在 glibc 中找不到 iso646.h

Question

我下载了多个版本的 glibc，即 2.18、2.19、2.20、2.23，我试图找到文件 iso646.h 但找不到。我认为它是 glibc 的标准部分，所以它应该在那里。有谁知道为什么它不存在？

但是，我在本地机器的/usr/lib/gcc 目录中找到了它。所以我假设它是用 gcc 安装的。但我仍然不知道为什么我在 glibc 源代码中找不到它。我正在粘贴我在下面找到的内容:

/* Copyright (C) 1997-2014 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
GNU General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and 
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see 
<http://www.gnu.org/licenses/>.  */  

/*
 * ISO C Standard:  7.9  Alternative spellings  <iso646.h>
 */

#ifndef _ISO646_H
#define _ISO646_H

#ifndef __cplusplus
#define and     &&  
#define and_eq  &=
#define bitand  &
#define bitor   |
#define compl   ~
#define not     !
#define not_eq  !=
#define or      ||
#define or_eq   |=
#define xor     ^
#define xor_eq  ^=
#endif

#endif

编辑: 我在(从 gnu.org)下载的每个 glibc 源中找到的唯一文件(有点像 iso646.h)是 conform/data/iso646.h-data 看起来像这样:

#if !defined ISO && !defined POSIX && !defined XPG3 && !defined XPG4
macro and 
macro and_eq
macro bitand
macro bitor
macro compl
macro not 
macro not_eq
macro or
macro or_eq
macro xor 
macro xor_eq

#if !defined ISO && !defined ISO99 && !defined ISO11
allow *_t 
#endif
#endif

但是因为我不知道macro 在这里是如何定义的，或者它是在哪里定义的，所以这个文件对我来说是不可理解的。

Answer 1

该文件不是 libc 的一部分，而是编译器。

https://gcc.gnu.org/onlinedocs/gccint/Headers.html

$ find /|grep iso646.h
/usr/lib/gcc/x86_64-linux-gnu/4.8/include/iso646.h
/usr/lib/gcc/x86_64-linux-gnu/4.6/include/iso646.h