How to set a window filled the whole screen when we start the window?

[donglongchao <donglongchao 163 com>]

Hi,all
I want to know that when I start a window,how can I set it's default size to fill the whole screen?
I have find some functions to complete this ,but they all need me to pass the width and the height to the 
function as arguments.Is there any function which is able to do this without width or height as arguments?I 
mean that this function should work well in different screen size(1024*800,800*600,etc).
Anyone can help me?Thanks a lot.

Wish you happy.
Dong Longchao