c++ - 你如何为具有继承的 C++ 类编写 C 包装器

Question

我只是想知道是否有办法为具有继承的 C++ 类创建一个 C 包装器 API。

考虑以下几点:

class sampleClass1 : public sampleClass{

  public:
    int get() { return this.data *2; };
    void set(int data);
}


class sampleClass : public sample{

  public:
   int get() { return this.data; }
   void set(int data) {this.data = data; }
}

class sample {

 public:
   virtual int get();
   virtual void set(int data);

 private:
   int data;

}

我将如何包装 sampleClass1 以使其在 c 上下文中工作？？？

谢谢，

Answer 1

首先，您的示例 应该真正获得适当的虚拟 dtor。

接下来，只需为作为接口(interface)一部分的每个函数添加一个具有 C 绑定(bind)的自由函数，简单地委托(delegate):

“示例.h”

#ifdef __cplusplus
extern "C" {
#endif
typedef struct sample sample;
sample* sample_create();
sample* sample_create0();
sample* sample_create1();
void sample_destroy(sample*);
int sample_get(sample*);
void sample_set(sample*, int);
#ifdef __cplusplus
}
#endif

“示例-c.cpp”

#include "sample.h" // Included first to find errors
#include "sample.hpp" // complete the types and get the public interface

sample* sample_create() {return new sample;}
sample* sample_create0() {return new sampleClass;}
sample* sample_create1() {return new sampleClass1;}
void sample_destroy(sample* p) {delete p;}
int sample_get(sample* p) {return p->get();}
void sample_set(sample* p, int x) {p->set(x);

“示例.hpp”

// Your C++ header here, with class definition

“示例.cpp”

#include "sample.hpp" // Included first to find errors
// Implement the class here