[cmake-developers] CMake 2.8.11-rc3 ready for testing!

[Stephen Kelly]

Biddiscombe, John A. wrote:

> May I ask one question related to the "Target Usage Requirements" ...
> 
> For HDF5 (for example), the user might enable Parallel IO, which requires
> MPI. When enabled, the hdf5 cmakelists use find_package to get MPI and all
> is fine.

Hi there,

I am not familiar with hdf5 or mpi. 

What are you referring to when you say "the hdf5 cmakelists" ? Do you mean 
FindHDF5.cmake?

> 
> Users of hdf5 might not know that they are using an hdf which has parallel
> IO enabled, and compilation is complicated by the unexpected dependency on
> mpi libs and includes

Can you be specific about what is more complicated? I'm not familiar with 
what is complicated.

> Is this new feature designed to resolve this long standing irritation so
> that when installed, the hdf5 will add the mpi dependency behind the
> scenes? 

Sort of/maybe. It is designed for use with IMPORTED targets, which in 
general means that the upstream uses CMake and installs a Config.cmake file. 
As there is a FindHDF5.cmake, I'm guessing that is not the case here.

However, it would be possible to create IMPORTED targets in the Find file.

However, there may be other ways of solving the problems you're experiencing 
regarding convenience, even without these features. Using these features has 
certain conveniences, but they don't seem to be what you're after. What 
you're after seems to be possible anyway. PNG_LIBRARIES contains 
ZLIB_LIBRARY for example, because it depends on it. Should HDF5_LIBRARIES 
contain MPI_LIBRARIES?

Sorry I can't give more useful information. Maybe someone else can.

Thanks,

Steve.