How can I make a clipper, with cordinates

top- 4 pixels
left- 4 pixels
right - 674 pixels
bottom - 674 pixels

I can't use hWnd because I want to clip just part of the window. I don't know how to use
ddClip->SetClipList(*RGNDATA,0);
I don't know what to pass for RGNDATA

THANKS