[mpich-discuss] Warning: size of symbol `mpifcmb1_' changed from 40 in libfm_r32.a(fmm_full.o) to 20 in libmpich.a(setbot.o)

[Dave Goodell]

On Nov 10, 2011, at 4:21 PM CST, Jeff Hammond wrote:

> I'm confused by these errors:
> 
> /usr/lib64/gcc/x86_64-suse-linux/4.5/../../../../x86_64-suse-linux/bin/ld:
> Warning: size of symbol `mpifcmb1_' changed from 40 in
> libfm_r32.a(fmm_full.o) to 20 in
> /software/mpich/mpich2-trunk/install/lib/libmpich.a(setbot.o)
[snip]

IIRC this is MPICH2's fortran common block that implements special constants like MPI_BOTTOM.  If it changed size then something bad is almost certain to happen.

> mpif90 -c -cpp -O0 -fdefault-integer-8 -ffixed-form -fno-range-check fmm_full.f
> 
> I built MPICH2 like this:
> 
> ../configure CC=gcc F77=gfortran FC=gfortran CXX=g++ --enable-f77
> --enable-fc --enable-cxx --enable-g=dbg --with-thread-package=posix
> --with-pm=hydra --enable-threads --enable-debuginfo --enable-mpe
> --enable-romio --prefix=/software/mpich/mpich2-trunk/install
> 
> Is the problem that I did not build MPICH2 with FFLAGS=-fdefault-integer-8?

That is very likely, especially since it doubled in size.  You need to build MPICH2 with the same option (or get rid of -fdefault-integer-8 in your app).

-Dave