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/* pthread_once. Generic version.
Copyright (C) 2002-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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, see
<https://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <atomic.h>
#include <pt-internal.h>
#include <shlib-compat.h>
static void
clear_once_control (void *arg)
{
pthread_once_t *once_control = arg;
__pthread_spin_unlock (&once_control->__lock);
}
int
__pthread_once (pthread_once_t *once_control, void (*init_routine) (void))
{
ASSERT_TYPE_SIZE (pthread_once_t, __SIZEOF_PTHREAD_ONCE_T);
atomic_full_barrier ();
if (once_control->__run == 0)
{
__pthread_spin_wait (&once_control->__lock);
if (once_control->__run == 0)
{
pthread_cleanup_push (clear_once_control, once_control);
init_routine ();
pthread_cleanup_pop (0);
atomic_full_barrier ();
once_control->__run = 1;
}
__pthread_spin_unlock (&once_control->__lock);
}
return 0;
}
libc_hidden_def (__pthread_once)
versioned_symbol (libc, __pthread_once, pthread_once, GLIBC_2_41);
#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_12, GLIBC_2_41)
compat_symbol (libpthread, __pthread_once, pthread_once, GLIBC_2_12);
#endif
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