Hello.

On Wed, Mar 23, 2016 at 12:50 PM, Goswin von Brederlow <goswin-v-b@web.de> wrote:

I'm stuck with a bug in the Tetrix example for my QT5 bindings:

https://github.com/mrvn/ocaml-qt5

The segfault happens when you click start and the first piece is moved
one tile down in caml_mrvn_QT5_OPainter_fillRect. The arguments to the
call all look ok but something must corrupt the painter. The segfault
goes away when I force a Gc.full_major before creating a new OPainter
in TetrixBoard:148.

Just a wild guess: there are a lot of raw c++ pointer casts to ocaml values in the code, and to quote http://caml.inria.fr/pub/docs/manual-ocaml/intfc.html#sec424 "this can crash the garbage collector" in some non-obvious circumstances.