extern "C" in DLL with classes

[vivendi]

I want to create a DLL file but i'm not sure what to do. First i'll try to explain what i have.

In my dll i have the dllMain function. But i also have classes with public and private members/functions. What i want is that other programming languages have access to my functions.
So i compile a dll in C++, and someone else who is coding in C# should be able to add my DLL to this project and have access to those classes -> which gives him access to the functions.

But there seems to be a special way of creating a dll if i want to do such a thing. I know i have to use the extern "C" declaration. But how exactly do i do this?? Do i just encapsulate my classes around an extern "C" declaration? Like so:

Code:

extern "C" {
class cTest
{
public:
//functions here
}
}

So would this be enough?? I also read somewhere that i can only use structs?? Or can i use classes too this way??

Well anyway, any information is more than welcome!

Thanks for any help!