1 | /* $NetBSD: once.h,v 1.5 2008/10/09 10:48:21 pooka Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c)2005 YAMAMOTO Takashi, |
5 | * Copyright (c)2008 Antti Kantee, |
6 | * All rights reserved. |
7 | * |
8 | * Redistribution and use in source and binary forms, with or without |
9 | * modification, are permitted provided that the following conditions |
10 | * are met: |
11 | * 1. Redistributions of source code must retain the above copyright |
12 | * notice, this list of conditions and the following disclaimer. |
13 | * 2. Redistributions in binary form must reproduce the above copyright |
14 | * notice, this list of conditions and the following disclaimer in the |
15 | * documentation and/or other materials provided with the distribution. |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
27 | * SUCH DAMAGE. |
28 | */ |
29 | |
30 | #ifndef _SYS_ONCE_H_ |
31 | #define _SYS_ONCE_H_ |
32 | |
33 | typedef struct { |
34 | unsigned o_status; |
35 | int o_error; |
36 | #define ONCE_VIRGIN 0 |
37 | #define ONCE_RUNNING 1 |
38 | #define ONCE_DONE 2 |
39 | } once_t; |
40 | |
41 | void once_init(void); |
42 | int _run_once(once_t *, int (*)(void)); |
43 | |
44 | #define ONCE_DECL(o) \ |
45 | once_t (o) = { \ |
46 | .o_status = 0, \ |
47 | }; |
48 | |
49 | #define RUN_ONCE(o, fn) \ |
50 | (__predict_true((o)->o_status == ONCE_DONE) ? \ |
51 | ((o)->o_error) : _run_once((o), (fn))) |
52 | |
53 | #endif /* _SYS_ONCE_H_ */ |
54 | |