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57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
/* pthread_once. Generic version.
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Copyright (C) 2002-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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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<https://www.gnu.org/licenses/>. */
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#include <pthread.h>
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#include <atomic.h>
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#include <pt-internal.h>
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static void
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clear_once_control (void *arg)
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{
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pthread_once_t *once_control = arg;
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__pthread_spin_unlock (&once_control->__lock);
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}
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int
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__pthread_once (pthread_once_t *once_control, void (*init_routine) (void))
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{
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ASSERT_TYPE_SIZE (pthread_once_t, __SIZEOF_PTHREAD_ONCE_T);
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atomic_full_barrier ();
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if (once_control->__run == 0)
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{
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__pthread_spin_wait (&once_control->__lock);
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if (once_control->__run == 0)
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{
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pthread_cleanup_push (clear_once_control, once_control);
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init_routine ();
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pthread_cleanup_pop (0);
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atomic_full_barrier ();
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once_control->__run = 1;
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}
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__pthread_spin_unlock (&once_control->__lock);
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}
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return 0;
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}
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weak_alias (__pthread_once, pthread_once);
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