Restriction on interface function types

[Steve Teale]

On Wednesday, 12 March 2014 at 14:28:02 UTC, Steven Schveighoffer 
wrote:
> > I saw that, but I think what you encountered was a bug in the
> compiler or differently-generated vtables. I think you should 
> focus on trying to identify and fix the bug rather than trying 
> to exploit a workaround.
>
> One thing to try is re-compiling all your code. Any changes in 
> vtables will mess up the linkage. If the compiler thinks your 
> function to call is in index 2 in one compilation, but it's in 
> index 3 in another, bad things will happen :)
>
Steve,

Recompilation has been frequent, and the makefile for the plugin 
refers to the sources for the app, and is otherwise just a single 
source file, so I don't think it is that.

My primary suspicion is that I am linking both the plugin and the 
app using the static gtkd-2 library. I believe the next step is 
to link both against a shared library version of gtkd-2. So far, 
I've had no success in building that. If the library code has 
static module constructors/destructors, or some such alternative 
down at the GTK+3 OOP C level, that uses a distinct text or data 
segment or something, then I can understand that I might well be 
hosed.

It's also noteworthy that I can't use an interface as a 'base 
class' for the plugin, even though the system should work with 
quite a limited set of methods. That works to the extent that 
methods that don't access data work OK, but if they do, the 
edifice comes tumbling down.

I'll have to brush up my command-line GDB skills to get much 
further - something I'm not looking forward to. Last time I did 
it was pre Iain Bucklaw when I was trying to sort out crashes in 
GDC.

The ability to dynamically load D shared libraries into a D 
program is something that's been way up my wish list since about 
2006. Seems like there's some way to go yet. Even further for 
Windows, where we probably need a new linker!

At present, the app seems to be working pretty well with a 
plugin, as I have special cased the calls to host.onCSNotify() 
etc to apply the cast when the target is my main base class. 
Other uses will generally be entirely local to a plugin. So it 
might just stay like that for a while until I break it again.

Thanks
Steve