I'm not getting a correct wrapper for PetscDataTypeGetSize. #define PetscToPointer(a) (*(long *)(a)) void PETSC_STDCALL petscdatatypegetsize_(PetscDataType *ptype,size_t *size, int *__ierr ){ *__ierr = PetscDataTypeGetSize(*ptype, (size_t* )PetscToPointer((size) )); } Note that size is being dereferenced but should not be. This causes sys/examples/tutorials/ex5f90 to be broken. Jed