为什么我无法#ifdef stdafx.h? [英] Why am I unable to #ifdef stdafx.h?

问题描述

我正在尝试在.cpp文件中包括2个特定于平台的 stdafx.h 文件，但是当我尝试#ifdef时，编译器并不满意.

I am trying to include 2 platform-specific stdafx.h files in my .cpp file, but the compiler is unhappy when I try to #ifdef it.

#ifdef _WIN32
#include "stdafx.h"
#elif _MAC
#include "MAC/stdafx.h"
#endif

您可能想知道为什么我在Mac代码中使用了stdafx.h，但这并不重要:).

You may wonder why I am using stdafx.h in the Mac code, but that is not important at the moment :).

当我尝试在Windows上编译代码时，收到:致命错误C1018 .我尝试用#ifdef将其他头文件包含在同一文件中，并且编译器很满意.因此，似乎Windows不喜欢stdafx.h为#ifdef版本，或者Windows仅允许 #include stdafx.h 成为文件的第一行.

When I try to compile the code on Windows, I receive: Fatal Error C1018. I tried enclosing other header files with #ifdef in the same file, and the compiler was happy. Therefore, it looks like Windows doesn't like stdafx.h to be #ifdef-ed, or that Windows only allows #include stdafx.h to be the first line in the file.

所以我的问题是，为什么?

So my question is, why?

凯特

推荐答案

当编译器包含预编译的头文件时，它基本上忘记"了该头文件之前的所有内容.因此，您的#elif与#if不再匹配.

When the compiler includes a pre-compiled header, it basically "forgets" anything that came before the header. Thus your #elif isn't matched to a #if anymore.

这篇关于为什么我无法#ifdef stdafx.h?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！