你如何为继承的c ++类编写一个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c包装API。

请考虑以下事项：

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;

}

如何包装sampleClass1以使其在c上下文中工作？

感谢，

Answer 1

首先，您的sample应该真正得到一个合适的virtual dtor。

接下来，只需为每个作为界面一部分的函数添加一个带C-binding的自由函数，只需委托：

“sample.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

“样品-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);

“sample.hpp”

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

“sample.cpp的”

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