bind/lib/isc/win32/once.c

/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* $Id: once.c,v 1.3 2000/02/03 23:08:11 halley Exp $ */

/* Principal Authors: DCL */

#include <windows.h>

#include <isc/once.h>
#include <isc/assertions.h>

isc_result_t
isc_once_do(isc_once_t *controller, void(*function)(void))

{
	REQUIRE(controller != NULL && function != NULL);

	if (controller->status == ISC_ONCE_INIT_NEEDED) {	
	
		if (InterlockedDecrement(&controller->counter) == 0) {
			if (controller->status == ISC_ONCE_INIT_NEEDED) {
				function();
				controller->status = ISC_ONCE_INIT_DONE;
			}
		} else {
			while (controller->status == ISC_ONCE_INIT_NEEDED) {
				/*
				 * Spin wait.
				 */
			}
		}
	}

	return (ISC_R_SUCCESS);
}