[Development] QVector now has rvalue push_back

[Gunnar Roth]

Hello,
Out of curiosity i just looked at the Xcode 6.4 headers for the implementation of std::vector::emplace_back,
and i don’t think there is any difference between push_back(QPen(Qt::red,1.5f)) and emplace_back(Qt::red,1,5f))

The implementation is like this:
    template <class... _Args>
    _LIBCPP_INLINE_VISIBILITY void emplace_back(_Args&&... __args)
        { push_back ( value_type ( _VSTD::forward<_Args>(__args)... )); }


Am i wrong?

Regards,
Gunnar

> Am 21.07.2015 um 18:53 schrieb Thiago Macieira <thiago.macieira at intel.com>:
> 
> On Tuesday 21 July 2015 12:22:36 Matthew Woehlke wrote:
>>  std::vector<QPen> list;
>> 
>>  // less efficient
>>  auto&& pen = QPen{Qt::red, 1.5f};
>>  list.push_back(pen);
>> 
>>  // more efficient
>>  list.emplace_back(Qt::blue, 2.0f);
> 
> This is a lot clearer. Thanks!
> 
> -- 
> Thiago Macieira - thiago.macieira (AT) intel.com
>  Software Architect - Intel Open Source Technology Center
> 
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