refers to the calling thread.

AUTHOR
       Xavier Leroy <Xavier.Leroy@inria.fr>

SEE ALSO
       pthread_exit(3), pthread_detach(3), pthread_create(3), pthread_attr_setdetachstate(3), pthread_cleanup_push(3), pthread_key_create(3).

								   LinuxThreads 						   PTHREAD_JOIN(3)