[Development] QVector now has rvalue push_back (was: Re: HEADS UP: potential trouble from a recent QVector change)

[Marc Mutz]

On Tuesday 21 July 2015 11:23:26 Allan Sandfeld Jensen wrote:
> On Monday 20 July 2015, Marc Mutz wrote:
> > https://codereview.qt-project.org/121810
> > 
> > So start using qMove() or pass temporaries in your QVector::append()
> > calls.
> 
> Are we also using move internally when resizing and detaching?

No.

For detach, we cannot (we need a copy).

For resize, the pressure to implement it isn't very big, because most types 
that have a move ctor can also be Q_MOVABLE_TYPE (or, soon, 
Q_RELOCATABLE_TYPE, ie. Q_MOVABLE_TYPE, except for QList), and just realloc() 
is still faster calling lots of move ctors + dtors.

If you have a move-only type, or a type that can be moved but cannot be 
Q_MOVABLE_TYPE (and not just because of QList BiC, which Q_RELOCATABLE_TYPE 
will fix), better use std::vector to hold it.

Thanks,
Marc

-- 
Marc Mutz <marc.mutz at kdab.com> | Senior Software Engineer
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