| 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 | |