[mpich-discuss] MPICH 2 installation errors

[chan at mcs.anl.gov]

> > configure: error: ****  Incompatible Fortran and C Object File
> Types!  ****
> > F77 Object File Type produced by "gfortran  -O2" is : : Mach-O
> object i386.
> >  C  Object File Type produced by "gcc  -O2" is : : Mach-O 64-bit
> object x86_64.
> 
> Yes, this message is a 32/64-bit compatibility issue.  Your fortran
> compiler is outputting 32-bit by default, but your C compiler is
> outputting 64-bit by default.  The GNU compilers (and many other
> compilers) accept "-m32" or "-m64" options to force the corresponding
> output mode.  The easiest way to set them is usually something like:
> 
> /path/to/configure CC="gcc -m32" F77="gfortran -m32" FC="gfortran
> -m32" OTHER_CONFIG_ARGS...

Since you are using MPICH2-1.2.x, you should use F90 (not FC) to
set Fortran 90+ compiler (FC in 1.2.x and older releases is the
same as F77), i.e.

/path/to/configure CC="gcc -m32" F77="gfortran -m32" F90="gfortran -m32" CXX="g++ -m32" OTHER_CONFIG_ARGS...

In the upcoming 1.3 release, F90/F90FLAGS are being
replaced by FC/FCFLAGS.  So the configure command will
be exactly like what Dave said.

A.Chan