okay thanks. So the key is that the bitcoin had to exist in a wallet, not merely exist. I thought a BCC could be claimed so long as the bitcoin existed (was mined already), so that bitcoins that were in "limbo" in some exchange could theoretically be withdrawn into a wallet to see if the corresponding BCC had been claimed already for that pre-existing bitcoin. It's too bad, given that BCC is $450 right now. :-(
Thanks!!
that is not correct. the existence of bitcoin is sufficient and there is no difference between existence in a wallet or exchange. the problem is, to access the BCC you need private keys for the address on which the bitcoins were during the event. when you buy on btc on an exchange, you dont get the private keys, you can withdraw to your address from which you have keys but the exchange will send you only BTC, so you cant access any BCC