Gain insights into the C++ keyword 'const,' its usage in various contexts, and implications when returning pointers and references. Learn about preventing accidental data changes.

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In this course, you will learn about the C++ keyword const and its behaviour under different usage conditions, including local, global and static contexts. This course will help you to understand const and its implications when you attempt to return pointers and references in C++. By the end of the course, you will have a solid grip on const and its usage in preventing any accidental change of data.

Secure Coding Practices in C++: A Deep Dive into const

# When to use const rvalue references?

An lvalue overload can accept both lvalues and rvalues, but an rvalue overload can only take rvalues. 

The goal of rvalue references is sparing copies and using move semantics. At the same time, we cannot move away from `const` values. Therefore the usage of `const` rvalue references communicates that a given operation is only supported on rvalues, yet we can still make a copy because we cannot move.

What is important to note is that `f(const T&&)` can take both `T&&` and `const T&&`, while `f(T&&)` can only take the non-`const` rvalue reference.

Therefore if we want to stop using rvalue references completely, we need to delete the `f(const T&&)` overload.

# What would happen otherwise?

If we delete the non-`const` overload, the compilation will fail with rvalue references. Although it doesn’t make much sense in general to pass `const` rvalue references, the code will still compile.

Let’s learn when to use const rvalue references.


Use of const Rvalue References

Let’s learn when to use const rvalue references.

Introduction

Arguments using const

Local Variables

Local Members

Functions

Return Types

const Parameters

const and Smart Pointers

Rvalue References

Summary

Use of const Rvalue References

When to use const rvalue references?