/contrib/ntp/include/isc/once.h

 1/*
 2 * Copyright (C) 2000, 2001  Internet Software Consortium.
 3 *
 4 * Permission to use, copy, modify, and distribute this software for any
 5 * purpose with or without fee is hereby granted, provided that the above
 6 * copyright notice and this permission notice appear in all copies.
 7 *
 8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 9 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
10 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
11 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
13 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
14 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
15 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: once.h,v 1.3 2001/01/09 21:57:56 bwelling Exp $ */
19
20#ifndef ISC_ONCE_H
21#define ISC_ONCE_H 1
22
23#include <isc/result.h>
24
25typedef isc_boolean_t isc_once_t;
26
27#define ISC_ONCE_INIT ISC_FALSE
28
29#define isc_once_do(op, f) \
30	(!*(op) ? (f(), *(op) = ISC_TRUE, ISC_R_SUCCESS) : ISC_R_SUCCESS)
31
32#endif /* ISC_ONCE_H */