eclipse自动生成的.h文件守卫
在 Eclipse 中，当创建 C++ 类时，会自动生成带有保护 XXXX_H_ 的 .h 文件。根据我有限的经验，守卫始终采用 XXXX_H 的形式，而没有尾随 _。
所以，我只是好奇为什么 _ 在那里。
提前致谢。
In eclipse, when a c++ class is created, .h file's auto-generated with guard XXXX_H_. In my limited, little experience, the guard is always be in the form of XXXX_H without the trailing _.
So, I'm just curious and wondering why the _ is over there.
Thanks in advance.
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如果您使用相当现代的编译器，则可以用更优雅的指令
#pragma Once替换这些保护。要修改 Eclipse CDT 中的标头模板，请转到“Window/Preferences/C++/Code Templates/Files/ C++ 头文件/默认 C++ 头模板”并放在那里
之后，您的新 h 文件将从如下所示开始：
If you use a reasonably modern compiler, you can replace these guards with more elegant directive
#pragma onceTo modify the header's template in Eclipse CDT, go to "Window/Preferences/C++/Code Templates/Files/C++ Header File/Default C++ header template" and put there
After that your new h files will start from something like this:
可能会添加尾随
_以避免与用户定义的标识符发生冲突。例如，您可能有一个名为get.h的头文件，同时您也可以拥有自己的名为GET_H的宏（或变量或函数）。因此，在get.h中使用GET_H进行包含保护很容易导致问题。标准库头文件可能会使用前导
_来命名其内部宏，以达到相同的目的 - 避免与用户定义的标识符发生名称冲突。因此，语言规范明确禁止以_和大写字母开头的用户定义标识符。出于同样的原因，前导_不能在包含防护的名称中使用。因此，Eclipse 决定使用 尾随
_来达到同样的目的。它提供了合理级别的名称冲突保护，并且不违反语言规范的要求。The trailing
_might be added to avoid collision with user-defined identifiers. For example, you might have a header file namedget.hand at the same time you can conceivably have your own macro (or variable, or function) namedGET_H. So, usingGET_Hfor include guard inget.hwould easily lead to problems.The standard library header files might use a leading
_to name its internal macros for the very same purpose - to avoid name collision with user-defined identifiers. For that reason, the language specification explicitly prohibits user-defined identifiers that begin with_and a capital letter. And for the very same reason, the leading_cannot be used in the names of include guards.So, Eclipse decided to use a trailing
_for the very same purpose. It provides a reasonable level of protection from name collisions and does not violate the requirements of language specification.包含防护的名称是什么并不重要，只要它在所有头文件中是唯一的即可。
XXXX_H_很常见，XXXX_H也是如此。有时会使用 GUID。It doesn't matter what the name of the inclusion guard is, so long as it is unique across all header files.
XXXX_H_is common, as isXXXX_H. GUIDs are occasionally used.名称无关紧要，只需唯一即可。我的猜测是，添加它是为了减少与用户创建的定义发生冲突的可能性。
The name is irrelevant, it just needs to be unique. My guess is that it was added to make it less likely to have a collision with user-created defines.