What Is Rvalue Reference

To better distinguish these two types we refer to a traditional c reference as an lvalue reference.

What is rvalue reference.

Provides the member constant value which is equal to true if t is a rvalue reference type. Rvalue references is a small technical extension to the c language. The behavior of a program that adds specializations for is rvalue reference or is rvalue reference v since c 17 is undefined. Let s play a bit with this new toy.

Lvalue reference and rvalue reference. It s like removing the const attribute in the second line above. They are primarily meant to aid in the design of higer performance and more robust libraries. A rvalue reference can refer to rvalues.

An rvalue reference is a compound type very similar to c s traditional reference. To declare a rvalue reference we need to specify two operator i e. 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. When the term reference is used it refers to both kinds of reference.

So the following snippet works like a charm. 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. Checks whether t is a rvalue reference type. C 0x has introduced a new type called rvalue reference denoted by placing a double ampersand after some type.

Const int ref 10. Such rvalue reference lets you modify the value of a temporary object. Otherwise value is equal to false. Here lvalueref2 is a lvalue reference so it cannot point to a rvalue.

Rvalue references are a feature of c that was added with the c 11 standard.