Re: [boost] has_member_fnc?

Subject: Re: [boost] has_member_fnc?
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2012-03-16 14:29:44

Olaf van der Spek wrote:
> On Fri, Mar 16, 2012 at 4:07 PM, Stewart, Robert
> <Robert.Stewart_at_[hidden]> wrote:
> > Neal Becker wrote:
> >>
> >> It seems c++11 has a new way to spell enable_if, and this
> >> can be used to implement has_member_fnc, as in this example:
> >>
> >> http://pastebin.com/mH2cZ4NP
> >
> > I wish I could see the code, but pastebin is blocked here.
>
>     //Special template for EE_PDUs, which are weird
>     template <typename T>
>     auto getKey_imp(const T &struc, int &key, int) ->
>        //If struc has an interesting_member member, this
>        //version is used
>        decltype(struc.interesting_member, void())
>         {
>             key = 0;
>         }
>         template <typename T>
>         void getKey_imp(const T &struc, int &key, long)
>         //struc didn't have an interesting_member member, do
>         //nothing
>         {
>         }
>
>     public:
>         template <typename T>
>         bool getKey(const T &struc, int &key)
>         {
>             getKey_imp(struc, key, 0);
>             return key == 0;        //Successful?
>         }

Thank you.

Did I miss something?  That just tests for a member by name.  To test for a member function, you'd need to specify the signature to make it worthwhile.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer                     using std::disclaimer;
Dev Tools & Components
Susquehanna International Group, LLP  http://www.sig.com

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