/* Try to acquire a rwlock for writing.  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 <assert.h>

#include <pt-internal.h>

/* Try to acquire RWLOCK for writing.  */

int

pthread_rwlock_trywrlock (struct __pthread_rwlock *rwlock)

{

  __pthread_spin_lock (&rwlock->__lock);

  if (__pthread_spin_trylock (&rwlock->__held) == 0)

    /* Successfully acquired the lock.  */

    {

      assert (rwlock->__readerqueue == 0);

      assert (rwlock->__writerqueue == 0);

      assert (rwlock->__readers == 0);

      __pthread_spin_unlock (&rwlock->__lock);

      return 0;

    }

  /* The lock is busy.  */

  __pthread_spin_unlock (&rwlock->__lock);

  return EBUSY;

}