[Releasing] Non C++11 compilers

Thiago Macieira thiago.macieira at intel.com
Tue Jun 30 23:09:07 CEST 2015

On Tuesday 30 June 2015 22:57:32 Jason H wrote:
> I was perusing the archive of this list so I would know what to expect
> tomorrow and saw that there was a suggestion to drop non C++11 compilers.

Hello Jason

Your discussion is better held in the developer mailing list. I'm Cc'ing it. 
Please drop the releasing mailing list when replying.

> As a former embedded developer, I have to be concerned about that. A number
> of legacy software projects in the embedded space have ancient compilers in
> the BSP (board support packages). The project I was formerly a part of had
> code from 1992, released in 1994 on a 68000, and had been ported through
> the years to various AMX-ish RTOSes. The code base is still alive and well,
> having been ported to a PPC 832e and now later PPC chip. I had been working
> on modernizing the code base to eventually port the GUI to Qt. This project
> has seen exactly 2 changes to the compilers in the 20 years it's been on
> the market. Both Metrowerks (Now Freescale).

Do they use Qt 5.4 right now? When are they considering upgrading to Qt 5.7?

> While it may not be 'cool' or 'hip' I'd caution against the dropping of non
> C++11 compilers. These legacy systems are still out there. I don't know how
> anecdotal my experience is of other projects, but it was a $8B USD company.
> I know these systems aren't that sexy when a TI ARM7 has a GPU on it, and
> can be had for dollars, but I think plenty are out there.

That boat has sailed. We will adopt C++11 in 2016.

> Meanwhile.... I've never used any C++11 feature, or typed any line of C++11
> code. I personally am against the idea of C++11, as it fractures the code
> base of C++ into C++98 and C++11. I use Qt because it compiles everywhere
> and gets me past the limitations of C++98 in an easy way. I won't be able
> to do that if Qt drops C++98 support.
> So in summary, I think dropping C++98-only compilers will significantly
> detract from Qt features in unanticipated ways.

We've considered all of that. We don't agree with your assessment.

Of the compilers we support right now, only MSVC 2008 and 2010 have limited 
C++11 support. We'll also drop a few releases of GCC, all of them more than 5 
years old by the time of the Qt 5.7 release. So we're talking about dropping 
those compilers only, after an LTS release.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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