What is move semantics and when to use std::move?

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**Move semantics** — transfer resources instead of copying. ```cpp std::vector a = {1, 2, 3}; std::vector b = std::move(a); // a is now empty // b = {1, 2, 3} ``` **When to use std::move:** ```cpp // Returning local variables (NRVO may apply) std::vector create() { std::vector v = {1, 2, 3}; return v; // NRVO or move } // Transferring ownership void consume(std::string s); std::string name = "Alice"; consume(std::move(name)); // name is now in valid-but-unspecified state ``` **Don't move:** - Into functions taking `const&` - When you still need the value - Simple types (int, pointers) - Return values (let NRVO handle it)

C++: What is move semantics and when to use std::move?