Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5

[QMatthias]

Hello Qt community,

Success! With the new "qalgorithms.h" the x86 build works great again.
For your information:
[https://codereview.qt-project.org/#/c/236948/2/src/corelib/tools/qalgorithms.h](link url)

Special thanks to @SGaist !

Problem solved!

Many greetings from Germany,
Matthias

[sivabudh]

I too just upgraded to version 15.8.0 yesterday running Qt 5.10.1 on Windows x86 (32-bit) and ran into the same problem. My solution was to downgrade to 15.7.6.

[Doctor G]

@QMatthias

I replace the qalgorithms.h cleaned the cmake cache, did a full rebuild. And now it is working for me also.

I am using VS2017 15.9.4 and doing a x64 build with release symbols.

[Taytoo]

I'm getting this error on 5.12.0 static x86 build in Visual Studio 2017. Is the fix same?

[Christian Ehrlicher]

@Taytoo said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

Is the fix same?

If you use 15.8 then yes - it makes no different if you build Qt static or not here.

[Taytoo]

@Christian-Ehrlicher I have Visual Studio 2017 15.9.6 and Qt 5.12.0. Just tried the fix and its Not working.

[Christian Ehrlicher]

@Taytoo said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

Just tried the fix and its Not working.

Which fix?

[Taytoo]

@Doctor-G said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

@QMatthias

I replace the qalgorithms.h cleaned the cmake cache, did a full rebuild. And now it is working for me also.

I am using VS2017 15.9.4 and doing a x64 build with release symbols.

@Christian-Ehrlicher said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

@Taytoo said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

Just tried the fix and its Not working.

Which fix?

The one above

[Christian Ehrlicher]

Then I would say - update to 5.9.7 and make sure no old Qt version is around and try again since it's fixed in 5.9.7

[Taytoo]

@Christian-Ehrlicher you mean downgrade Qt from 5.12.0 to 5.9.7 - that's quite an old version. I need the high-dpi support in Qt.

Can anyone look into this issue, I'm sure I'm not the only one on 5.12.0 branch using VS2017?

[Christian Ehrlicher]

You're using 5.12? Then the fix is in there already... the problem here was only due to problems with Qt5.9.5/.6 and VS 2017...
Do you compile Qt on your own?

[Taytoo]

@Christian-Ehrlicher said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

You're using 5.12? Then the fix is in there already... the problem here was only due to problems with Qt5.9.5/.6 and VS 2017...
Do you compile Qt on your own?

Yes and Yes

[Taytoo]

Fixed preprocessor error by updating header file:

#if defined(__cplusplus)
#if defined(__clang__)
#if QT_HAS_CPP_ATTRIBUTE(clang::fallthrough)
#    define Q_FALLTHROUGH() [[clang::fallthrough]]
#endif
#elif defined(__GNUC__)
#if QT_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
#    define Q_FALLTHROUGH() [[gnu::fallthrough]]
#endif
#elif QT_HAS_CPP_ATTRIBUTE(fallthrough)
#  define Q_FALLTHROUGH() [[fallthrough]]
#endif
#endif

[aha_1980]

@Taytoo May I ask which header file you changed, and what exactly? Thanks!

[Taytoo]

@aha_1980 The change was in qcompilerdetection.h Line: 1349.

Weird thing is that now that I've fixed the linker issue I was experiencing, compiler is Not complaining of the code - I've reverted qcompilerdetection.h back to its original version. Even though, looking at the file in VS the offending lines are still marked red, I guess moc is taking care of it somehow.

[Langston]

Hello,
I am using QT5.13.1+VS2017 and I have encountered this kind of error. I am very surprised that the latest version will have such a problem.

[Christian Ehrlicher]

@langston said in Problem with new Visual Studio update 2017 Version 15.8.0 and Qt 5.9.5:

I am very surprised that the latest version will have such a problem.

Did you compile Qt by yourself? I've no problems with MSVC 2017 + Qt5.12/5.13 so make sure you don't use an older compiler or something similar.

[Langston]

@christian-ehrlicher
Hello, first of all, I am very grateful for your reply.
No, I am downloading the qt version from the official.
Here is the download address: http://download.qt.io/official_releases/qt/5.13/5.13.1/
I chose qt-opensource-windows-x86-5.13.1.exe

[Christian Ehrlicher]

And which exact MSVC2017 version do you use? Please update to at least 15.9.8 ( see https://docs.microsoft.com/de-de/visualstudio/releasenotes/vs2017-relnotes )

[Langston]

@christian-ehrlicher
thank you for your reply.
I am using MSVC 2017 Enterprise Edition 15.9.16.
And Is this a problem with this version?