C++11的new concepts (move semantic)

MoveConstructible 和MoveAssignable

MoveConstructible Specifies that an instance of the type can be move-constructed (moved). This means that type has move semantics: that is, can transfer its internal state to a new instance of the same type potentially minimizing the overhead.

The type must meet CopyConstructible requirements and/or implement the following functions:

Type::Type( Type&& other );

Type::Type( const Type&& other );  

Type::Type( volatile Type&& other );

Type::Type( const volatile Type&& other );  (One of the variants is sufficient)

&&表示rvalue reference.

Move constructor: constructs an instance of a type with the contents of other. The internal state of other is unspecified after the move. However, it must still be valid, that is, no invariants of the type are broken.

The following expressions must have the specified effects:

Type a = rv;  a is equivalent to rv, where rv is a rvalue reference of Type.   

Type(rv);  a temporary object of type Type is equivalent to rv, where rv is a rvalue reference of Type.