1#ifndef __A_OUT_GNU_H__
2# error "Never use <bits/a.out.h> directly; include <a.out.h> instead."
3#endif
4
5#ifdef __x86_64__
6
7/* Signal to users of this header that this architecture really doesn't
8 support a.out binary format. */
9#define __NO_A_OUT_SUPPORT 1
10
11#endif
12

source code of glibc/sysdeps/unix/sysv/linux/x86/bits/a.out.h