Problem with Compaq F77 5.3 compiler and workaround

The Compaq f77 compiler generates peculiar F95 error messages when compiling files with the .F extension.

fir-mc0% cat x.F
        program test
        print *,'hello world'
        stop
        end
fir-mc0% f77 x.F
cpp: Severe: No such file or directory
... file is '`-DLANGUAGE_FORTRAN_95'
f90: Severe: The input stream is empty

The problem has shown up as the compiler has been upgraded on MMM platforms, including fir and most recently the classroom workstations.

The problem is related to the fact that Compaq now implements f77 with a link to the f90 compiler. Compaq has provided an option, -old_f77, to have the new improved f77 command actually behave like f77. Unfortunately, older versions of the compiler do not support -old_f77 and will generate an error if this is used. The problem will occur when make mpp attempts to compile RSL using the mpif77 command.

Here are a couple of possible works-around for MM5v3.3 :

If you are using the MPP version of MM5 and mpich (say, on the classroom workstations):

- Edit the file MPP/RSL/RSL/makefile.alpha change the definition of FC to read FC = f77 -old_f77

If you are using the MPP version of MPP and Compaq's MPI (say, on fir.mmm.ucar.edu)

- Edit the file MPP/RSL/RSL/makefile.alpha and change the definitoni of FC to FC = f90

Hopefully, this will be straightened out by the time MM5v3.4 is released.

-Rotang, June 30, 2000