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.

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. Rvalue references allow programmers to avoid logically unnecessary copying and to provide perfect forwarding functions. It s like removing the const attribute in the second line above. To declare a rvalue reference we need to specify two operator i e.

So the following snippet works like a charm. Here lvalueref2 is a lvalue reference so it cannot point to a rvalue. Rvalue references is a small technical extension to the c language. Let s play a bit with this new toy.

They are primarily meant to aid in the design of higer performance and more robust libraries. Lvalue reference and rvalue reference. When the term reference is used it refers to both kinds of reference. Provides the member constant value which is equal to true if t is a rvalue reference type.

Otherwise value is equal to false. Checks whether t is a rvalue reference type. Rvalue references are a feature of c that was added with the c 11 standard. A rvalue reference can refer to rvalues.

According to the language specifications you are allowed to bind a const lvalue to an rvalue. An rvalue reference is a compound type very similar to c s traditional reference. Such rvalue reference lets you modify the value of a temporary object. The behavior of a program that adds specializations for is rvalue reference or is rvalue reference v since c 17 is undefined.

C 0x has introduced a new type called rvalue reference denoted by placing a double ampersand after some type.