glibc/nptl/pthread_spin_unlock.c

32 lines
1.2 KiB
C

/* pthread_spin_unlock -- unlock a spin lock. Generic version.
Copyright (C) 2003-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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 "pthreadP.h"
#include <atomic.h>
int
pthread_spin_unlock (pthread_spinlock_t *lock)
{
/* The atomic_store_release synchronizes-with the atomic_exchange_acquire
or atomic_compare_exchange_weak_acquire in pthread_spin_lock /
pthread_spin_trylock. */
atomic_store_release (lock, 0);
return 0;
}