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			75 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			75 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <http://www.gnu.org/licenses/>.  */
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#include <errno.h>
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#include <stdlib.h>
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#include <atomic.h>
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#include "pthreadP.h"
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int
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pthread_tryjoin_np (threadid, thread_return)
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     pthread_t threadid;
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     void **thread_return;
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{
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  struct pthread *self;
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  struct pthread *pd = (struct pthread *) threadid;
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  /* Make sure the descriptor is valid.  */
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  if (DEBUGGING_P && __find_in_stack_list (pd) == NULL)
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    /* Not a valid thread handle.  */
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    return ESRCH;
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  /* Is the thread joinable?.  */
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  if (IS_DETACHED (pd))
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    /* We cannot wait for the thread.  */
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    return EINVAL;
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  self = THREAD_SELF;
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  if (pd == self || self->joinid == pd)
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    /* This is a deadlock situation.  The threads are waiting for each
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       other to finish.  Note that this is a "may" error.  To be 100%
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       sure we catch this error we would have to lock the data
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       structures but it is not necessary.  In the unlikely case that
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       two threads are really caught in this situation they will
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       deadlock.  It is the programmer's problem to figure this
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       out.  */
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    return EDEADLK;
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  /* Return right away if the thread hasn't terminated yet.  */
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  if (pd->tid != 0)
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    return EBUSY;
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  /* Wait for the thread to finish.  If it is already locked something
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     is wrong.  There can only be one waiter.  */
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  if (atomic_compare_and_exchange_bool_acq (&pd->joinid, self, NULL))
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    /* There is already somebody waiting for the thread.  */
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    return EINVAL;
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  /* Store the return value if the caller is interested.  */
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  if (thread_return != NULL)
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    *thread_return = pd->result;
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  /* Free the TCB.  */
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  __free_tcb (pd);
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  return 0;
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}
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