I observe the following unexpected behavior:<div><br></div><div>--- <a href="http://a.ml">a.ml</a> ---</div><div><div>try</div><div>  … some code ...</div><div>with e -&gt;</div><div>(*  Printf.eprintf &quot;%s\n&quot; (Printexc.to_string e); *)</div>

<div>  Printexc.print_backtrace Legacy.stderr</div></div><div>------</div><div><br></div><div>Compiling as ocamlopt -g <a href="http://a.ml">a.ml</a> gives:</div><div>$ ./a.out</div><div>Raised at file &quot;<a href="http://fool.ml">fool.ml</a>&quot;, line 162, characters 13-22</div>

<div>Called from file &quot;<a href="http://bar.ml">bar.ml</a>&quot;, line 13, characters 5-56</div><div>Called from file &quot;<a href="http://bar.ml">bar.ml</a>&quot;, line 43, characters 4-63</div><div><br></div><div>
Now this doesn&#39;t say which exception was raised, so I uncomment the commented line. I&#39;m expecting the identical output, but with the exception printed first. However, I get:</div>
<div><br></div><div><div>$ ./a.out</div><div>Not_found</div><div>Raised at file &quot;<a href="http://hashtbl.ml">hashtbl.ml</a>&quot;, line 93, characters 19-28</div></div><div><br></div><div>So it appears that printing an exception changes the backtrace. Is that possible?</div>

<div><br></div><div>Unfortunately, I cannot reproduce this behavior in a minimal example. The following script behaves as expected:</div><div><br></div><div>--- <a href="http://b.ml">b.ml</a> ---</div><div><div>let f () = raise (Failure &quot;&quot;)</div>

<div>let g () = f ()</div><div>let _ =</div><div>  try g()</div><div>  with e -&gt;</div><div>    (* Printf.eprintf &quot;%s\n&quot; (Printexc.to_string e); *)</div><div>    Printexc.print_backtrace stderr</div></div><div>

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