1 /*
2  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
3  *
4  * This Source Code Form is subject to the terms of the Mozilla Public
5  * License, v. 2.0. If a copy of the MPL was not distributed with this
6  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
7  *
8  * See the COPYRIGHT file distributed with this work for additional
9  * information regarding copyright ownership.
10  */
11 
12 
13 #ifndef ISC_ONCE_H
14 #define ISC_ONCE_H 1
15 
16 #include <stdbool.h>
17 
18 #include <isc/result.h>
19 
20 typedef bool isc_once_t;
21 
22 #define ISC_ONCE_INIT false
23 
24 #define isc_once_do(op, f) \
25 	(!*(op) ? (f(), *(op) = true, ISC_R_SUCCESS) : ISC_R_SUCCESS)
26 
27 #endif /* ISC_ONCE_H */
28