Move Semantics and Rvalue References

Move semantics is one of the most important features C++11 gave us—it makes "transferring ownership of resources" a first-class citizen and has completely changed how we deal with the cost of copying. In this chapter we start from the value category system, getting clear on what an lvalue is, what an rvalue is, and why we need rvalue references; then we dig into how move construction and move assignment are actually implemented, sort out how the special member functions of the Rule of Five fit together, and see how much work the compiler's RVO optimization saves you; next, perfect forwarding ties everything together; and finally we land on two articles of hands-on practice: the payoff from standard library containers with measured benchmarks, and how to bring moves into your own types. Move semantics isn't just a performance optimization—it is the cornerstone of understanding resource management in modern C++.

Chapter Contents

STARTFINISHRvalue References: From Copy to Move→STARTFINISHMove Construction and Move Assignment→STARTFINISHThe Rule of Five: How the Special Member Functions Fit Together→STARTFINISHRVO and NRVO: The Compiler's Return Value Optimization→STARTFINISHPerfect Forwarding: Keeping Value Categories Intact→STARTFINISHMove Semantics in Practice: Standard Library Containers and Performance Benchmarks→STARTFINISHMove Semantics in Practice: Custom Types and Resource Handles→