YCM build failing on Windows

[GiulioRomualdi]

I'm trying to compile the robotology-superbuild on Windows 10 with Visual Studio 2017
The process failed when YCM is built.
We noticed:

1. YCM builds directly in the folder build\robotology\YCM without throwing errors.
2. When YCM is compiled by the superbuild (i.e. running cmake --build . --config Release in build\) the process failed with the following error:

   2>------ Build started: Project: YCM (ExternalProjectTargets\YCM\YCM), Configuration: RelWithDebInfo x64 ------
   2>Creating directories for 'YCM'
   2>Building Custom Rule C:/Users/icub/sb/CMakeLists.txt
   2>CMake does not need to re-run because C:/Users/icub/sb/build/CMakeFiles/generate.stamp is up-to-date.
   2>Performing download step (git clone) for 'YCM'
   2>-- Avoiding repeated git clone, repository already exists
   2>Skipping update step for 'YCM'
   2>No patch step for 'YCM'
   2>Performing configure step for 'YCM'
   2>Not searching for unused variables given on the command line.
   2>loading initial cache file C:/Users/icub/sb/build/robotology/YCM/CMakeFiles/YCMTmp/YCM-cache-RelWithDebInfo.cmake
   2>CMake Error : error : generator : Visual Studio 15 2017 Win64
   2>Does not match the generator used previously: Visual Studio 15 2017
   2>Either remove the CMakeCache.txt file and CMakeFiles directory or choose a different binary directory.
   2>Done building project "YCM.vcxproj" -- FAILED.
   

We tried to change the branch of YCM from v0.10.4 (the default one of the superbuild) to master but nothing changed

@kouroshD @traversaro

[GiulioRomualdi]

We noticed that the by default YCM compiles in Win32 and it is not possible to switch from Win32 to x64

[traversaro]

I think this is related to #265 . Can you try to change the if in https://github.com/robotology/robotology-superbuild/blob/master/CMakeLists.txt#L116 to also cover MSVC/Windows, and try again on a clean build? Thanks!

[traversaro]

Otherwise build externally YCM is another workaround.

[GiulioRomualdi]

I think this is related to #265 . Can you try to change the if in https://github.com/robotology/robotology-superbuild/blob/master/CMakeLists.txt#L116 to also cover MSVC/Windows, and try again on a clean build? Thanks!

This one fixes the problem, should I open a PR?

[traversaro]

Yes, thanks!

I think this is related to #265 . Can you try to change the if in https://github.com/robotology/robotology-superbuild/blob/master/CMakeLists.txt#L116 to also cover MSVC/Windows, and try again on a clean build? Thanks!

This one fixes the problem, should I open a PR?

Yes, thanks. I avoided to just change the TAG as that is still an experimental commit, when the PR robotology/ycm-cmake-modules#294 , we will switch the tag for everyone.

[traversaro]

@GiulioRomualdi @kouroshD can you provide the code that is working for you? Thanks!

[traversaro]

Fixed by #295 .