[mpich2-dev] CFLAGS ordering in mpicc

[Joe Ratterman]

One of the requirements of the layout change was that all code that used to
compile still compiles without changes.

   - Without the -I...., people who use other headers may get errors.
   - With the -I...., people who use those other headers in new locations
   may get errors.

What errors exactly could happen in mpif77?


Thanks,
Joe Ratterman
jratt at us.ibm.com


On Wed, Jun 25, 2008 at 12:05 PM, Anthony Chan <chan at mcs.anl.gov> wrote:

> Hi Joe,
>
> The problem here is that you used CFLAGS to set dcmf/spi include directory
> when configuring
> MPICH2.  mpicc and friends generated by configure has this line during
> linking/compiling( as you've pointed out)
>
> $Show $CC $CFLAGS $allargs -I$includedir
>
> user's include path will be in $allargs.  This causes a problem because
> dcmf/spi
> is in CFLAGS before user's.  Swapping $CFLAGS and $allargs in mpicc.in and
> friends
> could solve the problem, but then it may cause portability issue for MPICH2
> on other
> platforms(especially with mpif77/mpif90....).   I wonder if you could use
> MPICH2LIB_CFLAGS
> and friends to point to dcmf/spi headers when configuring MPICH2 with
> dcmfd.  That way mpicc and friends won't have
> -I/bgsys/drivers/ppcfloor/comm/sys/include.  If users want to include
> dcmf/spi
> headers with mpicc and friends, they could include the headers explicitly.
>  Main thing here
> is that mpicc (mpixlc in your case) are for compiling MPI programs, so i
> would naively think
> you don't need -I/bgsys/drivers/ppcfloor/comm/sys/include unless your mpi.h
> contains references
> to dcmf/spi symbols....
>
> PS.  The user that you refered to could be me....
>
> A.Chan
>
> ----- "Joe Ratterman" <jratt at us.ibm.com> wrote:
>
> > We are looking at a problem reported by a user. We recently moved some
> > files around in our system. Previously, various communication include
> > files were located in the same dir as the MPI header files. This was
> > simple for the users, but for various reasons they have been moved
> > into another area, which we added to the WRAPPER_CFLAGS var via the
> > CFLAGS var at configure time.
> >
> > It seems that the user is having difficulty over-riding the built-in
> > helper directory. For example:
> >
> > mpicc -show -I/11111111111 -c foo.c -I/2222222222
> > cc -I/bgsys/drivers/ppcfloor/comm/sys/include -I/11111111111 -c foo.c
> > -I/2222222222 -I/bgsys/drivers/ppcfloor/comm/include
> > MPI Files : /bgsys/drivers/ppcfloor/comm/include
> > Other comm includes (that the user hopes to over-ride) :
> > /bgsys/drivers/ppcfloor/comm/sys/include
> >
> > The following are the interesting lines in the mpicc file
> >
> > prefix=/bgsys/drivers/ppcfloor/comm
> > includedir=${prefix}/include
> > WRAPPER_CFLAGS="-I/bgsys/drivers/ppcfloor/comm/sys/include"
> > CFLAGS="$WRAPPER_CFLAGS"
> > $Show $CC $CFLAGS "${allargs[@]}" -I$includedir
> >
> > It doesn't really seem correct (in this case anyway) to have CFLAGS
> > ahead of the user args. Is there a specific reason that I am missing?
> > Is it something that should be changed?
> > MPICH2 Version 1.0.7
> >
> >
> > Thanks,
> > Joe Ratterman
> > jratt at us.ibm.com
>
>
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