As others have pointed out, it's up to the credit card company. This is quoted from our Amex Surpass:

We don't issue credits for pending charges because they don't increase your outstanding balance. Most pending charges are removed at the end of the day by posting a purchase to your account. This is what happens, for example, when a merchant that has submitted a pre-authorization submits the final charge amount. If a merchant submits a pre-authorization but doesn't submit a final charge amount within 8 days, we remove the pending charge without posting a purchase to your account.

If you are close to your credit limit on your card, you really have to be aware of what some merchants pre-authorize on your card. Gas stations seem to be the worse at pay-at-the-pump, as the places we buy gas, $100 is normal, however Kroger is $140.

On a motorcycle trip this past summer out west, a friend who was riding with us was using his Surpass card to get gas as he was building up points. We did not know he was so close to his limit, and the problem was when we stopped for gas, every place was pre-authorizing the pay-at-the-pump for $100. After 4-5 days, he hit his credit limit from the authorizations and was declined. We were averaging $15-18 at one gas stop each morning, far from the several hundreds that was being held against his credit line.

On the last trip, he took the card to the clerk and had them turn on the pump, then fill up & paid them the amount owed. It worked out for that trip as planned as there was no pre-authorizations.