结尾的 _ $ c $可以添加c>以避免与用户定义的标识符冲突。例如，您可能有一个名为 get.h 的头文件，并且同时可以想象有一个名为 GET_H 。因此，在 get.h 中使用 GET_H 作为包含保护很容易导致问题。

The trailing _ might be added to avoid collision with user-defined identifiers. For example, you might have a header file named get.h and at the same time you can conceivably have your own macro (or variable, or function) named GET_H. So, using GET_H for include guard in get.h would easily lead to problems.

出于相同的目的，标准库头文件可能会使用前导 _ 为其内部宏命名-避免名称与用户定义冲突身份标识。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 _ 不能用于包含防护的名称。

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.

因此，Eclipse出于相同的目的决定使用跟踪 _ 。它提供了合理的保护级别，以防止名称冲突，并且不违反语言规范的要求。

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.