How to get the Volume name from QFileDialog?

Hi All,

I am working in Qt 4.3.3 on my Mac OS.
I have a QFileDialog like this

QFileDialog::getOpenFileName( this, "Open File",":/","");
It returns me some QString.
Now what I want to do is to get the Volume Name or the Drive name of the Selected Path as
if I selected a file on some voulme I should be able to get the Volume name of that path.

If any body knows then please help me.

Thanks
Vishal