thr_join(3thread)                                  thr_join(3thread)


       NAME
             thr_join - join control paths with another thread

       SYNOPSIS
             cc [options] -Kthread file
             #include <thread.h>
             int thr_join(thread_t wait_for, thread_t *departed_thread, void **status);

          Parameters
             wait_for      the ID of the thread to wait for or 0

             departed_thread
                           pointer to the ID of the thread joined, set by
                           thr_join

             status        pointer to the joined thread's exit status

       DESCRIPTION
             thr_join waits for termination of the undetached sibling
             thread designated by wait_for and retrieves the exit status of
             the terminated thread [see thr_exit(3thread)].

             When the thread being waited for (wait_for) terminates, and
             thr_join returns, we say that the terminated thread has joined
             control paths with the thread that called thr_join.  When a
             thread calls thr_join, we say that it is waiting for a thread.

          wait_for Parameter
             If wait_for is set to the thread ID of an undetached sibling
             thread, thr_join waits for that thread to terminate.  If
             wait_for is equal to (thread_t)0, thr_join waits for
             termination of any undetached sibling thread, and returns when
             the first one completes thr_exit.

             Threads created with the THR_DETACHED flag cannot be joined.

          departed_thread Parameter
             If the value of the pointer departed_thread is not NULL,
             thr_join sets the location pointed to by departed_thread to
             the identifier of the terminated sibling thread.  This tells
             the calling thread which thread it joined.

          status Parameter
             If status is not NULL, the location pointed to by status is
             set to the exit status from the terminated sibling thread.



                           Copyright 1994 Novell, Inc.               Page 1

      thr_join(3thread)                                  thr_join(3thread)


            Only one thread can successfully return from a thr_join for a
            given departed_thread.  If more than one thread is waiting for
            a specific thread to terminate, one is successful and the
            others fail with error indication ESRCH.  This allows exactly
            one thread to join with and obtain status from a given thread.

            If wait_for has already been thr_joined, or otherwise is not
            known by the implementation, an ESRCH is returned.

            The wait in thr_join is not broken by a signal.  If a thread
            waiting in thr_join receives a signal that is not masked, if
            will execute the signal handler, and then return to waiting in
            thr_join.  Note that this behavior differs from that of
            cond_wait [see condition(3synch)].

         Return Values
            thr_join returns zero for success and an error number on
            failure, as described below.

         Errors
            If any of the following conditions occurs, thr_join returns
            the corresponding value:

            ESRCH    there is no joinable (undetached) thread in the
                     current process with thread ID wait_for.

            EDEADLK  wait_for is the calling thread's thread ID.

            EINVAL   wait_for is (thread_t) 0, and there are no undetached
                     sibling threads to wait for.

      REFERENCES
            condition(3synch), _lwp_wait(2), thr_create(3thread),
            thr_exit(3thread), thread(3thread), wait(2)














                          Copyright 1994 Novell, Inc.               Page 2