> Using callback3_exn should catch any exceptions thrown in the code and 
> return. However, when the caml code throws an exception, my code doesn't 
> get control and the program terminates! I don't understand what's wrong 
> here -- could somebody please help?

Works fine here (in OCaml 3.00).  Make sure you use OCaml version 2.03
or later, since the initial implementation of callback*_exn in 2.02
was buggy.

If that doesn't explain your problem, please write caml-bugs@inria.fr
or use the bug-tracking system on our Web site and send us a complete
example reproducing the problem.

- Xavier Leroy