CODEWITHSUNDEEP
c++c++11move-semantics
Chameleon
Chameleon

Reputation: 2137

Move semantics between base classes

We have these classes:

struct Intermediate : public std::array<double,3> {};

struct Vector3 : public Intermediate
{
   // ........more ctors.........

   // Modified move constructor (base class)
   Vector3(std::array<double,3> &&v) { ??????? }

   // ........more functionality...........
};

Is the "modified" move constructor act like original move constructor?

How can I implement the constructor? Is there another way than std::array::swap?

Upvotes: 0

Views: 277

Answers (1)

Jonathan Wakely
Jonathan Wakely

Reputation: 171263

You could do this:

Vector3(std::array<double,3> &&v)
{ static_cast<std::array<double,3>&>(*this) = std::move(v); }

This move-assigns v to the base class of this

But that move constructor seems pretty pointless. When you move an array of double it will just do a copy anyway. double has no move semantics, only copy semantics, and array<double,N> contains the array directly within it, so cannot move it to another object.

Upvotes: 2

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