The example below shows a technique for perfect forwarding that seems to work with GCC 3.3.1. rvalues are always moved automatically, and lvalues are copied. Except for one rather important case, it works with Comeau (errors only in strict mode). The important case that causes the error clearly violates 12.2/1 of the standard, but see below. VC++ and CodeWarrior have different kinds of problems with it from Comeau/strict. I am hoping that they are wrong, but I am not enough of a core language jock to make a determination on which of these compilers is correct (if any). 12.2/1 says that the act of binding an rvalue to a (const) reference creates a temporary (which may be elided). The creation of the temporary requires the existence of a copy ctor with a const& argument. As far as I know, that rule serves no useful purpose, but I may have missed something. *If* my example actually works other than this case, I'd like to try to get the rule lifted, and soon! This is by no means the cleanest route to move semantics, but it's probably the smallest "language extension" we'd ever need to get it, and might even be possible before C++0x Enjoy, Dave -- Dave Abrahams Boost Consulting www.boost-consulting.com