On Sun, Nov 4, 2012 at 11:28 PM, TONGARI <tongari95@gmail.com> wrote:
2012/11/5 Matt Calabrese <rivorus@gmail.com>
So, instead of specifying the return type when invoking the metafunction, it automatically defines an associated type "result_type," which a programmer could then check against if he or she desired. Again, your implementation may be more useful depending on the context, but this is something to consider.
In the case that return type is unimportant, just leave it as void, e.g.
can_be_called<F, void(Args...)>
BTW, the Boost.Generic Definition column in your page seems to use ",,," instead of "..." for VA, is that true?
Yes, that's true. The code in the documentation is pulled directly from the library code, which is tested, so what's documented should always be correct. That is also why in some of the documentation you might see workarounds or little bits commented out that I can't support yet). The reason it's ",,," and not "..." is because it's impossible to detect "..." in the preprocessor. On the other hand, ",,," can be detected by passing the data to a variadic macro and seeing if it contains a group of empty arguments in a row. -- -Matt Calabrese