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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c++
Subject: Re: Problem solved: forward variable number of arguments precisely to a template method
Date: Wed, 18 Sep 2019 08:22:21 -0700
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Pavel <pauldontspamtolk@removeyourself.dontspam.yahoo> writes:

> I just realized the problem was solved (not by me but by a high-class
> C++ expert who is a colleague of mine, to my luck).  The below solution
> works with gcc 4.8.5.  The key is to apply "Identity" pattern to the
> variable parameter type list and provide more information for type
> deduction.  [...]
>
> [ and the key part is ]
>
> template<class T>
> struct Identity {
>   using type = T;
> };
>
> template <class T, const int>
> struct Caller {
>   Caller(T& to):  o(to) {}
>   T& o;
>   template<class... A>
>   void callMethod(void (T::*m)(A...), typename Identity<A>::type... args) {
>     (o.*m)(args...);
>   }
> };

Interesting.  It took me a while to figure out what's going on
and why this works.  At first it looked exactly backwards, but
in retrospect it makes sense.  Kudos to your colleague.