Re: Objectizing C Code

From: (Carl Barron)
Mon, 26 Feb 2007 21:21:03 CST
Robby <> wrote:

Here's a brainteaser:

I have some legacy C code that I cannot modify for various reasons. I
would like to be able to wrap this code into a C++ class so that I can
create multiple objects to interact with.

To simplify, here's some code:

foo.h (Can't modify):

#ifndef _FOO_H_
#define _FOO_H_

#if defined(TEST1) && defined(TEST2)
#error "Cannot define both TEST1 and TEST2"

#ifdef TEST1
#define OUTVAR 1
#elif defined(TEST2)
#define OUTVAR 2
#error "Need TEST1 or TEST2"

extern int testInt;

void testFunc();


foo.c (Cannot modify):

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

int testInt;

void testFunc() {
    testInt = OUTVAR;
    printf("%d\n", testInt);


// wrapper.h"
extern "C"
#include "foo.h"

template <int N>
struct wrapper
    int var;
    void operator () ()
       var = testInt;


    wrapper<OUTVAR> functor;
    int local_copy = functor.var;

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