How do I do this.....

I am a newbie so please be easy on me

I have C file...which has following for an example.

Code:

extern int globalvar;

void init()
{
   While (something)
   {
      x++
    }
    globalvar = x;
}

int getglobalvar (void)
{
   return(globalvar);
}

Now I have a C++ file.....

Which I have a function

Code:

void needGlobalvar()
{
  int y = getglobalvar() 
}

basically I will be then calling this function needGlobalvar in another C++ else....whats the best way I could move the function

Code:

int getglobalvar (void)
{
   return(globalvar);
}

to C++ and still have the access to correct information set in the C function for the globalvar

One of my friends said to make the globalvar a singleton and access it so this way it will be safe....could someone please help me with how I could use the sigleton...because I have not done that before.....

Somewhere in your C++ code, before you try to call the function, you need

Code:

extern "C" int getglobalvar (void);

Then you just compile everything, making sure you compile main() using C++, and you should be good.

Thanks Salem,

Could you please kindly....show me the flow with this change? It will help me to learn and understand...

Thanks much.

There isn't anything else to show - that's it, just that one line, placed at a suitable point in your C++ code (perhaps an included header file).

This is good information, if you're mixing C and C++.
[32] How to mix C and C++ ..Updated!.., C++ FAQ

Originally Posted by Salem

There isn't anything else to show - that's it, just that one line, placed at a suitable point in your C++ code (perhaps an included header file).

This is good information, if you're mixing C and C++.
[32] How to mix C and C++ ..Updated!.., C++ FAQ

Salem again...thanks.....
But I would like to move the

Code:

int getglobalvar (void)
{
   return(globalvar);
}

to C++ and make it a C++ function....

Hey, it's entirely up to you.

Either you do extern "C" on a function of your choice, or you do extern "C" on the global variable.

I don't understand why you haven't actually tried this for yourself yet, rather than trying to get me to do it for you (not going to happen).