Re: Static member functions in VC

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From: Gnum (no-email_at_mail.boo)
Date: 05/11/04

  • Next message: sklett: "Re: determining what a ptr is pointing to" 
    Date: Wed, 12 May 2004 09:20:01 +1200

    You're right of course.
    What I want to achieve is NON static member function to be assigned as
    Callback procedure.
    It is exactly right that it HAS TO contain pointer to an object itself.
    One again you're right it is NOT standard C++ pointer as it is implemented
    in Borland C++ Builder by special way as Igor Tandetnik suggested here.
    And you're right it is like .Net delegate.

    My question was HOW TO say VC++ to handle it with no requiring me to write
    fancy macros and handle it manually.
    I do know how to do it, but I don't want to waste my time before I ensure
    there is no other way around.

    By the way. Thank you all guys! Now i know that I HAVE TO handle it bymeself
    as Microsoft hasn't implemented any common solution of this problem in VC++
    6.0 OR it is hidden so far that I will never know about it.

    Cheers!
    Gnum

    "Doug Harrison [MVP]" <dsh@mvps.org> wrote in message
    news:0jb2a0tkvtb3u4uucv5ndn5n37apq23d31@4ax.com...
    > Gnum wrote:
    >
    > >I've got a problem:
    > >
    > >====================================================
    > >typedef void FOnEven( int );
    > >
    > >class clsA
    > >{
    > >private:
    > >public:
    > > FOnEven* OnEvent;
    > >};
    > >
    > >class clsB
    > >{
    > >private:
    > > clsA* A;
    > >public:
    > > clsB();
    > > static void Event( void );
    > >}
    > >
    > >clsB::clsB()
    > >{
    > > A = new clsA();
    > > A->OnEvent = Event;
    > >}
    > >
    > >void clsB::Event( void )
    > >{
    > > From inside this function I can't see Data members of the object as
    > ><this> point is not defined here.
    > > However in Borland C++ Builder this construction allows me to see
    them.
    >
    > That can't be. The "this" pointer is not available inside static member
    > functions like "Event". Period. Mario gave you one possible workaround.
    >
    > > I can't realize how to implement the same ability in MS Visual C++.
    > > I don't want to write long tricky and looking weird things to get
    around
    > >this restriction to assign
    > > only STATIC functions pointers to variables like my FOnEven* OnEvent;
    > >
    > > Does anyone know some general solution?
    > > I wish there was a tickbox in settings to say "Allow assign NOT
    STATIC
    > >member functions to CALLBACKs"
    > >}
    >
    > Are you sure you're not confusing normal function pointers with pointers
    to
    > (non-static) member functions? Normal C++ pointers to members don't
    contain
    > an instance pointer. However, you can create a class that encapsulates an
    > instance pointer and a pointer to member function, which would then be
    much
    > like a .NET delegate. Maybe C++ Builder provides something like that? If
    so,
    > then your "Event" function would be a non-static member function.
    >
    > --
    > Doug Harrison
    > Microsoft MVP - Visual C++

  • Next message: sklett: "Re: determining what a ptr is pointing to"

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