[ocaml-ctypes] Spinning process on osx

[Daniel Bünzli]

This thing is driving me crazy. In fact I reached to wrong conclusions about 4.00.1. The problem also exists there. I realized by running some programs for long enough, eventually they'd always exit with bus error 10. 

I now have a short repro case that works for both 4.00.1 and 4.01.1 [1]. It exits with bus error 10:

Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000100c4f3e8

after entering the loop. I checked that a corresponding pure C program has no problem.

I rechecked the bindings of all the functions used until error [2]. Note that just adding something like a printf statement to the loop may make the program work (or at least for a longer time).

I'm at loss.

Daniel


[1]
-----min.ml-------
(* 
    Minimal OCaml SDL example. This code is in the public domain. 
    Compile with:
    ocamlfind ocamlc -package tsdl -linkpkg -o min.byte min.ml
    ocamlfind ocamlopt -package tsdl -linkpkg -o min.native min.ml
*)

open Tsdl

let main () = match Sdl.init Sdl.Init.video with 
| `Error -> exit 1
| `Ok () -> 
    match Sdl.create_window ~w:640 ~h:480 "SDL OpenGL" Sdl.Window.opengl with 
    | `Error -> exit 1
    | `Ok w ->
        Printf.printf "Enter%!";
        while true do Sdl.gl_swap_window w done;
        Sdl.destroy_window w; 
        Sdl.quit (); 
        exit 0

        let () = main ()
--------------------

[2]
https://hg.libsdl.org/SDL/file/e749005cfd72/include/SDL.h#l129
https://github.com/dbuenzli/tsdl/blob/master/src/tsdl.ml#L187

https://hg.libsdl.org/SDL/file/e749005cfd72/include/SDL_video.h#l408
https://github.com/dbuenzli/tsdl/blob/master/src/tsdl.ml#L1675

https://hg.libsdl.org/SDL/file/e749005cfd72/include/SDL_video.h#l959
https://github.com/dbuenzli/tsdl/blob/master/src/tsdl.ml#L1986