1 /* Copyright (C) 2002, 2007 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 "pthreadP.h"
20 #include <lowlevellock.h>
21
22
23
24 static int once_lock = LLL_LOCK_INITIALIZER;
25
26
27 int
__pthread_once(pthread_once_t * once_control,void (* init_routine)(void))28 __pthread_once (
29 pthread_once_t *once_control,
30 void (*init_routine) (void))
31 {
32 /* XXX Depending on whether the LOCK_IN_ONCE_T is defined use a
33 global lock variable or one which is part of the pthread_once_t
34 object. */
35 if (*once_control == PTHREAD_ONCE_INIT)
36 {
37 lll_lock (once_lock, LLL_PRIVATE);
38
39 /* XXX This implementation is not complete. It doesn't take
40 cancellation and fork into account. */
41 if (*once_control == PTHREAD_ONCE_INIT)
42 {
43 init_routine ();
44
45 *once_control = !PTHREAD_ONCE_INIT;
46 }
47
48 lll_unlock (once_lock, LLL_PRIVATE);
49 }
50
51 return 0;
52 }
53 strong_alias (__pthread_once, pthread_once)
54