>I am trying to write a simple function in Visual C++ 6.0 (DLL) which add
>2 variables that I send from Visual FoxPro 6.0, ADD them together and return the value back to VFP. How I can do this ? (Please give me some sample code)

Disclaimer: I'm not booted on a partition that has VC++ 6.0 installed, so this is off the top of my head.

Create a DLL, and when prompted by the wizard, select "DLL that exports some symbols". This will give you a template of how to return a value (one of the functions returns 42. Get it?) Create your own function as follows:

int MyFunction(int FirstNumber, int SecondNumber)
{
    return FirstNumber + SecondNumber;
}

Create a .DEF file in the project. In that file, you need to specify that you're exporting MyFunction using the EXPORTS statement. See the MSDN on how to do this (this link gives an example). Compile and you're done. I think that there's also an example floating around in the files section or the FAQ.