[cmake-developers] Installing Toolchain files (Was: Building with Qt for the Raspberry Pi with CMake)

Stephen Kelly steveire at gmail.com
Mon Apr 15 15:34:56 EDT 2013


Alexander Neundorf wrote:

> On Monday 15 April 2013, Stephen Kelly wrote:
>> Alexander Neundorf wrote:
>> > I think that's a good idea.
>> > Qt, once built, knows where the compiler is and what the target
>> > operating system is, so it is a good source of information for that.
>> > It also knows at least some part of CMAKE_FIND_ROOT_PATH, that would be
>> > its own install locations, maybe it knows even more about where things
>> > are to be found for the target ?
>> 
>> I've uploaded the change I've worked on for Qt:
>> 
>>  https://codereview.qt-project.org/#change,53858
>> 
>> The CMAKE_FIND_ROOT_PATH is indeed known, as is the CMAKE_PREFIX_PATH and
>> all relevant compilers. That seems to be all the relevant information for
>> a toolchain.
> 
> Mostly. CMAKE_FIND_ROOT_PATH can also contain additional user-specific
> directories, but I guess it's ok.
> It's actually great, since this should make cross-compiling with Qt much
> easier :-)

Yes, that's the plan :). If needed, one could wrap the Qt5Toolchain.cmake 
anyway I think.

>> When building Qt, a sysroot can be passed to the configure script, and a
>> so- called 'host-prefix' can be passed too. Cross compiled libraries get
>> installed into the prefix, and host-compiled tools like moc and qmake get
>> installed to the hostprefix. In my patch, I install the toolchain file to
>>
>>$$hostprefix/cmake/Qt5Toolchain.cmake
> 
> Is hostprefix somewhere in lib/ ?

No. It's specified when configuring Qt. See the paragraph above. 

Thanks,

Steve.





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