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c5c0fdbe DDT |
1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
2 | #ifndef _LINUX_STDDEF_H | |
3 | #define _LINUX_STDDEF_H | |
4 | ||
5 | ||
6 | ||
7 | #ifndef __always_inline | |
8 | #define __always_inline __inline__ | |
9 | #endif | |
10 | ||
11 | /** | |
12 | * __struct_group() - Create a mirrored named and anonyomous struct | |
13 | * | |
14 | * @TAG: The tag name for the named sub-struct (usually empty) | |
15 | * @NAME: The identifier name of the mirrored sub-struct | |
16 | * @ATTRS: Any struct attributes (usually empty) | |
17 | * @MEMBERS: The member declarations for the mirrored structs | |
18 | * | |
19 | * Used to create an anonymous union of two structs with identical layout | |
20 | * and size: one anonymous and one named. The former's members can be used | |
21 | * normally without sub-struct naming, and the latter can be used to | |
22 | * reason about the start, end, and size of the group of struct members. | |
23 | * The named struct can also be explicitly tagged for layer reuse, as well | |
24 | * as both having struct attributes appended. | |
25 | */ | |
26 | #define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \ | |
27 | union { \ | |
28 | struct { MEMBERS } ATTRS; \ | |
29 | struct TAG { MEMBERS } ATTRS NAME; \ | |
efb91426 | 30 | } ATTRS |
c5c0fdbe | 31 | |
efb91426 DHB |
32 | #ifdef __cplusplus |
33 | /* sizeof(struct{}) is 1 in C++, not 0, can't use C version of the macro. */ | |
34 | #define __DECLARE_FLEX_ARRAY(T, member) \ | |
35 | T member[0] | |
36 | #else | |
c5c0fdbe DDT |
37 | /** |
38 | * __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union | |
39 | * | |
40 | * @TYPE: The type of each flexible array element | |
41 | * @NAME: The name of the flexible array member | |
42 | * | |
43 | * In order to have a flexible array member in a union or alone in a | |
44 | * struct, it needs to be wrapped in an anonymous struct with at least 1 | |
45 | * named member, but that member can be empty. | |
46 | */ | |
47 | #define __DECLARE_FLEX_ARRAY(TYPE, NAME) \ | |
48 | struct { \ | |
49 | struct { } __empty_ ## NAME; \ | |
50 | TYPE NAME[]; \ | |
51 | } | |
52 | #endif | |
da3c22c7 TH |
53 | |
54 | #ifndef __counted_by | |
55 | #define __counted_by(m) | |
56 | #endif | |
efb91426 DHB |
57 | |
58 | #endif /* _LINUX_STDDEF_H */ |