使用外部"C“的潜在缺点是什么？

Question

我读过

• When to use extern "C" in C++?
• In C++ source, what is the effect of extern "C"?
• Why do we need extern "C"{ #include } in C++?

但是，有一个问题我还没有找到答案:使用extern "C" (例如，在尽可能多的函数上)是否存在(可能的，未来的)缺点？

更具体地说:将extern "C"添加到只使用C功能的函数中有什么缺点吗?换句话说，那些不使用@k-5中列出的功能的函数有什么缺点？

Answer 1

缺点是，您只能在extern "C"函数的接口中使用C函数也可用的特性。

这意味着：

1. you can't use default values for function arguments,
2. you can't use reference arguments,
3. you can't pass C++ classes by value (including smart pointers),
4. you can't pass `enum class` arguments,
5. you can't pass `bool` without converting it to `int`,
6. you can't overload such functions, and probably more that I can't recall at the moment.