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

Thiago Macieira thiago.macieira at intel.com
Tue Jan 14 16:21:15 CET 2020

On Tuesday, 14 January 2020 01:15:35 PST Olivier Goffart wrote:
> I know that.
> But since we are supposed to mandate C++17 in dev, what the other path[0]
> does is simply to discard this test altogether and add the -std=c++17
> anyway. That patch had a CI test run without macOs, and every platform
> passed. (although no C++17 is already in use, so maybe there are further
> issues)
> [0] https://codereview.qt-project.org/c/qt/qtbase/+/283832

You'll only find the issue on iOS/macOS on some earlier versions. Though I 
thought that we caused warnings that turned into error. I think the Darwin 
problem will be solved, as soon as the CI updates.

We also have the option of only requiring the C++17 core language, but only 
the C++14 standard library, at least for 6.0 and the first couple of releases. 
After all, C+17 is less than 3 years old now and there are plenty of compilers 
with implementation issues. We've never required something so new before.

> I'm afraid it will still take quite some time before this happen because,
> if i understand correctly, the patches have to reach each branches before
> going to the dev branches, then qt5.git has to integrate, which may happen
> to be quite difficult given the problem we have to synchronize all
> modules). Then hopefully there is no further problem.

I don't think there's a way out of this just yet.

I'll modify my patches to work with C++14.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel System Software Products

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