Il 06/03/2018 01:42, Kevin Kofler ha scritto:
I would also like to point out that the actual gain of having an
append(QVector<T> &&) over the current append(const QVector<T> &) would be
very limited. At best you would save a pair of atomic integer operations.


No, because the former would move all elements.

template <typename T>
void QVector<T>::append(const QVector<T> &v)
{
    reserve(size() + v.size());
    std::copy(v.begin(), v.end(), std::back_inserter(this));
}

template <typename T>
void QVector<T>::append(QVector<T> &&v)
{
    reserve(size() + v.size());
    std::move(v.begin(), v.end(), std::back_inserter(this));
}

All this complexity of rvalue references and std::move in C++11 and newer is
only necessary because the STL containers are not implicitly shared.

Not at all, you may want to exactly the same for std::vector.

My 2 c,
--
Giuseppe D'Angelo | giuseppe.dang...@kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - The Qt, C++ and OpenGL Experts

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