On 9/4/2012 10:32 PM, Jeffrey Lee Hellrung, Jr. wrote:
In any case, I still think your use of result_of in the given example was brittle and, ultimately, a misuse, whether we're speaking of the TR1-based or the decltype-based result_of.
Yes.
AFAIK, result_of has never had any guarantees as far as instantiating it with invalid call signatures.
Correct. And in C++11, std::result_of doesn't make that guarantee either. From Table 53 in 20.7.6.6 describing the requirements of std::result_of: "Fn shall be a function object type (20.8), reference to function, or reference to function object type. The expression decltype(declval<Fn>()(declval<ArgTypes>()...)) shall be well formed." Joel, I know you're annoyed by this change. But in truth, you were relying on an implementation detail of result_of. The list of gotchas in the release notes will include this case. -- Eric Niebler BoostPro Computing http://www.boostpro.com