C++ move semantics from scratch (2022)

19 days ago

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Move semantics in C++ are introduced to solve inefficiencies in copying large data structures by enabling 'stealing' data from one object to another.
Rvalue references (&&) are introduced in C++11 to distinguish between objects that can be moved from (temporary or about to be destroyed) and those that cannot (lvalue references).
The std::move function is a utility that casts an object to an rvalue reference, signaling that it can be moved from, but it doesn't perform the move itself.
Move semantics are convention-based; the language encourages moving from rvalue references and copying from lvalue references, but this is not enforced by the compiler.
Use-after-move is a common pitfall in C++ where an object is used after its resources have been moved, leading to undefined behavior.
Alternatives to C++ move semantics include C's explicit move functions and Rust's move-by-default with explicit copies, which offer different trade-offs in safety and complexity.

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