nptl/pthread_key_delete.c

   1 /* Copyright (C) 2002-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include "pthreadP.h"
  21 #include <atomic.h>
  22
  23
  24 int
  25 pthread_key_delete (key)
  26      pthread_key_t key;
  27 {
  28   int result = EINVAL;
  29
  30   if (__glibc_likely (key < PTHREAD_KEYS_MAX))
  31     {
  32       unsigned int seq = __pthread_keys[key].seq;
  33
  34       if (__builtin_expect (! KEY_UNUSED (seq), 1)
  35           && ! atomic_compare_and_exchange_bool_acq (&__pthread_keys[key].seq,
  36                                                      seq + 1, seq))
  37         /* We deleted a valid key.  */
  38         result = 0;
  39     }
  40
  41   return result;
  42 }