pthread_join - wait for termination of another thread
int pthread_join(pthread_t th, void **thread_return);
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
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.
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 ter-
minate. If cancellation occurs during pthread_join, the th thread
remains not joined.
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
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.
The th argument refers to the calling thread.
Xavier Leroy <Xavier.Leroy@inria.fr>
pthread_exit(3), pthread_detach(3), pthread_create(3),