At Sun, 20 Jun 2010 18:46:16 +0200, Thomas Klimpel wrote:
Boost.Parameter does a very good approximation of perfect forwarding, generating T&/T const& parameters for all out- and in/out- parameters. It does erase rvalue-ness, but that's pretty much a given with C++03 that AFAICT nobody knows how to avoid.
In fact, Rutgers code doesn't erase rvalue-ness as well,
I think you mean *does*, right?
it was just me misinterpreting things. So what he does is really just a "perfect forwarding" emulation, just as Boost.Parameter does. However, I wonder whether Boost.Parameter uses the preprocessor to implicitly generate a similar amount of code as Rutgers solution explicitly generates.
Well, Boost.Parameter has the advantage of knowing which parameters need to be passed by non-const reference, so unless all your parameters are “out” or “in_out” parameters, it probably does better than Rutger's solution.
In that case, I would wonder whether it would be possible to selectively turn off the T const& overload for parameters that don't need it (so that we could still use the "workaround" mentioned above).
Why would you want to turn that one off, as opposed to the T& one (as Boost.Parameter does)? Seems kinda crazy. -- Dave Abrahams BoostPro Computing http://www.boostpro.com