Re: [sigc] Re: [Boost-users] Signals & Slots

[Murray Cumming <murrayc murrayc com>]

On Sat, 2005-01-08 at 06:05 -0500, Carl Nygard wrote:
> On Sat, 2005-01-08 at 09:23 +0100, Murray Cumming wrote:
> > On Fri, 2005-01-07 at 20:10 -0500, Carl Nygard wrote:
> > > sigc::connect() -- can it take a function object or ptr-to-function or
> > > must they be wrapped with sigc::ptr_fun() or sigc::mem_fun()?
> > 
> > You can use a pointer-to-function without using sigc::ptr_fun(). I
> > tested that just now.
> > 
> > A pointer-to-member-function without sigc::mem_fun() would be useless
> > without the object instance.
> 
> Yeah, but it can assume operator()() if given the address of a class
> object instance, in the case of a function object.  That's what I meant
> by "function object ... without... sigc::mem_fun()"?  Is that supposed
> to work, or is the explicit sigc::mem_fun() required?

Yes, this works:

class foo
{
  public:
  void operator()(int i)
  {
    std::cout << "foo(int "<< i << ")" << std::endl;
  }
};

int main()
{
  sigc::signal<void, int> sig;

  foo instance;
  sig.connect(instance);

  sig.emit(1);
}


Again, I am surprised. I'm not sure whether I like it, but I guess
people should be less surprised as they get used to functors.

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com