[CMake] Cross-compilation vs FindQt4.cmake

[Alexander Neundorf]

On Saturday 05 June 2010, Andrey. wrote:
> 03.06.10, 16:19, "Alexander Neundorf" <a.neundorf-work at gmx.net>:
> >  > > This can be done by
> >  > > - setting CMAKE_PREFIX_PATH so that it points to the base directory
> >  > > where that qmake is installed
> >  > > - setting QT_QMAKE_EXECUTABLE directly when running cmake:
> >  > > cmake -DQT_QMAKE_EXECUTABLE=/your/qmake
> >  >
> >  > I've already mentioned, that I simply modify PATH variable as it works
> >  > both for qmake and other tools. I don't like touching
> >  > CMAKE_PREFIX_PATH, because then cmake will attempt to look for
> >  > libraries in "${CMAKE_PREFIX_PATH}/lib" and can pick up libraries,
> >  > compiled for host system. Also, I'm not sure, how well
> >  > CMAKE_PREFIX_PATH would work together with CMAKE_FIND_ROOT_PATH.
> >  >
> >  > > How far do you get with this ?
> >  >
> >  > 1) FindQt4 finds my qmake
> >  > 2) FindQt4 runs "qmake -query" or "qmake CMakeTmpQmake/tmp.pro"
> >  > 3) FindQt4 gets, i.e.
> >  > QT_INSTALL_LIBS:/I/configured/qmake/for/this/root/usr/lib/qt4 4)
> >  > Obtained QT_INSTALL_DIR is wrong, because it may point to host
> >  > libraries, required for moc, or somewhere else.
> >
> >  The directory reported for the libraries is also the wrong one, i.e. the
> > one for the qmake which is currently running, right ?
>
> Right.
>
> >  Does the target Qt also have a qmake, moc and uic ?
>
> No, there is no need for them.
> They aren't supposed to be run on target machine.
> Also, there is no reason of running them on host either.
>
> But again, other cross-environments may have them.
>
> >  Is there any relation (installation location-wise) between the moc and
> > uic (and qmake) which have to be used and the location of the target Qt
> > installation, i.e. the lib and include dirs ?
>
> In general, no.
> Any such relation is either quite cross-environment specific or
> non-existent. For example,
> 1) moc and uic are located at /home/me/cross-devel/tools/bin
> 2) target lib dir is
> /home/me/cross-devel/build/my_internal_target_name/usr/lib
>
> That is why, I do like the idea of using pkg-config:
> 1) .pc files are usually placed near libraries (${libexecdir}/pkgconfig)
> 2) It's easy to tell pkg-config the sysroot dir

Can you please put all that in the cmake bug tracker 
(http://public.kitware.com/Bug) so all that information doesn't get lost ?

Thanks
Alex