调用＆QUOT; C ++＆QUOT;类的成员函数从＆QUOT; C＆QUOT; code [英] Calling "C++" class member function from "C" code

问题描述

我们如何可以调用CC ++类的成员函数code？

How can we call "C++" class member functions in 'C" code ?

我的的.cpp，在我与其中包括了一些其他的帮助CPP / h的文件，成员函数和相应的的.h头文件中定义的一些类两个文件。

I have two files .cpp, in which I have defined some classes with member functions and corresponding ".h" files which has included some other helping cpp/h files.

现在我要调用的CPP文件中的C文件中的这些功能​​。
我该怎么办呢？

Now I want to call these functionality of CPP files in "C" file. How can I do it?

推荐答案

C有没有 thiscall 概念。 C调用约定不直接调用允许C ++对象的成员函数。

C has no thiscall notion. The C calling convention doesn't allow directly calling C++ object member functions.

为此，您需要提供一个封装API在你的C ++对象，即需要在这个指针明确，而不是含蓄。

Therefor, you need to supply a wrapper API around your C++ object, one that takes the this pointer explicitly, instead of implicitly.

例如：

// C.hpp
// uses C++ calling convention
class C {
public:
   bool foo( int arg );
};

C包装API：

C wrapper API:

// api.h
// uses C calling convention
#ifdef __cplusplus
extern "C" {
#endif

void* C_Create();
void C_Destroy( void* thisC );
bool C_foo( void* thisC, int arg );

#ifdef __cplusplus
}
#endif

您的API将在C ++中实现：

Your API would be implemented in C++:

#include "api.h"
#include "C.hpp"

void* C_Create() { return new C(); }
void C_Destroy( void* thisC ) {
   delete static_cast<C*>(thisC);
}
bool C_foo( void* thisC, int arg ) {
   return static_cast<C*>(thisC)->foo( arg );
}

有很多伟大的文档在那里了。第一个<一href=\"http://www.google.be/search?sourceid=chrome&ie=UTF-8&q=wrapping+C%2B%2B+object+into+C\">I碰到可以在这里找到 。

There is a lot of great documentation out there, too. The first one I bumped into can be found here.

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