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Date: Sat, 25 Feb 2006 01:09:35 +1300
From: "Jonathan Roewen" <jonathan.roewen@gmail.com>
To: OCaml <caml-list@yquem.inria.fr>
Subject: [Caml-list] signals & threading
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	version=3.0.3

Here's some example code once posted on the list to have a timeout.

let set_timer tsecs =3D
  ignore (Unix.setitimer Unix.ITIMER_REAL
                         { Unix.it_interval =3D 0.0; Unix.it_value =3D tsec=
s })

exception Timeout

let handle_sigalrm signo =3D
  print_string "Continue for how long? "; flush stdout;
  let f =3D read_float() in
  if f <=3D 0.0
  then raise Timeout
  else set_timer f

let continueq f arg tsecs defaultval =3D
  let oldsig =3D Sys.signal Sys.sigalrm (Sys.Signal_handle handle_sigalrm) =
in
  try
    set_timer tsecs;
    let res =3D f arg in
    set_timer 0.0;
    Sys.set_signal Sys.sigalrm oldsig;
    res
  with Timeout ->
    Sys.set_signal Sys.sigalrm oldsig;
    defaultval

Now, my question is: what happens with multiple threads? The exception
is raised in whatever thread is currently running? Is there also no
control over such behaviour?

Jonathan