How to run macro with parameters in batch mode?

I have a file myfile.C like this:

void myfile (Int_t a=5, Int_t b=1) { //something... }
I want to run it at root startup in a batch mode:

But:

root -b myfile.C (6,2) Badly placed ()'s.

What is wrong? How can I do that?

(Yes I can first do root -b and then .x myfile.C (6,2) but I want to run at startup).

see first/second page of the chapter "Getting Started"
ftp://root.cern.ch/root/doc/2GettingStarted.pdf

Rene

thanks
and sorry for such a stupid question.