Developing Yed objects - Inheriting the only interface from a Yed object

Yed scenario allows inheritance of the only object interface, similar to inheritance from an 'abstract class' in C++ scenario. Using the same example introduced in 'Inheriting all entities from a Yed object' paragraph, let's see how.

This is Myclass object declaration:

typedef struct {
char PRIVATE(protected); 
PUBLIC int (*My_Func)(void *);    
PUBLIC char my_attr;            
} Myclass;

Assuming Myclass is an object without any method implementation, as an 'abstract class'. Cderiv will inherit the only Myclass interface:

typedef struct {
// FROM Myclass declaration -----------
char PRIVATE(protected); 
PUBLIC int (*My_Func)(void *);    
PUBLIC char my_attr; 
// Declaration of Cderiv entities -----
int PRIVATE(siFoo);
PUBLIC int (*Foo_Func)(void *);
} Cderiv;

The constructor of Cderiv is the same:

Cderiv * _Cderiv(void) {
Cderiv *this=malloc(sizeof(Cderiv));
if(this!=NULL) {
  // INIT from Myclass constructor -----------
  // INIT for Cderiv entities -----------
return this;

Also the destructor:

void _DMyClass(void *pvT) {

In this case, the method My_Func, related to Myclass object in terms of interface, does not have any implementation. Thus, we build a simple implementation of it:

/**** FUNCTION PROTOTYPES ( in Cderiv header file declaration ) ****/
int My_Func(void *);
/**** METHOD IMPLEMENTATION ( in Cderiv file definition ) ****/
int My_Func(void *pVWork) {
Cderiv *this=pvWork;        // 'THIS' POINTER OF THE INSTANCE!!!
printf("The protected member value is [%d]\n", this->PRIVATE(protected));
return 0;

In this case, pointer 'this' is related to Cderiv object, because the implementation of this method is specific to Cderiv object ( Myclass has declared the only interface ).

The example of code using Cderiv is the same:

#include "yedstd.h"
#include "cderiv.h"

Cderiv *cFoo;

if(cFoo!=NULL) {
  cFoo->My_Func(cFoo); // interface from Myclass, implementation from Cderiv
  cFoo->Foo_Func(cFoo);   // method specific of Cderiv