[CMake] Supressing Make, but not Generators

[Eric Noulard]

2010/3/3 Smith Jack (Ext. - UGIS - UniCredit Group)
<jack.smith.extern at unicreditgroup.de>:
>
>
>> -----Original Message-----
>> From: cmake-bounces at cmake.org
>> [mailto:cmake-bounces at cmake.org] On Behalf Of J Decker
>> Sent: Wednesday, March 03, 2010 9:34 AM
>> To: cmake at cmake.org
>> Subject: Re: [CMake] Supressing Make, but not Generators
>>
>> You can test for platform flags..
>>
>> if( win32 )
>> add_subdirectory( these_compile )
>> #...
>> endif( win32 )
>>
>> ....
>>
>> or add specific options that can be checked
>>
>> http://www.cmake.org/Wiki/CMake_Useful_Variables
>
> Thanks , but that doesn't solve the problem.  If I conditionally include a sub directory, then the generator will not be run against the project in that subdirectory.
>
> I want to generator (VisualStudio/Eclipse/whatever) to always run so that I may always see the entire project hierarchy within my development environment, but the generated makefile to perform a platform test to see if it should build the target.
>
> Is this possible.

I don't think it is possible.

You want to export usual "CMake-time" decision to "Build-time",
the specific platform check are not meant to be exported at build time.

I'm not even sure it would be wise to try to do it (in the general case)
because with add_custom_command/target you may be trying to execute
platform specific executable on the wrong platform.

I think the "EXCLUDE_FROM_ALL" proposed by Hendrik and explained
by Michael is the best way to go.

What to compile will NOT be decided at Build time but you'll be able
to browse the code.

The CMake design is something like "one build tree for one platform"
what you ask for is more like "dynamic build tree for several platform".

As a side note I did cross some time ago a build system based on
hand-written re-entrant GNU makefile which supported the scheme you described.
I was nice but not that easy to maintain compared to a CMake build system.

All of this is off course my own point of view :-)

-- 
Erk
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