Re: Sinkability considered harmful
- From: Tristan Van Berkom <tvb gnome org>
- To: Tim Janik <timj imendio com>
- Cc: Federico Mena Quintero <federico ximian com>, GTK+ development mailing list <gtk-devel-list gnome org>, muppet <scott asofyet org>
- Subject: Re: Sinkability considered harmful
- Date: Wed, 04 Jan 2006 11:04:43 -0500
Tim Janik wrote:
Actually (to throw a wrench in things), the floating flag *does* make
language bindings easier. The GtkObject wrapper can *always* do an
unconditional ref and sink; if it was floating, e.g., returned from a
constructor, the object is now owned by the wrapper, and if not, the
wrapper is just another owner. For non-floating objects, the binding
author must now distinguish constructors from other functions in order
to avoid leaking objects. Gtk2-Perl has seen a lot of reference-count
leaks related to GObject-returning functions that we marked
incorrectly (human error), but none related to GtkObject-returning
That said, the main impetus for the human error involved in marking
API functions has been the inconsistency of ownership for returned
objects, that is, violation of the Principle of Least Surprise. It's
not cool to have to look at the reference docs for every single
function to verify whether you need to unref the return value.
ok, thanks for the insight. sounds like LBs will also benefit from sinkable
GObjects in the long run then.
GtkObject is a special case, it means that in your
binding you have to distinguish it from a GObject and treat
it differently, if there were no floating flag; you wouln't
need to do this.
If OTOH, you call a function like:
you cant count on the returned "bar" to be owned by you,
maybe it would be nice if functions returning internal
objects were to return "const" to clarify that.
either way; the fact that some functions dont return
a reference and some do is irrelevent to floating
objects, if it can happen with a GObject; it can happen
with a GtkObject.
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