Re: [Boost-users] Delegating to boost::function with arbitrary signature

Subject: Re: [Boost-users] Delegating to boost::function with arbitrary signature
From: TONGARI J (tongari95_at_[hidden])
Date: 2013-12-16 10:31:04

2013/12/16 Alexander Lamaison <awl03_at_[hidden]>

> TONGARI J <tongari95_at_[hidden]> writes:
>
> >  template<typename Signature>
> >  class library_function
> >  {
> >  public:
> >      library_function(
> >          shared_ptr<HMODULE> library, Signature* library_funtion)
> >          :
> >      m_library(library),
> >      m_function(library_function)
> >      {}
> >
> >      operator Signature*() const { return m_function; }
> >
> >
> >  private:
> >      shared_ptr<HMODULE> m_library;     Signature* m_function;
> >  };Note: code not tested
>
> This works well.  The key was `operator Signature*()`.  Clever idea,
> thanks!
>
> I didn't expect it to work because I though `boost::function` would pull
> out the `Signature*` via the cooersion operator, and then the
> `library_function` would be destroyed before the call was made.
> However, this code proves that it has the desired behaviour, so it must
> be keeping a copy of the `library_function` instance inside
> `boost::function`: http://ideone.com/BZvuk9.
>
> I didn't use`make_library_function` because inferring the signature
> from the raw function isn't something I need.
>
> If you would like to add this answer to the Stack Overflow qusetion,
> I'll happily give you the brownie points :)
>

Done: http://stackoverflow.com/a/20614403/2969631

BTW, the reason why I knew this trick is because I implemented this:

    http://tinyurl.com/mptekbr

and it credits to Proto.