[CMake] MSYS2 broken CMAKE_PREFIX_PATH

[Mario Emmenlauer]

Dear Alan,

thanks for your reply! Below more:

On 11.02.2018 23:11, Alan W. Irwin wrote:
> On 2018-02-11 15:13+0100 Mario Emmenlauer wrote:
> 
>>
>> I use mingw-w64-x86_64-cmake 3.10.2 on MSYS2. Generally it works well,
>> but just recently I started to have problems with CMAKE_PREFIX_PATH.
>> Its possible that the problems have been there forever, but I now just
>> found them due to a better use of CI systems.
>>
>> The problem is that cmake is not finding package configuration files
>> correctly. I have such files in DESTDIR/lib/cmake, i.e. for a library
>> XXX there are typically files XXXConfig.cmake, XXXConfigVersion.cmake
>> and XXXTargets.cmake (i.e. for Qt, VTK and others).
>>
>> But they are not found when I specify CMAKE_PREFIX_PATH=DESTDIR/lib/cmake
>> in Unix path style. It does work when I specify the package configuration
>> directory in Windows style! This makes things quite confusing, because many
>> find_xxx() commands for headers and libraries work with Unix paths. So now
>> I need to use CMAKE_PREFIX_PATH=UNIXDESTDIR for the normal find_xxx(), but
>> add WINDESTDIR\lib\cmake for the package configuration files (*).
>>
>> Is this an MSYS2 issue or a standard cmake issue? I reported it with MSYS2
>> here https://github.com/Alexpux/MINGW-packages/issues/3337 in case someone
>> can comment?
> 
> Hi Mario:
> 
> From <https://github.com/msys2/msys2/wiki/MSYS2-introduction>, and
> what you said above it appears you are using the "native Windows"
> cmake version from the mingw64 repository rather than the POSIX-style
> cmake package you can install from the msys2 repository.  I am pretty

Hmm, I don't think I have a native Windows cmake installed. I installed
mingw-w64-*-cmake from pacman, and I do not find any other cmake.exe in
PATH or on the hard disk. At least when I do:

#> find /c/ /d/ -name cmake.exe 2>/dev/zero
/d/msys2/bda/mingw32/bin/cmake.exe
/d/msys2/bda/mingw64/bin/cmake.exe

I find only the native MSYS2 mingw-w64-x86_64-cmake / mingw-w64-xi686-cmake.

All the best,

   Mario



> sure the native version would not do well with non-native POSIX-style
> paths so I am not surprised by your results.  Anyhow, I suggest you
> experiment with native versus POSIX cmake packages in both CMD and
> bash (from msys2) environments to establish what the different results
> are in those four cases for native Windows and POSIX paths.
> 
> Note I have no access to MinGW-w64/MSYS2 myself, but I do pay close
> attention to this platform because it is the best Windows platform for
> PLplot according to a fellow PLplot developer who does have a lot of
> practical experience with this platform.
> 
> Alan
> __________________________
> Alan W. Irwin
> 
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
> 
> Programming affiliations with the FreeEOS equation-of-state
> implementation for stellar interiors (freeeos.sf.net); the Time
> Ephemerides project (timeephem.sf.net); PLplot scientific plotting
> software package (plplot.sf.net); the libLASi project
> (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
> and the Linux Brochure Project (lbproject.sf.net).
> __________________________
> 
> Linux-powered Science
> __________________________
> 



Viele Gruesse,

    Mario Emmenlauer


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