C++ 包含和导入的区别
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C++ include and import difference
提问by Marius
What is the difference between #includeand #importin C++?
在 C++ 中#include和#import在 C++ 中有什么区别？
采纳答案by Head Geek
#importis a Microsoft-specific thing, apparently for COM or .NET stuff only.
#import是特定于 Microsoft 的东西，显然仅适用于 COM 或 .NET 的东西。
#includeis a standard C/C++ preprocessor statement, used for including header (or occasionally other source code) files in your source code file.
#include是标准的 C/C++ 预处理器语句，用于在您的源代码文件中包含头文件（或偶尔的其他源代码）文件。
回答by Brian R. Bondy
Import in VC++:#importis for type libraries or .tlbs (COM stuff).
在 VC++ 中导入：#import用于类型库或 .tlbs（COM 内容）。
The content of the type library is converted into C++ classes, mostly describing the COM interfaces for you automatically, and then it is included into your file.
类型库的内容被转换为 C++ 类，主要是自动为您描述 COM 接口，然后将其包含到您的文件中。
The #importdirective was introduced by Microsoft as an extension to the C++ language. You can read about it at this MSDN article.
该#import指令由 Microsoft 作为 C++ 语言的扩展引入。您可以在这篇 MSDN 文章中阅读它。
The #importdirective is also used with .NET / CLI stuff.
该#import指令还用于 .NET/CLI 的东西。
Import in gcc:The import in gcc is different from the import in VC++. It is a simple way to include a header at most once only. (In VC++ and GCC you can do this via #pragmaonce as well)
在 gcc 中导入：gcc 中的导入与 VC++ 中的导入不同。这是一种最多只包含一次标题的简单方法。（在 VC++ 和 GCC 中，您也可以通过#pragma一次执行此操作）
The #importdirective was officially undeprecated by the gcc team in version 3.4 and works fine 99% of the time in all previous versions of gcc which support
该#import指令在 3.4 版中被 gcc 团队正式弃用，并且在所有支持
Include:#includeis for mostly header files, but to prepend the content to your current file. #includeis part of the C++ standard. You can read about it at this MSDN article.
Include:#include主要用于头文件，但将内容添加到当前文件中。#include是 C++ 标准的一部分。您可以在这篇 MSDN 文章中阅读它。
回答by thatha
#importis overall a solutionto the usual
#import总体上是对通常的解决方案
#ifndef ...
#define ...
#include ...
#endif
work-around. #importincludes a file only if it hasn't been included before.
解决办法。#import仅当以前未包含文件时才包含该文件。
It might be worth noting that Apple's Objective-C also uses #importstatements.
值得注意的是，Apple 的 Objective-C 也使用了#import语句。
回答by Don Wakefield
importwas also one of the keywords associated with n2073, Modules in C++, proposed to the language committee by Daveed Vandevoorde in September 2006. I'm not enough of a language geek to know if that proposal was definitively shelved or if it's awaiting an implementation (proof of concept) from the author or someone else...
import也是与n2073相关的关键字之一，C++ 中的模块，由 Daveed Vandevoorde 于 2006 年 9 月向语言委员会提出。我不是一个语言极客，无法知道该提案是否被最终搁置或是否正在等待实施（概念证明）来自作者或其他人......
回答by Mike Godin
Please note that in gcc 4.1, #importisdeprecated. If you use it, you will get warning:
请注意，在 gcc 4.1 中，#import已弃用。如果你使用它，你会得到警告：
#importis a deprecated GCC extension
#import不推荐使用的 GCC 扩展
