[Haskell-cafe] compile error with FFI code

Hello, In my blah.hsc, I have "allocbytes (#const (struct bozo)) .. where struct bozo is a bunch of "long int" ,,, In the "runhaskell Setup.hs build" step I get a nasty error message about an "incomplete type". I have look at many times but this error doesn't make sense to me. ?? Kind regards, Vasili