1 | /* pthread_once. Generic version. |
---|---|
2 | Copyright (C) 2002-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
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 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <pthread.h> |
20 | #include <atomic.h> |
21 | |
22 | #include <pt-internal.h> |
23 | |
24 | static void |
25 | clear_once_control (void *arg) |
26 | { |
27 | pthread_once_t *once_control = arg; |
28 | __pthread_spin_unlock (&once_control->__lock); |
29 | } |
30 | |
31 | int |
32 | __pthread_once (pthread_once_t *once_control, void (*init_routine) (void)) |
33 | { |
34 | ASSERT_TYPE_SIZE (pthread_once_t, __SIZEOF_PTHREAD_ONCE_T); |
35 | |
36 | atomic_full_barrier (); |
37 | if (once_control->__run == 0) |
38 | { |
39 | __pthread_spin_wait (&once_control->__lock); |
40 | |
41 | if (once_control->__run == 0) |
42 | { |
43 | pthread_cleanup_push (clear_once_control, once_control); |
44 | init_routine (); |
45 | pthread_cleanup_pop (0); |
46 | |
47 | atomic_full_barrier (); |
48 | once_control->__run = 1; |
49 | } |
50 | |
51 | __pthread_spin_unlock (&once_control->__lock); |
52 | } |
53 | |
54 | return 0; |
55 | } |
56 | weak_alias (__pthread_once, pthread_once); |
57 |