Re: [jamboost] problem with parallelism feature example in documentation

From: Vladimir Prus (ghost_at_[hidden])
Date: 2004-11-29 06:19:03

On Monday 29 November 2004 12:17, Toon Knapen wrote:

> > lib libmpi
> >
> > : # sources
> >
> > mpiheaders
> >
> > : # requirements
> >
> > <file>/usr/local/mpich-1.2.5.2/lib/libmpich.a
> >
> > : # default-build
> > : # usage-requirements
> >
> > <use>/user-config//mpiheaders/<parallelism>none
> > ;
> >
> > Why "mpiheaders" are in sources? Does removing them help? If not, try
> > running
>
> This is some kind of trick. My fake-mpi library uses the exact same
> headers as the real mpi library (to have binary compatibility. This way
> I can link the same object files with either the fake or the real mpi
> library and thus only compile the object files one for later generating
> a parallel and sequential application).

This makes sense. I did not mean that this code is wrong, just was trying to 
figure out why it's there and if it, or something else, causes the problem.

> To make sure the fake and real use the same header files, I define the
> header-files once (using the mpiheaders target) and add this as a source
> (and thus also dependency) to the real mpi (libmpi) and my fake mpi
> library.
>
> Actually what I'm trying to do with this parallel feature is that I can
> compile my application first with the fake feature and than generate
> another exe linked to the real mpi that is linked to all the libraries
> that were already compiled for generating the sequential exe.

Oh, that's cool. The joy of dynamic linking ;-)

- Volodya