integration limit {-infinity, infinity}...

Dear ROOT Experts,

Just lately I have posted a mail regarding integration limit {-infinity, infity} but I still did not have a clear idea. For example, a Normalized Gaussian Function when integrated from -infinity to infinity is known.

These are my questions:

1. Is the integration limit {-infinity, infinity} implemented in ROOT?
2. How is it wriiten in the program?
3. If not implemented, is there a kind of "RULE of THUMB" or TRICK thing so that integration limit {-infinity, infinity} can still be applied? (I mean using a very very large number can be used to mean infinite, I think)

Thanks.

-- 
Zaldy A. Nawang