Class Template

Class template is used to provide a programming experience similar to object-oriented programming. The module provides several macros to implement object-oriented programming style.

This module is not supported in the MSVC.

Header file

#include "mln_class.h"

Module

class

Macros

class

class(type, constructor, destructor, ...);

Description: Defines a class with the following macro parameters:

• type: The type name of the class, i.e., the class name.
• constructor: The constructor of the class. The first parameter must be a void *, which is actually a pointer to the object of this class. However, due to compiler processing order and issues with function and struct definitions, the type specified by type cannot be directly used here. The remaining parameters and return value type are user-defined. The return value of the constructor will be ignored.
• destructor: The destructor of the class. Similar to constructor, the first parameter must be a void *, and the remaining parameters are user-defined, with the return value being ignored.
• ...: The member definitions of the class, enclosed in {}.

Return value: None.

new

new(type, ...);

Description: Instantiate an object of a class. type is the name of the class, and ... are the arguments corresponding to the parameters in the constructor, excluding the first parameter.

Return value: Returns a pointer to the object if successful, otherwise returns NULL. Note that a failure in the constructor does not result in a NULL return value, as the return value of the constructor is ignored.

delete

delete(o, ...);

Description: Free an object. o is a pointer to the object, and ... are the remaining arguments in the destructor, excluding the first parameter.

Return value: None

Example

#include "mln_class.h"
#include <stdio.h>

typedef void (*func_t)(void *);
static void _constructor(void *o, int a, func_t func);
static void _destructor(void *o);

class(F, _constructor, _destructor, {
    int a;
    func_t f;
});

static void fcall(void *o)
{
    printf("in function call\n");
}

static void _constructor(void *o, int a, func_t func)
{
    printf("constructor\n");
    F *f = (F *)o;
    f->a = a;
    f->f = func;
}

static void _destructor(void *o)
{
    printf("destructor\n");
}

int main(void)
{
     F *f = new(F, 1, fcall);
     printf("%d\n", f->a);
     f->f(f);
     delete(f);
     return 0;
}

Note that function typedef, and constructor and destructor declarations must be given before the class macro. All function definitions must come after the class macro.