[Qt-creator] Using C++11 in Creator's source

Poenitz Andre Andre.Poenitz at digia.com
Wed Mar 5 11:12:18 CET 2014

Ziller Eike wrote:
> On Mar 4, 2014, at 2:09 PM, Daniel Teske <daniel.teske at digia.com> wrote:
> > Hi,
> >
> > since we have branched 3.1 from master, master no longer needs to support OS X
> > 10.6. As such I propose, that we open up master for those C++11 features that
> > are supported by VS 2010, g++ 4.5 and clang 3.1.
> >
> > I think it's too early to require a newer version of Visual Studio, though
> > requiring those 3 compilers gives us both *auto* and *lambda*.
> >
> > I suspect that in practice the minimum g++ or clang version will be higher,
> > since practically no one uses those versions any more.
> >
> > We need to extend the coding rules for auto and lambda. Suggestions are
> > welcome for that.
> One rule for using “auto” that I’d like to establish, is to use it only “when the type is obvious when reading the code”.
> Of course what that exactly means should be discussed and shown in some examples, and then it’s still up for interpretation.
> E.g.:
> Yes:
> auto f = new FooBar;
> auto a = new A;
> auto myAction = menu->addAction(…);
> auto it = list.const_iterator();
> No:
> auto i = 4; // the difference between “4;” and “4.;” is subtile with big consequences

What is obvious for some might unfortunately not be so obvious for others.

>From the list of "Yes" cases I only fully agree with "auto it = list.const_iterator();"

I'd actually like to restrict the use of auto to cases where it "significantly" reduces
typing and line noise (say, identifiers longer than x chars, and to cases where 
it doesn't change meaning.

Simple types ('int', 'bool', 'double' ... should never be 'auto'd', and I am tempted to
include "simple Qt value types" like 'QString' in this section.

For the pointer cases, we should spend a thought or two on possibly requiring 
 auto *f = new FooBar;

to keep the visual clue that this is a pointer that might (or might not) need some 

It would be nice if <F2> on 'auto' would jump to the definition of the 'real' type.

I'd also like to get some time to collect experience with the new toys before
major existing hunks of code are converted.


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