What Is Rvalue Reference

Checks whether t is a rvalue reference type.

What is rvalue reference.

Invalid initialization of non const reference of type int from an rvalue of type int gcc complains about the reference not being const namely a constant. Provides the member constant value which is equal to true if t is a rvalue reference type. Let s play a bit with this new toy. Rvalue references are a feature of c that was added with the c 11 standard.

According to the language specifications you are allowed to bind a const lvalue to an rvalue. To declare a rvalue reference we need to specify two operator i e. Const int ref 10. When the term reference is used it refers to both kinds of reference.

Rvalue references are introduced in c 11 and rvalue references can do what lvalue references fails to do i e. A rvalue reference can refer to rvalues. Lvalue reference and rvalue reference. The behavior of a program that adds specializations for is rvalue reference or is rvalue reference v since c 17 is undefined.

Otherwise value is equal to false. Rvalue references is a small technical extension to the c language. To better distinguish these two types we refer to a traditional c reference as an lvalue reference. They are primarily meant to aid in the design of higer performance and more robust libraries.

C 0x has introduced a new type called rvalue reference denoted by placing a double ampersand after some type. It s like removing the const attribute in the second line above. An rvalue reference is a compound type very similar to c s traditional reference. What makes rvalue references a bit difficult to grasp is that when you first look at them it is not clear what their purpose is or what problems they solve.

Such rvalue reference lets you modify the value of a temporary object.