Hi all,

What does "virtual void" mean?

I'm trying to do some basic qt/KDE programming..

Yes I know, this isn't the programming forum.

best regards,
Cyth

virtual specifies the function type.
void is a datatype,
eg.

class myclass
{
public:
virtual void Func(){}
};

It means you've written yourself into an unyielding black hole of code in which escape is unachievable!

i like it when they don't realise their asking the question in the wrong forum..and don't admit it, it makes the person asking the question seem more intelligent.

No, really; what does virtual mean?

/Cyth

The virtual keyword is used to make a function virtual. If a class is derived from a base class with and the function is overwritten then if it's virtual then the function from the derived class will be run instead of the one from the base class.
That probably just sounds even more confusing because I'm not good at explaining these kind of things. If you want a full explanation try downloading the book Thinking in C++ from Bruce Eckel. In chapter 15 it has a complete explanation of virtual functions.

http://bruceeckel.com

Here is the simple example of virtual function which is perhaps the easiest way to understand what it means.

class Foo {
public:
virtual void A;
};

class Foo1: public Foo {
public:
void A;
};

void Foo::A {
printf("\nHello world from Foo");
}

void Foo1::A {
printf("\nHello world from Foo1");
}

int main()
{
Foo *x = new Foo1();
x->A;
}

The result should be "Hello world from Foo1" even though we declared the x as Foo. This works only for the objects which are created on the heap (the new keyword). This concept is called polimorphism. By declaring function as virtual compiler calls the function from the subclass even though that pointer type is base class pointer. For more datailed information read some books.

Thanks!

/Cyth