[Development] Are we already allowed to use C++17 in dev?

[Olivier Goffart]

On 08.01.20 18:21, Thiago Macieira wrote:
> qcc doesn't seem to support it.
> 
>   kernel/qcoreapplication.cpp: In static member function 'static void
> QCoreApplicationPrivate::initLocale()':
>   kernel/qcoreapplication.cpp:601:45: error: expected ')' before ';' token
>            if (int dot = newLocale.indexOf('.'); dot != -1)
>                                                ^
> 
> https://testresults.qt.io/logs/qt/qtbase/
> e1d8826ce4d4cc6aa21478373b55ad23e0376e33/
> LinuxRHEL_7_6x86_64QNXQNX_700armv7GCCqtci-linux-RHEL-7.6-
> x86_64-4b56bfDisableTests/d4c1bf09ea5df0129c22c51a6f079bdfb1b58333/
> build_1578500712/log.txt.gz
> 
> If yes, please turn that compiler off.


Not yet:

- qmake isn't build with -std=c++17 yet, so you can't have C++17 in the files 
used by the boostrap lib. (.cpp or .h)
- examples and tests are not yet build with C++17 by default
- We still build for MacOS 10.13 which do not support the C++17 stdlib

All of this would be fixed by 
https://codereview.qt-project.org/c/qt/qtbase/+/283832

But the CI would still fail because it still runs with MacOS 10.13
and we don't want running the test with MacOS 10.13 just yet because tests are 
not run on MacOS 10.14 because they are failling:

https://codereview.qt-project.org/c/qt/qt5/+/284310

https://bugreports.qt.io/browse/QTQAINFRA-3108
https://bugreports.qt.io/browse/QTBUG-75786

IMHO, these two issues should be P0 because if we are serious about using C++17 
fir Qt6, we should be able to do it now. This has been a blocker for months. If 
some tests are can't be fixed on MacOs 10.14, they should then be blacklisted 
so we can still proceed with C++17.

And this issue you have in 
"LinuxRHEL_7_6x86_64QNXQNX_700armv7GCCqtci-linux-RHEL-7.6", is maybe something 
else. (Maybe https://codereview.qt-project.org/c/qt/qtbase/+/283832 fixes it, 
maybe not)

-- 
Olivier