[CMake] What does `cross-platform' mean?

[Eric Noulard]

2008/11/7 Jed Brown <jed at 59a2.org>:
>>
>> If the underlying tool is efficient then CMake FIND module should find
>> the appropriate version.
>
> Thank you Eric, this greatly clarifies some design decisions.  May I
> interpret this to mean that CMake does not intend to be concerned with
> finding the `right' version of a library,

[...]

ok let's go on with this discussion.

> Unfortunately not every environment with multiple versions has the
> `module' tool and users will expect to be able to have a reasonable way
> to find specific versions of software.

I do perfectly understand your point I do remember similar problem
when I had a patchwork of versions (compiler, lib etc...)

> My development box has 4 MPI
> implementations and 4-16 (ABI-incompatible) versions of many libraries.

Nice environment indeed :=)

[...]
> It's much clearer if CMake never intends to support this usage.

I think this was not designed for that, just as CMake 2.4 was not
designed for cross-compiling.
The need came-in again and again and CMake developpers did
a good job to make it possible in CMake 2.6.

So not initially designed for it does not meant it won't ever
be supported.

>  With the `module' tool, I would load the appropriate modules, run cmake without any
> parameters, and (if the `module'-modules were set up with appropriate
> discipline) get a working build.  I agree that this is nicer for
> everyone (provided `module' is available),

My point of view, using the right tool for the right task and avoid
tool features bloat.

So should we/you put development effort to port/design
a portable "module tool" or should the needed constrained be
included in CMake?

I think I did have a look for a  "CRAY module" tool port for linux in the
past and I did find something but I cannot put the hand on it right now.

> but perhaps the CMake
> documentation could be explicit that you need to do something external
> to ensure that `incorrect' versions of libraries cannot be found by the system.

I think you cannot document something which has not been _widely_
encountered.

-- 
Erk