Hi,
In file vorbis_stubs.c, function copy_buffer:120: CAMLparam/local was used but there is no CAMLreturn on this branch
Just a small comment on this one: this is a "false alarm". It is never called directly from caml. It's only called within vorbis_stubs.c and its result is always CAMLreturned, so... I can imagine it's harder for inter-procedural checks and I don't know how precise your tool is supposed to be.
Regards, Samuel.
