glibc/sysdeps/htl/pt-once.c

45 lines
1.3 KiB
C

/* pthread_once. Generic version.
Copyright (C) 2002-2018 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
<http://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <atomic.h>
#include <pt-internal.h>
int
__pthread_once (pthread_once_t *once_control, void (*init_routine) (void))
{
atomic_full_barrier ();
if (once_control->__run == 0)
{
__pthread_spin_lock (&once_control->__lock);
if (once_control->__run == 0)
{
init_routine ();
atomic_full_barrier ();
once_control->__run = 1;
}
__pthread_spin_unlock (&once_control->__lock);
}
return 0;
}
strong_alias (__pthread_once, pthread_once);