It looks to me like the problem is the binds using shared_ptrs as
instance pointers. Boost.Bind takes a copy of the shared_ptr while
constructing the bind object (which is used to construct the funcion
object). You then pass the function object to the GUI/event handler,
which then contains a shared_ptr to the event handler/GUI respectively
- as a shared_ptr is an ownership link, that this means that the GUI
'owns' the event handler and vice versa.
An option would be to perform those binds using raw pointers - for
example, use m_gui.get() rather than just m_gui. That would prevent
the 'ownership' links being created. The smart pointer library *does*
offer weak_ptr as a non-owning smart pointer, but I don't know if
Boost.Bind works with that - worth investigating, though?
HTH
Stuart Dootson
On Sat, Jul 12, 2008 at 12:14 PM, Simon Pickles
Hello,
I am using boost::functions to provide a simple event system, but have come across a problem.
I have two classes that need to communicate with each other, CGUI and CEventHandler. Their instances are both shred_ptrs owned by a third class, CCore.
<snip>
As you can see, CCore binds a public member function of m_gui and passes it to the eventhandler, where it is stored and used to send events.
The event handler returns its own member function, bound to this, which CCore duly passes to m_gui.
Now both classes hold objects with refs to each other, and the program does a big memory dump when it is ended, on win32 with MSVC2005. I envisage this is because the shared_ptrs holding the instances of CGUI and CEvenHandler are not destructing at program close.
Commenting out the line: m_guiTx = f;
eliminates the issue.
What is a better way to achieve this?
Thanks
Simon