once.c revision 285612 
160107Sobrien/*
22786Ssos * Copyright (C) 2004, 2007  Internet Systems Consortium, Inc. ("ISC")
32786Ssos * Copyright (C) 1999-2001  Internet Software Consortium.
42786Ssos *
52786Ssos * Permission to use, copy, modify, and/or distribute this software for any
62786Ssos * purpose with or without fee is hereby granted, provided that the above
72786Ssos * copyright notice and this permission notice appear in all copies.
82786Ssos *
92786Ssos * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
102786Ssos * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
112786Ssos * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
122786Ssos * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
132786Ssos * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
142786Ssos * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
152786Ssos * PERFORMANCE OF THIS SOFTWARE.
162786Ssos */
172786Ssos
1838140Syokota/* $Id: once.c,v 1.12 2007/06/18 23:47:49 tbox Exp $ */
192786Ssos
206867Sache/* Principal Authors: DCL */
214686Sache
222786Ssos#include <config.h>
232786Ssos
242786Ssos#include <windows.h>
252786Ssos
262786Ssos#include <isc/once.h>
272786Ssos#include <isc/assertions.h>
282786Ssos#include <isc/util.h>
292786Ssos
302786Ssosisc_result_t
312786Ssosisc_once_do(isc_once_t *controller, void(*function)(void)) {
322786Ssos	REQUIRE(controller != NULL && function != NULL);
332786Ssos
342786Ssos	if (controller->status == ISC_ONCE_INIT_NEEDED) {
352786Ssos
362786Ssos		if (InterlockedDecrement(&controller->counter) == 0) {
372786Ssos			if (controller->status == ISC_ONCE_INIT_NEEDED) {
382786Ssos				function();
392786Ssos				controller->status = ISC_ONCE_INIT_DONE;
402786Ssos			}
412786Ssos		} else {
422786Ssos			while (controller->status == ISC_ONCE_INIT_NEEDED) {
432786Ssos				/*
442786Ssos				 * Sleep(0) indicates that this thread
452786Ssos				 * should be suspended to allow other
462786Ssos				 * waiting threads to execute.
472786Ssos				 */
482786Ssos				Sleep(0);
492786Ssos			}
502786Ssos		}
512786Ssos	}
522786Ssos
532786Ssos	return (ISC_R_SUCCESS);
542786Ssos}
552786Ssos