[CMake] IBM Fortran and the C Preprocessor

[Bill Hoffman]

Will Dicharry wrote:

> We do this because we need a quick way to choose our compiler (cmake
> chooses GNU on this system by default, and we have to use an MPI wrapper 
> compiler) and because we want those particular Fortran flags when the 
> MPI wrapper compiler is being used.
> When I use this toolchain file, the Fortran compiler ID is unknown (I 
> failed to see this before, the C and CXX compiler IDs were correct).
> 
> However if I comment out the set CMAKE_Fortran_FLAGS line or if I skip
> the toolchain file altogether and just pass
> -DCMAKE_Fortran_COMPILER=mpxlf90 into the cmake command, the compiler ID
> is VisualAge and everything works fine.
> 
> Am I misusing the toolchain file capability?
> 
Yes, that should only be used for cross-compiling.

To set the compilers you can set the environment variables FC, CC, and 
CXX before running CMake.

-Bill