Where is GdkWindow defined

[Jamie Kao <accountofjk gmail com>]

Hello, this is the first time I use the mailing list, so i'm not sure if 
this is the place to ask for this kind of help, or am i know if I am 
using the mailing list right.
Don't flame...

Anyways, I've been trying to find the file where GdkWindow is defined 
in. I checked GdkWindow.h and GdkWindow.c. Non of them or their include 
files tell me where it is.

does anyone know of the locations?