Bill, Do you think it would be possible to enhance bfort to generate Fortran 90 interface definitions? Something like PetscErrorCode MatFactorInfoInitialize(MatFactorInfo info) becomes interface subroutine MatFactorInfoInitialize(info,ierr) MatFactorInfo :: info(11) PetscErrorCode :: ierr end subroutine end interface I think this would help with Fortran programmers writing correct codes much quicker. Thanks, Barry