On Wednesday 26 June 2002 6:16 pm, Andre Poenitz wrote:
> On Wed, Jun 26, 2002 at 05:59:24PM +0100, Angus Leeming wrote:
> > > I have a cached 'BufferView *' already anyway.
> >
> > Which becomes unsafe as soon as we start creating and destroying multiple
> > buferviews?
>
> Probably.
>
> > Hence my thoughts on using a signal to invoke the update...
>
> And I still have not understood that signal stuff. Call me dumb...
In this case it's easy.
class A {
void Func1(B const & b);
void Func2(...);
boost::signal0<void> Signal1
};
class B : boost::trackable {
void someConnectingFunc()
};
The idea: A::Func2 is going to be called at some stage and what to invoke
B::someConnectingFunc for the instance B const & b that was passed to
A::Func1. Only A::Func2 doesn't remember what bv is unless A cache's it (your
way). Only A::Func2 HAS NO WAY of knowing whether this cached B* points to
anything anymore.
What to do?
Use a signal which (because B derives from boost::trackable) will just Do The
Right Thing.
A::Func1(B const & bv)
{
Signal1.connect(&B::someConnectingFunc, &bv);
}
A::Func2(...)
{
if (...)
Signal1();
}
I too have no idea about the internals of the boost signal stuff. I don't
need to ;-)
Angus
