datastax/cpp-driver — pull request #19 by mhfrantz (2014-03-07 19:34:48+00:00)
Title: Change sense of return of cql_message_result::is_null to align with get_* methods

It seems that the bool returned by is_null ought to have the same sense as the bool returned by the various get_* methods. That is, a "true" should mean that the method completed correctly. This is how it was a while ago, so this PR restores the original API design.