How to actually implement the rule of five?

Question

UPDATE at the bottom

q1: How would you implement the rule of five for a class that manages rather heavy resources, but of which you

Answer 1

Let me help you:

#include 

class AnObject
{
public:
  AnObject( size_t n = 0 ) : data(n) {}

private:
  std::vector data;
};

From the C++0x FDIS, [class.copy] note 9:

If the definition of a class X does not explicitly declare a move constructor, one will be implicitly declared as defaulted if and only if

• X does not have a user-declared copy constructor,

• X does not have a user-declared copy assignment operator,

• X does not have a user-declared move assignment operator,

• X does not have a user-declared destructor, and

• the move constructor would not be implicitly defined as deleted.

[ Note: When the move constructor is not implicitly declared or explicitly supplied, expressions that otherwise would have invoked the move constructor may instead invoke a copy constructor. —end note ]

Personally, I am much more confident in std::vector correctly managing its resources and optimizing the copies / moves that in any code I could write.