David Abrahams wrote:
Andrea Torsello <torsello@dsi.unive.it> writes:
[snip]
Yes, actually different compilers seem to act differently here. Since the compiler is free to copy const rvalues to non-const rvalues and optimize the copy away, I would consider returning a const temporary an odd thing to do. I am curious: does anyone have a use-case for it?
I doubt it; it doesn't seem like a very important case. It could be used to have some effects on overload resolution I suppose, but it's hard to imagine that being useful in real code.
Just a comment on the 'const temporary return' issue. I'd say it's not really an issue of whether it's useful per se, but how it is _actually used_ in real code as a "safety" feature. I.e to prevent: (a*b) = c; Scott Meyers' Effective C++, item 21, labels this "The Right Thing To Do". I've seen similar recommendations in a couple of coding-guidelines and several times in real code, most likely inspired by EC++ or similar. Thus it will appear in real code if nothing else for a matter of style. // Fredrik Blomqvist