The C and C++ Include Header Files

/usr/include/x86_64-linux-gnu/asm/unistd.h


$ cat -n /usr/include/x86_64-linux-gnu/asm/unistd.h

     1	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
     2	#ifndef _ASM_X86_UNISTD_H
     3	#define _ASM_X86_UNISTD_H
     4	
     5	/*
     6	 * x32 syscall flag bit.  Some user programs expect syscall NR macros
     7	 * and __X32_SYSCALL_BIT to have type int, even though syscall numbers
     8	 * are, for practical purposes, unsigned long.
     9	 *
    10	 * Fortunately, expressions like (nr & ~__X32_SYSCALL_BIT) do the right
    11	 * thing regardless.
    12	 */
    13	#define __X32_SYSCALL_BIT	0x40000000
    14	
    15	# ifdef __i386__
    16	#  include <asm/unistd_32.h>
    17	# elif defined(__ILP32__)
    18	#  include <asm/unistd_x32.h>
    19	# else
    20	#  include <asm/unistd_64.h>
    21	# endif
    22	
    23	#endif /* _ASM_X86_UNISTD_H */