Plz help!!!!Trimmed surface Bounding Box

I have created a nurb Surface using gluNurbsSurface and used gluNurbsCurve and gluPwlCurves for creating trimmed Nurbs Surface,But Now I want to calculate the Bounding Box of the Trimmed surface.
Thanks in Advance!!!

Take a look at gluNurbsCallback, you can set it up in a way that instead of rendering your NURB surface a callback is called for each vertex. When using this you simply keep track of the min/max of x/y/z over all vertices and get a bounding box for the surface.

Thanks for looking in!!!
Currently I am using Old version of the glu function which doesnt provide this facility.any other tricks!!!

Does it gives me Bounding Box of trimmed surface