nptl/pthread_key_delete.c

   1 /* Copyright (C) 2002, 2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include "pthreadP.h"
  22 #include <atomic.h>
  23
  24
  25 int
  26 pthread_key_delete (key)
  27      pthread_key_t key;
  28 {
  29   int result = EINVAL;
  30
  31   if (__builtin_expect (key < PTHREAD_KEYS_MAX, 1))
  32     {
  33       unsigned int seq = __pthread_keys[key].seq;
  34
  35       if (__builtin_expect (! KEY_UNUSED (seq), 1)
  36           && ! atomic_compare_and_exchange_bool_acq (&__pthread_keys[key].seq,
  37                                                      seq + 1, seq))
  38         /* We deleted a valid key.  */
  39         result = 0;
  40     }
  41
  42   return result;
  43 }