]> Hi, I would like to create different threads where each thread do some computation and are subject to different timeout. Without threads I usually use Unix.alarm with a SIGALARM handler that just raise a Timeout exception and everything works fine, but when I try to do something similar with threads it does not work because apparently the Unix.alarm done in one thread override the Unix.alarm done in another thread. I had a look at thread.mli but was not able to find anything related to timeout. Is there a way to have multiple timeout and multiple threads at the same time ? Here is a program that unforunately get the first timeout, but not the second :( (* ocamlc -g -thread unix.cma threads.cma signals_and_threads.ml *) exception Timeout let mytid () = let t = Thread.self () in let i = Thread.id t in i let set_timeout () = Sys.set_signal Sys.sigalrm (Sys.Signal_handle (fun _ -> prerr_endline "Time is up!"; print_string (Printf.sprintf "id: %d\n" (mytid())); raise Timeout )); ignore(Unix.alarm 1); () let main = let t1 = Thread.create (fun () -> set_timeout (); print_string (Printf.sprintf "t1 id: %d\n" (mytid())); let xs = [1;2;3] in while(true) do let _ = List.map (fun x -> x + 1) xs in () done; () ) () in let t2 = Thread.create (fun () -> set_timeout (); print_string (Printf.sprintf "t2 id: %d\n" (mytid())); let xs = [1;2;3] in while(true) do let _ = List.map (fun x -> x + 1) xs in () done; () ) () in Thread.join t1; Thread.join t2; () ------------------ Here is the output Time is up! t2 id: 2 t1 id: 1 id: 1 Thread 1 killed on uncaught exception Signals_and_threads.Timeout .... <the program loops, meaning the second thread never received its timeout