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This article introduces the knowledge of "Why C++ should not return to the right reference obtained from local variables using std:move". Many people will encounter such a dilemma in the operation of actual cases, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

F.48 do not return right-value references obtained from local variables using std:move

Reason (reason)

Currently, explicit use of std::move in return statements is almost the worst way to ensure that copy actions are omitted.

Translator's note: copy elision is called copy ellipsis or translation of "omitting unnecessary copies", which is a very important optimization technique.

Example, bad (negative example) SF () {S result; return std::move (result);}

Translator's note: the use of std::move to forcibly avoid copy actions is not recommended.

Example, good (good example) SF () {S result; return result;} translator's note: the latter takes advantage of the return value optimization (Return value optimization, abbreviated to RVO) function, which is a compilation optimization technique of C++.

Enforcement (implementation recommendations)

This guideline should be enforced and instrumented.

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