[CMake] Compaq Visual Fortran

[Brad King]

Arjen Markus wrote:
> the program is compiled and linked without a problem. But
> it writes:
> INFO:compiler[]
> INFO:platform[Windows]
> 
> I have examined the preprocessed source code and re-read the
> online documentation: all the macros defined in the table I
> looked at are available to the preprocessor, except, indeed
> _DF_VERSION_ and _VF_VERSION_.

In the Compaq Visual Fortran Programmer's Guide (cvf_pg.pdf) I see:

"The following preprocessor symbols are predefined by the compiler system
 and are available to compiler directives and FPP (except _DF_VERSION_):
 _DF_VERSION_= 650 (650 for Version 6.5; compiler only) ..."

Perhaps this means that _DF_VERSION_ is available only as a Fortran
language symbol.

So we conclude that the compiler provides no way to identify itself
using the preprocessor.  This will need non-trivial work in CMake to
recognize it.  We'll have to start running unrecognized compilers
with various "-V", "--version", etc. arguments hoping to find one
that prints the compiler name.

What is the output of

  f90 -what

?

-Brad