/* $NetBSD: once.h,v 1.7 2019/03/19 08:16:51 ryo Exp $ */ /*- * Copyright (c)2005 YAMAMOTO Takashi, * Copyright (c)2008 Antti Kantee, * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef _SYS_ONCE_H_ #define _SYS_ONCE_H_ typedef struct { int o_error; uint16_t o_refcnt; uint16_t o_status; #define ONCE_VIRGIN 0 #define ONCE_RUNNING 1 #define ONCE_DONE 2 } once_t; void once_init(void); int _init_once(once_t *, int (*)(void)); void _fini_once(once_t *, void (*)(void)); #define ONCE_DECL(o) \ once_t (o) = { \ .o_status = 0, \ .o_refcnt = 0, \ }; #define RUN_ONCE(o, fn) \ (__predict_true((o)->o_status == ONCE_DONE) ? \ ((o)->o_error) : _init_once((o), (fn))) #define INIT_ONCE(o, fn) _init_once((o), (fn)) #define FINI_ONCE(o, fn) _fini_once((o), (fn)) #endif /* _SYS_ONCE_H_ */ |