Yesterday I made the spot decision to make the move from building Gnocl against the Gtk2+ libraries to Gtk3+. At the end of the day I got the bulk of the gnocl::window module running. This doesn't mean that the conversion process will be an easy journey, it won't. The current build of Gnocl has evolved over the years and contains many legacy calls to widgets, functions, structures and macros not longer supported in Gtk3+. The immediate effect is that much of the 'glitzy' stuff working on pixmaps no longer work. Its all a question of time!
This doesn't mean that the Gtk2+ distribution will be forgotten, it still forms the backbone of the project and will be supported till most the the conversion work has been done.
One of the greatest challenges is the lack of suitable documentation. For Gtk2+ there was always Krause's excellent book, but now the emphasis would appear to be upon creating chunks of builder xml code and embedding these as strings into C-sourcecode.
It would appear though, that there's always more than one way to skin a cat, and, getting the initial 'application' running was not, shall we say, according to the manual. Actually, by working around the rules, it became simpler!
It'll be some time before a first workable, package is released, so until then, wish me luck and straightforward coding!