Re: [Boost-users] [type traits / MPL] check whether a class has a certain member function

Subject: Re: [Boost-users] [type traits / MPL] check whether a class has a certain member function
From: Stefan Strasser (strasser_at_[hidden])
Date: 2013-03-07 15:53:30

Am 07.03.2013 20:12, schrieb Jeffrey Lee Hellrung, Jr.:
>             The macro you're looking for is BOOST_TTI_HAS_MEMBER_FUNCTION.

>     it requires you to know the exact signature of the member
>     function. I'm trying to check whether it is ok to call c.f(x), which
>     would be satisfied by each of the following 3 signatures (and more):
>
>     struct C{
>          void f(X);
>          void f(X &);
>          void f(X const &);
>          ...
>     };
>
>     is there a way to check for that, or do I have to check for all
>     (likely) signatures?

> https://groups.google.com/group/comp.lang.c++.moderated/tree/browse_frm/thread/4f7c7a96f9afbe44/c95a7b4c645e449f?pli=1#doc_e5fbc9305539f699
>

Thanks!
it doesn't work for me, because it uses sizeof(void) if the function 
call is possible.

However, it is enough to determine whether a member of a given name 
exists, without checking the signature. an implementation of has_member 
is here: http://www.rsdn.ru/forum/cpp/2720363

Edward, can this be added to TTI, for example as BOOST_TTI_HAS_MEMBER?
not only does this implementation look portable to me, but boost already 
uses it internally: 
http://www.boost.org/doc/libs/1_47_0/boost/thread/locks.hpp

Stefan