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The C and C++ Include Header Files

/usr/include/linux/types.h


$ cat -n /usr/include/linux/types.h

     1	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
     2	#ifndef _LINUX_TYPES_H
     3	#define _LINUX_TYPES_H
     4	
     5	#include <asm/types.h>
     6	
     7	#ifndef __ASSEMBLY__
     8	
     9	#include <linux/posix_types.h>
    10	
    11	#ifdef __SIZEOF_INT128__
    12	typedef __signed__ __int128 __s128 __attribute__((aligned(16)));
    13	typedef unsigned __int128 __u128 __attribute__((aligned(16)));
    14	#endif
    15	
    16	/*
    17	 * Below are truly Linux-specific types that should never collide with
    18	 * any application/library that wants linux/types.h.
    19	 */
    20	
    21	/* sparse defines __CHECKER__; see Documentation/dev-tools/sparse.rst */
    22	#ifdef __CHECKER__
    23	#define __bitwise	__attribute__((bitwise))
    24	#else
    25	#define __bitwise
    26	#endif
    27	
    28	/* The kernel doesn't use this legacy form, but user space does */
    29	#define __bitwise__ __bitwise
    30	
    31	typedef __u16 __bitwise __le16;
    32	typedef __u16 __bitwise __be16;
    33	typedef __u32 __bitwise __le32;
    34	typedef __u32 __bitwise __be32;
    35	typedef __u64 __bitwise __le64;
    36	typedef __u64 __bitwise __be64;
    37	
    38	typedef __u16 __bitwise __sum16;
    39	typedef __u32 __bitwise __wsum;
    40	
    41	/*
    42	 * aligned_u64 should be used in defining kernel<->userspace ABIs to avoid
    43	 * common 32/64-bit compat problems.
    44	 * 64-bit values align to 4-byte boundaries on x86_32 (and possibly other
    45	 * architectures) and to 8-byte boundaries on 64-bit architectures.  The new
    46	 * aligned_64 type enforces 8-byte alignment so that structs containing
    47	 * aligned_64 values have the same alignment on 32-bit and 64-bit architectures.
    48	 * No conversions are necessary between 32-bit user-space and a 64-bit kernel.
    49	 */
    50	#define __aligned_u64 __u64 __attribute__((aligned(8)))
    51	#define __aligned_be64 __be64 __attribute__((aligned(8)))
    52	#define __aligned_le64 __le64 __attribute__((aligned(8)))
    53	
    54	typedef unsigned __bitwise __poll_t;
    55	
    56	#endif /*  __ASSEMBLY__ */
    57	#endif /* _LINUX_TYPES_H */