Re: [boost] Move semantics for std::string?

2012/2/17 Robert Dailey <rcdailey@gmail.com>

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Simplified RVO rules: If all return statements in a function refer to the same local variable OR if a function returns an ravlue in all cases, the copy can (and in practice will) be elided.

// RVO-enabled: always returns the same local variable. string foo() { string res; if (flag) { res = "hello"; return res; } else { res = "bye"; return res; } }

// RVO-enabled: always returns a temporary. string foo() { if (flag) return "hello"; else return "bye"; }

It's a good practice to make all functions you write RVO-enabled.

So all of these functions are functionally equivalent to simply constructing a std::string object in the calling scope?

Yes.