nptl/pthread_spin_unlock.c


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/* pthread_spin_unlock -- unlock a spin lock.  Generic version.
   Copyright (C) 2003-2021 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;
}