1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
 2
 3/*
 4 * Common user-facing libbpf helpers.
 5 *
 6 * Copyright (c) 2019 Facebook
 7 */
 8
 9#ifndef __LIBBPF_LIBBPF_COMMON_H
10#define __LIBBPF_LIBBPF_COMMON_H
11
12#include <string.h>
13
14#ifndef LIBBPF_API
15#define LIBBPF_API __attribute__((visibility("default")))
16#endif
17
18/* Helper macro to declare and initialize libbpf options struct
19 *
20 * This dance with uninitialized declaration, followed by memset to zero,
21 * followed by assignment using compound literal syntax is done to preserve
22 * ability to use a nice struct field initialization syntax and **hopefully**
23 * have all the padding bytes initialized to zero. It's not guaranteed though,
24 * when copying literal, that compiler won't copy garbage in literal's padding
25 * bytes, but that's the best way I've found and it seems to work in practice.
26 *
27 * Macro declares opts struct of given type and name, zero-initializes,
28 * including any extra padding, it with memset() and then assigns initial
29 * values provided by users in struct initializer-syntax as varargs.
30 */
31#define DECLARE_LIBBPF_OPTS(TYPE, NAME, ...)				    \
32	struct TYPE NAME = ({ 						    \
33		memset(&NAME, 0, sizeof(struct TYPE));			    \
34		(struct TYPE) {						    \
35			.sz = sizeof(struct TYPE),			    \
36			__VA_ARGS__					    \
37		};							    \
38	})
39
40#endif /* __LIBBPF_LIBBPF_COMMON_H */