Will red cross tell you if your donated blood is positive for hiv?

Yes. In the first place, they wouldn't draw your blood if it is + , they screen all donors and make sure it is free of infection!
Yes. "Donors who are confirmed positive for any infectious disease are notified and have the opportunity to receive counseling with a specially trained, professional Red Cross donor counselor. " REF: http://www.redcrossblood.org/donating-blood/donation-faqs.