setting up cmake builddirs

[Alexander Neundorf]

On Monday 12 November 2007, Andreas Pakulat wrote:
> On 12.11.07 20:58:45, Aleix wrote:
...
> > BTW, making the cmake support multiplatform (I am thinking about Windows
> > and MacOS X) would mean some new features that we don't have available
> > for now. For example, register features (Windows),
>
> Huh? I think I don't understand. What has cmake support to do with the
> registry (I'm assuming that was a typo, or was it not?)

You can read registry values in cmake under windows and use them e.g. as paths 
used in the find_xxx() commands. find_package() also checks the registry.

> > usage of ; to separe paths in $PATH (Windows),
>
> Uhm, do you read PATH somewhere?

Yes, e.g. find_program() uses it, and there are more env. vars supported by 
cmake, and these env. vars have the platform specific separators.

> > or Frameworks (Macos).
>
> I'm not that familiar with MacOSX frameworks, but this would only affect
> the gui right? (and of course the generation of cmake commands, which

It affects the result of find_library(), maybe also of find_path/find_file 
(for headers, I'd need to check). Since the result from find_library() 
probably affects the include directories, it affects e.g. code completion.

Actually since any result can be used in arbitrary ways, every result can 
affect everything:

if(some_lib_is_a_framework)
   include_directories(foo bar)
   add_executable(...)
   add_subdirectory(...)
   ...
else(some_lib_is_a_framework)
   ... do something else
endif(some_lib_is_a_framework)

> some flag to those)
>
> > Also, I am thinking that in the project configuration, instead of
> > choosing what modules directory to use, we should ask the binary to use
> > and extrapolate from there
>
> I'm not sure this works reliably, especially on Linux (I think MacOs,

Yes, it works, that's how cmake itself finds its module directory.

> but definetly Windows are less problematic here), where distro's like to
> put data files into various different places that you can't easily
> guess. And cmake doesn't provide a way to find that out - AFAIK. We

message(STATUS "${CMAKE_ROOT}")

Alex