Nevermind - I answered my own question:
was trying to use:
DBBindColChar (SQLstmt, 2, 11, CalLast, &status, "");
which I assumed would work fine using the "default" formatting - but only returned ""
so I tried:
DBBindColChar (SQLstmt, 2, 11, CalLast, &status, "GD");
which did the same thing
so then tried
DBBindColChar (SQLstmt, 2, 11, CalLast, &status, "mm/dd/yyyy");
which works as intended.