1/*	$NetBSD: once.c,v 1.2.6.1 2012/06/05 21:15:31 bouyer Exp $	*/
2
3/*
4 * Copyright (C) 2004, 2007  Internet Systems Consortium, Inc. ("ISC")
5 * Copyright (C) 1999-2001  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.c,v 1.12 2007/06/18 23:47:49 tbox Exp  */
21
22/* Principal Authors: DCL */
23
24#include <config.h>
25
26#include <windows.h>
27
28#include <isc/once.h>
29#include <isc/assertions.h>
30#include <isc/util.h>
31
32isc_result_t
33isc_once_do(isc_once_t *controller, void(*function)(void)) {
34	REQUIRE(controller != NULL && function != NULL);
35
36	if (controller->status == ISC_ONCE_INIT_NEEDED) {
37
38		if (InterlockedDecrement(&controller->counter) == 0) {
39			if (controller->status == ISC_ONCE_INIT_NEEDED) {
40				function();
41				controller->status = ISC_ONCE_INIT_DONE;
42			}
43		} else {
44			while (controller->status == ISC_ONCE_INIT_NEEDED) {
45				/*
46				 * Sleep(0) indicates that this thread
47				 * should be suspended to allow other
48				 * waiting threads to execute.
49				 */
50				Sleep(0);
51			}
52		}
53	}
54
55	return (ISC_R_SUCCESS);
56}
57