Søren Lassen wrote:
The standard places some limits on when NAMED objects may be optimized away. From this follows implicitly that UNNAMED objects may always be optimized away. Or, to quote from Scott Meyers' "More Effective C++", page 109-110: "However, the fact remains that unnamed objects have
BTW, did you read Scott's errata? To quote from it: 109 Both the first and second implementations on this page suffer from the problem that they are returning whatever operator=+ returns. In general, there is no way to know what this is (yes, it's a reference to an object of type T, but a reference to which T object?), hence no way for compilers to optimize away the copy to operator+'s return value. The way to write operator+ such that the return value optimization can be performed is with this body: T result(lhs); result += rhs; return result. taken from <http://www.aristeia.com/BookErrata/mec++-errata_frames.html> Regards, Daniel