Well yeah, if you directly access low-level stuff, it's quite easy to make your program crash.

The point is... I'm not doing that. Gtk2hs is, but that's a well-tested library, so I very much doubt it's the source of the bug.

so how would a bug in GTK or in libpng demonstrate itself ? i'm wondering, wouldn't it be a segfault ?
does just wrapping them in some fancy haskell typed functions turn every library into a safe, typed haskell code ?