1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux 1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI_LINUX_STDDEF_H 2 #ifndef _UAPI_LINUX_STDDEF_H
3 #define _UAPI_LINUX_STDDEF_H 3 #define _UAPI_LINUX_STDDEF_H
4 4
5 #include <linux/compiler_types.h> 5 #include <linux/compiler_types.h>
6 6
7 #ifndef __always_inline 7 #ifndef __always_inline
8 #define __always_inline inline 8 #define __always_inline inline
9 #endif 9 #endif
10 10
11 /** 11 /**
12 * __struct_group() - Create a mirrored named 12 * __struct_group() - Create a mirrored named and anonyomous struct
13 * 13 *
14 * @TAG: The tag name for the named sub-struct 14 * @TAG: The tag name for the named sub-struct (usually empty)
15 * @NAME: The identifier name of the mirrored 15 * @NAME: The identifier name of the mirrored sub-struct
16 * @ATTRS: Any struct attributes (usually empt 16 * @ATTRS: Any struct attributes (usually empty)
17 * @MEMBERS: The member declarations for the m 17 * @MEMBERS: The member declarations for the mirrored structs
18 * 18 *
19 * Used to create an anonymous union of two st 19 * Used to create an anonymous union of two structs with identical layout
20 * and size: one anonymous and one named. The 20 * and size: one anonymous and one named. The former's members can be used
21 * normally without sub-struct naming, and the 21 * normally without sub-struct naming, and the latter can be used to
22 * reason about the start, end, and size of th 22 * reason about the start, end, and size of the group of struct members.
23 * The named struct can also be explicitly tag 23 * The named struct can also be explicitly tagged for layer reuse, as well
24 * as both having struct attributes appended. 24 * as both having struct attributes appended.
25 */ 25 */
26 #define __struct_group(TAG, NAME, ATTRS, MEMBE 26 #define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
27 union { \ 27 union { \
28 struct { MEMBERS } ATTRS; \ 28 struct { MEMBERS } ATTRS; \
29 struct TAG { MEMBERS } ATTRS N 29 struct TAG { MEMBERS } ATTRS NAME; \
30 } ATTRS 30 } ATTRS
31 31
32 #ifdef __cplusplus 32 #ifdef __cplusplus
33 /* sizeof(struct{}) is 1 in C++, not 0, can't 33 /* sizeof(struct{}) is 1 in C++, not 0, can't use C version of the macro. */
34 #define __DECLARE_FLEX_ARRAY(T, member) \ 34 #define __DECLARE_FLEX_ARRAY(T, member) \
35 T member[0] 35 T member[0]
36 #else 36 #else
37 /** 37 /**
38 * __DECLARE_FLEX_ARRAY() - Declare a flexible 38 * __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union
39 * 39 *
40 * @TYPE: The type of each flexible array elem 40 * @TYPE: The type of each flexible array element
41 * @NAME: The name of the flexible array membe 41 * @NAME: The name of the flexible array member
42 * 42 *
43 * In order to have a flexible array member in 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 anonym 44 * struct, it needs to be wrapped in an anonymous struct with at least 1
45 * named member, but that member can be empty. 45 * named member, but that member can be empty.
46 */ 46 */
47 #define __DECLARE_FLEX_ARRAY(TYPE, NAME) 47 #define __DECLARE_FLEX_ARRAY(TYPE, NAME) \
48 struct { \ 48 struct { \
49 struct { } __empty_ ## NAME; \ 49 struct { } __empty_ ## NAME; \
50 TYPE NAME[]; \ 50 TYPE NAME[]; \
51 } 51 }
52 #endif 52 #endif
53 53
54 #ifndef __counted_by 54 #ifndef __counted_by
55 #define __counted_by(m) 55 #define __counted_by(m)
56 #endif 56 #endif
57 57
58 #ifndef __counted_by_le 58 #ifndef __counted_by_le
59 #define __counted_by_le(m) 59 #define __counted_by_le(m)
60 #endif 60 #endif
61 61
62 #ifndef __counted_by_be 62 #ifndef __counted_by_be
63 #define __counted_by_be(m) 63 #define __counted_by_be(m)
64 #endif 64 #endif
65 65
66 #endif /* _UAPI_LINUX_STDDEF_H */ 66 #endif /* _UAPI_LINUX_STDDEF_H */
67 67
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