lib/libpthread/pthreads/pthread_detach.c

/* ==== pthread_detach.c =======================================================
 * Copyright (c) 1994 by Chris Provenzano, proven@mit.edu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by Chris Provenzano.
 * 4. The name of Chris Provenzano may not be used to endorse or promote
 *        products derived from this software without specific prior written
 *        permission.
 *
 * THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Description : pthread_join function.
 *
 *  1.00 94/01/15 proven
 *      -Started coding this file.
 */

#include <pthread.h>

/* ==========================================================================
 * pthread_detach()
 */
int pthread_detach(pthread_t pthread)
{
        semaphore *plock;
        int ret;

        plock = &(pthread->lock);
        while (SEMAPHORE_TEST_AND_SET(plock)) {
                pthread_yield();
        }

        /* Check that thread isn't detached already */
        if (!(pthread->flags & PF_DETACHED)) {

                pthread->flags |= PF_DETACHED;

                /* Wakeup first threads waiting on a join */
                {
                        struct pthread * next_thread;
                        semaphore * next_lock;

                        if (next_thread = pthread_queue_get(&(pthread->join_queue))) {
                                next_lock = &(next_thread->lock);
                                while (SEMAPHORE_TEST_AND_SET(next_lock)) {
                                        pthread_yield();
                                }
                                pthread_queue_deq(&(pthread->join_queue));
                                next_thread->state = PS_RUNNING;
                                /*
                                 * Thread will wake up in pthread_join(), see the thread
                                 * it was joined to already detached and unlock itself
                                 * and pthread
                                 */
                        } else {
                                SEMAPHORE_RESET(plock);
                        }
                }
                ret = OK;

        } else {
                SEMAPHORE_RESET(plock);
                ret = ESRCH;
        }
        return(ret);
}