Returns the vector <vector <int>> from a function that calls any move constructors in C ++ 11

Question

Does C ++ 11 return vector<vector<int> >from a function that calls any move constructors? Or will the code below make another copy of all the vectors and their elements?

vector< vector<int> > Func() {
  vector< vector<int> > vec;
  //vec is filled here
  return vec;
}

For stl containers of simple types, is there anything in common to determine when a move constructor is used or when copying is performed when returning them as values ​​from functions?

Answer 1

Operators

returnspecially covered by the standard, which is automatically treated as movement. So yes, this will call the move constructor.

- ++ 11, [class.copy]§31+32:

31 , / ... /, , ( ):

• return , ( catch-clause) cvunqualified , , / ,
• ...

32. , , , lvalue, , , , rvalue. rvalue (, cv-qualit), , lvalue....

( )

, , , , .

(, @BjornPollex, , )