/* Copyright (C) 2002-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   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 <errno.h>

#include "pthreadP.h"

#include <atomic.h>

int

__pthread_key_create (pthread_key_t *key, void (*destr) (void *))

{

  /* Find a slot in __pthread_keys which is unused.  */

  for (size_t cnt = 0; cnt < PTHREAD_KEYS_MAX; ++cnt)

    {

      uintptr_t seq = __pthread_keys[cnt].seq;

      if (KEY_UNUSED (seq) && KEY_USABLE (seq)

	  /* We found an unused slot.  Try to allocate it.  */

	  && ! atomic_compare_and_exchange_bool_acq (&__pthread_keys[cnt].seq,

						     seq + 1, seq))

	{

	  /* Remember the destructor.  */

	  __pthread_keys[cnt].destr = destr;

	  /* Return the key to the caller.  */

	  *key = cnt;

	  /* The call succeeded.  */

	  return 0;

	}

    }

  return EAGAIN;

}

weak_alias (__pthread_key_create, pthread_key_create)

hidden_def (__pthread_key_create)