puzzled by 'cc1: error: unrecognized command line option "-fdefault-real-8"'

[Steve Kargl]

On Sat, Oct 23, 2010 at 01:45:35PM -0500, Anthony Rollett wrote:
> Apologies if the solution to this is obvious but I have a macbook, with 10.6, up to date XCode, openmpi, gfortran (from http://r.research.att.com/tools/) installed.  Am trying to compile an mpi f90 program for which the options include -fdefault-real-8.  I get the error message in the subject line.  I tried using -r8 but I then get errors that suggest that real variables are being left as real*4, and not real*8.  If anyone can illuminate my ignorance I would be most grateful!
> Tony Rollett, Carnegie Mellon

-fdefault-real-8 is a gfortran only option.
The error message clearly indicates that you
tried to use with the C compiler.  Remove
it from CFLAGS.

-- 
Steve