FindBoost.cmake (Was: kdesupport-for-4.2 cmake error)

[Pau Garcia i Quiles]

On Sun, Jan 18, 2009 at 11:28 AM, Andreas Pakulat <apaku at gmx.de> wrote:
> On 18.01.09 02:22:30, Pau Garcia i Quiles wrote:
>> On Sun, Jan 18, 2009 at 2:09 AM, Allen Winter <winter at kde.org> wrote:
>> > On Saturday 17 January 2009 7:51:44 pm Pau Garcia i Quiles wrote:
>> >> Hello,
>> >>
>> >> FindBoost.cmake in that version of kdesupport and in CMake 2.6.2 does
>> >> not support Boost 1.37.0. You need to replace this line:
>> >>
>> >> SET( _boost_TEST_VERSIONS ${Boost_ADDITIONAL_VERSIONS} "1.36.1"
>> >> "1.36.0" "1.35.1" "1.35.0" "1.35" "1.34.1" "1.34.0" "1.34" "1.33.1"
>> >> "1.33.0" "1.33" )
>> >>
>> >> with
>> >>
>> >> SET( _boost_TEST_VERSIONS ${Boost_ADDITIONAL_VERSIONS} "1.37.0"
>> >> "1.36.1" "1.36.0" "1.35.1" "1.35.0" "1.35" "1.34.1" "1.34.0" "1.34"
>> >> "1.33.1" "1.33.0" "1.33" )
>> >>
>> > This is quite silly.
>>
>> I fully agree but that's the way FindBoost.cmake is implemented in
>> CMake and several places in the KDE repository.
>>
>> Parsing boost/version.hpp seems like the right way to do version
>> detection. From Boost 1.35.0 :
>
> But how do you find that _easily_? Boost installs its headers into
> <prefix>/include/boost-<version>/boost/, so we need the version to try to find
> boost. The only way to avoid that is writing platform specific cmake code
> that iterates for <includedir>/boost-* and checks in each one for a
> boost/version.hpp.

FILE(GLOB ... ) and FILE( GLOB_RECURSE )...  to the rescue! Using the
globbing expressions "boost", "boost-*" and "Boost-*" would be
probably enough. Furthermore, you usually only have one version of
Boost installed, two or three tops, so FILE( GLOB/GLOB_RECURSE ...)
should not take long.

> This would be quite a bit more code, as <includedir> is
> different on each of the 3 major platforms.

FindBoost.cmake is already long enough (638 lines in CMake 2.6.2), so
a hundred more lines are not a problem, IMHO.

> IMNSHO we should either get Boost people to stop this insanity

Good luck with that! On the other hand, this "insanity" allows for
different Boost versions to be co-installed.

> or just
> better document that projects using FindBoost should set
> Boost_ADDITIONAL_VERSIONS to a list of versions they know their project
> builds with.

The problem with that is when a new version is out.

-- 
Pau Garcia i Quiles
http://www.elpauer.org
(Due to my workload, I may need 10 days to answer)