Re: [Boost-users] [FunctionTypes] Testing for a general callable type.

Subject: Re: [Boost-users] [FunctionTypes] Testing for a general callable type.
From: Jeffrey Lee Hellrung, Jr. (jeffrey.hellrung_at_[hidden])
Date: 2013-03-25 16:48:00

On Mon, Mar 25, 2013 at 12:22 PM, Nevin Liber <nevin_at_[hidden]>wrote:

> On 22 March 2013 08:15, TONGARI <tongari95_at_[hidden]> wrote:
>
>>
>> https://github.com/jamboree/boost.has_call
>>
>
> It doesn't seem to work with default arguments. :-(
>
> Here is my test case (under gcc 4.7.2 -std=c++0x):
>
> #include "boost/type_traits/has_call.hpp"
> #include <cassert>
>
> template<typename Sig, typename F>
> bool HasCall(F const&)
> { return boost::has_call<F, Sig>::value; }
>
> void DefaultVal(int = 0) {}
>
> int main()
> {
>     assert(HasCall<void()>(DefaultVal));
> }
>

That's because the type of DefaultVal is void ( int ). Function types
cannot encode the default'ness of parameters.

- Jeff