1/*	$NetBSD: once.h,v 1.2.6.1 2012/06/05 21:15:26 bouyer Exp $	*/
2
3/*
4 * Copyright (C) 2004, 2007  Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (C) 2000, 2001  Internet Software Consortium.
6 *
7 * Permission to use, copy, modify, and/or distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
12 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
13 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
14 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
15 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
16 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
17 * PERFORMANCE OF THIS SOFTWARE.
18 */
19
20/* Id: once.h,v 1.6 2007/06/19 23:47:18 tbox Exp  */
21
22#ifndef ISC_ONCE_H
23#define ISC_ONCE_H 1
24
25#include <isc/result.h>
26
27typedef isc_boolean_t isc_once_t;
28
29#define ISC_ONCE_INIT ISC_FALSE
30
31#define isc_once_do(op, f) \
32	(!*(op) ? (f(), *(op) = ISC_TRUE, ISC_R_SUCCESS) : ISC_R_SUCCESS)
33
34#endif /* ISC_ONCE_H */
35