The C and C++ Include Header Files

/usr/include/endian.h


$ cat -n /usr/include/endian.h

     1	/* Copyright (C) 1992-2024 Free Software Foundation, Inc.
     2	   This file is part of the GNU C Library.
     3	
     4	   The GNU C Library is free software; you can redistribute it and/or
     5	   modify it under the terms of the GNU Lesser General Public
     6	   License as published by the Free Software Foundation; either
     7	   version 2.1 of the License, or (at your option) any later version.
     8	
     9	   The GNU C Library is distributed in the hope that it will be useful,
    10	   but WITHOUT ANY WARRANTY; without even the implied warranty of
    11	   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    12	   Lesser General Public License for more details.
    13	
    14	   You should have received a copy of the GNU Lesser General Public
    15	   License along with the GNU C Library; if not, see
    16	   <https://www.gnu.org/licenses/>.  */
    17	
    18	#ifndef	_ENDIAN_H
    19	#define	_ENDIAN_H	1
    20	
    21	#include <features.h>
    22	
    23	/* Get the definitions of __*_ENDIAN, __BYTE_ORDER, and __FLOAT_WORD_ORDER.  */
    24	#include <bits/endian.h>
    25	
    26	#ifdef __USE_MISC
    27	# define LITTLE_ENDIAN	__LITTLE_ENDIAN
    28	# define BIG_ENDIAN	__BIG_ENDIAN
    29	# define PDP_ENDIAN	__PDP_ENDIAN
    30	# define BYTE_ORDER	__BYTE_ORDER
    31	#endif
    32	
    33	#if defined __USE_MISC && !defined __ASSEMBLER__
    34	/* Conversion interfaces.  */
    35	# include <bits/byteswap.h>
    36	# include <bits/uintn-identity.h>
    37	
    38	# if __BYTE_ORDER == __LITTLE_ENDIAN
    39	#  define htobe16(x) __bswap_16 (x)
    40	#  define htole16(x) __uint16_identity (x)
    41	#  define be16toh(x) __bswap_16 (x)
    42	#  define le16toh(x) __uint16_identity (x)
    43	
    44	#  define htobe32(x) __bswap_32 (x)
    45	#  define htole32(x) __uint32_identity (x)
    46	#  define be32toh(x) __bswap_32 (x)
    47	#  define le32toh(x) __uint32_identity (x)
    48	
    49	#  define htobe64(x) __bswap_64 (x)
    50	#  define htole64(x) __uint64_identity (x)
    51	#  define be64toh(x) __bswap_64 (x)
    52	#  define le64toh(x) __uint64_identity (x)
    53	
    54	# else
    55	#  define htobe16(x) __uint16_identity (x)
    56	#  define htole16(x) __bswap_16 (x)
    57	#  define be16toh(x) __uint16_identity (x)
    58	#  define le16toh(x) __bswap_16 (x)
    59	
    60	#  define htobe32(x) __uint32_identity (x)
    61	#  define htole32(x) __bswap_32 (x)
    62	#  define be32toh(x) __uint32_identity (x)
    63	#  define le32toh(x) __bswap_32 (x)
    64	
    65	#  define htobe64(x) __uint64_identity (x)
    66	#  define htole64(x) __bswap_64 (x)
    67	#  define be64toh(x) __uint64_identity (x)
    68	#  define le64toh(x) __bswap_64 (x)
    69	# endif
    70	#endif
    71	
    72	#endif	/* endian.h */