Version française
Home     About     Download     Resources     Contact us    
Browse thread
[Caml-list] OCam'OLE pre-release
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: -- (:)
From: Nicolas Cannasse <warplayer@f...>
Subject: Re: [Caml-list] OCam'OLE pre-release
> > The job of the GC is to release unreferenced objects.
> > But I don't see how this can cause a bug : it seems that your crash is
due
> > to a call of a COM method on a object AFTER it has been released... if
it
> > has been Release, then it is no longer referenced by Ocaml... so , how
can u
> > ever call a method on it ???
>
> Because the COM object can still be referenced from C.  You probably
> forgot to do an AddRef somewhere, e.g. when extracting a COM object
> reference from its Caml wrapper.
>
> Reference count management sure is tricky...

True.
If you're using OCamole to manipulate COM objects and then passing them back
to C, your C code need to call AddRef on the retreived COM object since
OCamole GC'ed process does not respect the COM spec (caller is responsible
from Release, callee call AddRef )

Simply use the following function :

IUnknown *get_com_object( value v ) {
    IUnknown *o = IUnknown_val(v);
    o->AddRef();
    return o;
}

Nicolas Cannasse

-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners