[Development] Qt Coding style and C++11

[André Hartmann]

Hi Kevin,

Am 15.11.2017 um 17:39 schrieb Kevin Funk:
> On Monday, 18 September 2017 10:03:40 CET Kevin Funk wrote:
>> On Monday, 18 September 2017 09:38:53 CEST Ville Voutilainen wrote:
>>> On 18 September 2017 at 10:36, Lars Knoll <lars.knoll at qt.io> wrote:
>>>>>> But for new plugins that target a known platform that supports c++11,
>>>>>> they can most likely use new conventions. Unless someone can come up
>>>>>> with technical reasons the new c++11 member initialization is better
>>>>>> than what is there now, I’d rather keep it the same as it is now.>>
>>>>>
>>>>> If you have more than one constructor that set a member to the same
>>>>> value, it's arguably simpler and less error-prone
>>>>> to use a member initializer.
>>>>
>>>> I also think that we should be using member initialisers when writing
>>>> new
>>>> code (or when refactoring existing code). But doing a global
>>>> search/replace of existing code might lead to subtle errors as it's easy
>>>> to miss the rare case when different constructors initialise members
>>>> differently.
>>>
>>> Note that if you have both a member initializer and a ctor-initializer
>>> (the colon-list after the constructor signature, X() : foo(a),
>>> bar(b)), the ctor-initializer
>>> is used. It is non-trivial to remove ctor-initializers and replace
>>> them with member-initializers, I don't know whether the clang-tools
>>> can do that.
>>
>> I have to take back my claim that clang-tidy can automatically transform
>> initialization via initializer list to initialization via in-class field
>> initializers.
>>
>> I just remembered that this cppcoreguidelines-pro-type-member-init checker
>> just *adds* in-class field initializers for fields which haven't been
>> initialized altogether *before*. It does nothing if the initializer list
>> initializes all fields already. So in order to actually port all uses of
>> initializer lists to something more modern, clang-tidy would need to be
>> extended.
>>
>> So I guess the discussion whether to a global search/replace for this
>> particular C++11 feature is moot for now, since doing this port on all of Qt
>> is infeasible without proper tooling.
> 
> Heya,
> 
> And I have to revive this thread again.
> 
> Actually the clang-tidy check to do this kind of transformation indeed exists
> already (since Clang 5.0 release):
>    https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-default-member-init.html

Thanks for the hint.

That reminds me, that the wiki page [1] for C++11 stil states:

   "Note: This section is not an accepted convention yet.
   This section serves as baseline for further discussions."

Regards,
André

[1] https://wiki.qt.io/Coding_Conventions

> 
> Just for your information.
> 
> Regards,
> Kevin
>   
>> Regards,
>> Kevin
>>
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>>
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> 
> 
> 
> 
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-- 
Best regards / Mit freundlichen Grüßen
André Hartmann, Dipl.-Ing. (FH)
Software Project Manager

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