Errors when building CMake and VTK

amaclean

I am using Qt Prebuilt MSVC-2015 64bit. The Qt version is 5.8.0-1. Building VTK and CMake with VS 2017.

This error occurs: 'error C3615: constexpr function QAlgorithmsPrivate::qt_builtin_ctz' cannot result in a constant expression

It seems the fix for this problem, see: http://lists.qt-project.org/pipermail/development/2016-December/028026.html
never made it into the release.

Any ideas when this will be fixed?

jsulm

@amaclean If you follow the link you will see that the patch is already merged in 5.8 branch: https://codereview.qt-project.org/#/c/177743/
But you can download the patch from the above link and apply it before building.

amaclean

Thanks for that, I can verify that the merge I referred to did make it into the release. So the problem is a different one.

Here is a possible fix:
The problem relates to the Qt macro:
Q_DECL_CONSTEXPR

If it is commented out in lines 593 to 714 of qalgorithms.h then the builds work for CMake and VTK and any other Qt build using VS2017.

Regards

jsulm

@amaclean Maybe you should file a bug report?

amaclean

@jsulm Thanks, already done.

SGaist

Hi,

Can you share the link please ? That will make it easier to find :)

amaclean

Here it is: https://bugreports.qt.io/browse/QTBUG-59575
It seems that the patch https://codereview.qt-project.org/#/c/177743/ never made it into the release.

SGaist

It went in but after the release of 5.8.0. So if you need it, either check the 5.9 alpha or build from Git.