Re: [win32gui] [perl-win32-gui-hackers] Commit

[Robert M. <rm...@po...>]

Jeremy White wrote:
>> Just one comment here - if the parent doesn't have valid userdata, 
>> should GetParent() return the hwnd, like most other calls do?  Should 
>> we be looking at extending/changing other api calls to return objects, 
>> where such objects exist?

> Both good questions and the honest answer is that I don't know:) 
> Personally I prefer using objects, but if we have methods that could 
> return either then it would mean that the user would have to test the 
> return value before each use.

I think that's good logic to use to say that a method should return 
either object/undef or handle/undef, but never object/handle/undef.

> In theory 
> you should be able to create a sell referencing window, which has no 
> global reference, with the window controlling when it's destroyed. 
> Something like this:
> 
> {#window constructor
> my $win=create window;
> #the window is stored within itself, and the ref count is increased and 
> wont be destroyed when
> #the block is finished
> $win->UserData($win);
> }
> 
> onTerminateHandler
> {
> my $self=shift;
> #Setting the userdata to a blank string causes the ref count to be 
> dropped on the window
> #and therefore should kick in the destruction logic
> $self->UserData('');
> }

Have you tried this?  It's sort of equivalent to

}
   my $mw;
   $mw = Win32::GUI::Window->new(
	...
	-onTerminate => sub { undef $mw },
   );
}

Which uses a closure to stop $mw's ref count going to zero at the end of 
the enclosing block, but forces it to zero in the onTerminate handler.

> Ok - I'll add these scripts later. Does anyone know a way to test for 
> memory leaks?

No idea how to test for memory leaks - it's such a hard problem that 
there's a whole industry around making tools to do just that.

You'll find developer CVS is down for anything up to the next 36 hours 
for maintenance.

Regards,
Rob.