1258945Sroberto/*
2258945Sroberto * Copyright (C) 2004, 2007  Internet Systems Consortium, Inc. ("ISC")
3258945Sroberto * Copyright (C) 1999-2001  Internet Software Consortium.
4258945Sroberto *
5258945Sroberto * Permission to use, copy, modify, and/or distribute this software for any
6258945Sroberto * purpose with or without fee is hereby granted, provided that the above
7258945Sroberto * copyright notice and this permission notice appear in all copies.
8258945Sroberto *
9258945Sroberto * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10258945Sroberto * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11258945Sroberto * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12258945Sroberto * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13258945Sroberto * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14258945Sroberto * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15258945Sroberto * PERFORMANCE OF THIS SOFTWARE.
16258945Sroberto */
17258945Sroberto
18258945Sroberto/* $Id: once.c,v 1.12 2007/06/18 23:47:49 tbox Exp $ */
19258945Sroberto
20258945Sroberto/* Principal Authors: DCL */
21258945Sroberto
22258945Sroberto#include <config.h>
23258945Sroberto
24258945Sroberto#include <windows.h>
25258945Sroberto
26258945Sroberto#include <isc/once.h>
27258945Sroberto#include <isc/assertions.h>
28258945Sroberto#include <isc/util.h>
29258945Sroberto
30258945Srobertoisc_result_t
31258945Srobertoisc_once_do(isc_once_t *controller, void(*function)(void)) {
32258945Sroberto	REQUIRE(controller != NULL && function != NULL);
33258945Sroberto
34258945Sroberto	if (controller->status == ISC_ONCE_INIT_NEEDED) {
35258945Sroberto
36258945Sroberto		if (InterlockedDecrement(&controller->counter) == 0) {
37258945Sroberto			if (controller->status == ISC_ONCE_INIT_NEEDED) {
38258945Sroberto				function();
39258945Sroberto				controller->status = ISC_ONCE_INIT_DONE;
40258945Sroberto			}
41258945Sroberto		} else {
42258945Sroberto			while (controller->status == ISC_ONCE_INIT_NEEDED) {
43258945Sroberto				/*
44258945Sroberto				 * Sleep(0) indicates that this thread
45258945Sroberto				 * should be suspended to allow other
46258945Sroberto				 * waiting threads to execute.
47258945Sroberto				 */
48258945Sroberto				Sleep(0);
49258945Sroberto			}
50258945Sroberto		}
51258945Sroberto	}
52258945Sroberto
53258945Sroberto	return (ISC_R_SUCCESS);
54258945Sroberto}
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