1 /* $NetBSD: once.h,v 1.9 2023/09/09 00:15:09 riastradh 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 int o_error; 35 uint16_t o_refcnt; 36 uint16_t o_status; 37 #define ONCE_VIRGIN 0 38 #define ONCE_RUNNING 1 39 #define ONCE_DONE 2 40 } once_t; 41 42 void once_init(void); 43 int _init_once(once_t *, int (*)(void)); 44 void _fini_once(once_t *, void (*)(void)); 45 46 #define ONCE_DECL(o) \ 47 once_t (o) = { \ 48 .o_status = 0, \ 49 .o_refcnt = 0, \ 50 }; 51 52 #define RUN_ONCE(o, fn) \ 53 (__predict_true((o)->o_status == ONCE_DONE) ? \ 54 ((o)->o_error) : _init_once((o), (fn))) 55 56 #define INIT_ONCE(o, fn) _init_once((o), (fn)) 57 #define FINI_ONCE(o, fn) _fini_once((o), (fn)) 58 59 #endif /* _SYS_ONCE_H_ */ 60