当包含C库时，什么时候应该在“extern”C“中包含 [英] When should you wrap include in `extern "C"` when including a C Library

问题描述

我理解，当您在 c ++ 项目中包含 c 标题时，必须用 externC，因为 c ++ 和 c 功能。 c 将使用名称来标识函数， c ++ 必须使用名称和参数来满足函数重载。

I understand that when you include a c header in your c++ project you must wrap it with extern "C" because c++ and c have two different ways of identifying function. c will use the name to identify a function and c++ must use the name and the parameters to satisfy function overloading.

我不明白为什么有 c 标题，不需要包装 externC like windows.h

What I don't understand is why are there are c headers that don't require to be wrapped in extern "C" like windows.h??

推荐答案

通常，在 externC中包装C头不是一个好主意。标题可能包括在您执行此操作时断开的其他文件。在C ++中使用的设计的C标头将适当处理 externC，而无需执行任何操作。典型代码：

In general, wrapping a C header in extern "C" is not a good idea. The header might include other files that break when you do this. A C header that is designed to be used in C++ will handle extern "C" appropriately, without you having to do anything. Typical code:

#ifndef MY_HEADER_INCLUDE_GUARD
#define MY_HEADER_INCLUDE_GUARD

#ifdef __cplusplus
extern "C" {
#endif

/* C callable stuff goes here */

#ifdef __cplusplus
}
#endif

#endif /* MY_HEADER_INCLUDE_GUARD */

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