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-rw-r--r--libpthread/nptl/pthread_tryjoin.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/libpthread/nptl/pthread_tryjoin.c b/libpthread/nptl/pthread_tryjoin.c
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+/* Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <stdlib.h>
+
+#include <atomic.h>
+#include "pthreadP.h"
+
+
+int
+pthread_tryjoin_np (
+ pthread_t threadid,
+ void **thread_return)
+{
+ struct pthread *self;
+ struct pthread *pd = (struct pthread *) threadid;
+
+ /* Make sure the descriptor is valid. */
+ if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
+ /* Not a valid thread handle. */
+ return ESRCH;
+
+ /* Is the thread joinable?. */
+ if (IS_DETACHED (pd))
+ /* We cannot wait for the thread. */
+ return EINVAL;
+
+ self = THREAD_SELF;
+ if (pd == self || self->joinid == pd)
+ /* This is a deadlock situation. The threads are waiting for each
+ other to finish. Note that this is a "may" error. To be 100%
+ sure we catch this error we would have to lock the data
+ structures but it is not necessary. In the unlikely case that
+ two threads are really caught in this situation they will
+ deadlock. It is the programmer's problem to figure this
+ out. */
+ return EDEADLK;
+
+ /* Return right away if the thread hasn't terminated yet. */
+ if (pd->tid != 0)
+ return EBUSY;
+
+ /* Wait for the thread to finish. If it is already locked something
+ is wrong. There can only be one waiter. */
+ if (atomic_compare_and_exchange_bool_acq (&pd->joinid, self, NULL))
+ /* There is already somebody waiting for the thread. */
+ return EINVAL;
+
+ /* Store the return value if the caller is interested. */
+ if (thread_return != NULL)
+ *thread_return = pd->result;
+
+
+ /* Free the TCB. */
+ __free_tcb (pd);
+
+ return 0;
+}