Re: [Caml-list] Unix.wait: strange behavior

[Yang Shouxun <yangsx@fltrp.com>]

As a follow-up to my initial post, I found that the strange behavior is 
due to the difference of toplevel and byte-compiled. The code, when 
byte-compiled, will act as described in the book. When run at the 
interactive toplevel, acts as I reported.

That's a good lesson for me that there are big differences between the 
three different modes.

Yang Shouxun wrote:
> Hi,
> 
> I'm reading ocaml-book English version. On p. 611:
> ----8<----
> match Unix.fork () with
>     0 -> Printf.printf "fair Marquise " ; flush stdout
>   | _  -> ignore (Unix.wait ()) ;
>           match Unix.fork () with
>               0 -> Printf.printf "your beautiful eyes " ; flush stdout
>             | _ -> ignore (Unix.wait ()) ;
>                   match Unix.fork () with
>                       0 -> Printf.printf "make me die " ; flush stdout
>                     | _ -> ignore (Unix.wait ()) ;
>                    Printf.printf "of love\n" ;
>                    flush stdout
> ----8<----
> this is intended to show the use of Unix.wait to wait for the 
> termination of the child.
> 
> Strangely, when I input at the Ocaml toplevel, it does not print "fair 
> Marquise your beautiful eyes make me die of love", but only "fair 
> Marquise". The forked processes did not terminate for some reason, which 
> I don't understand why. Is this a bug?
> 
> Guessing that the child processes will not automatically exit, I added 
> "; exit 0" to the lines for newly forked processes, and I got "your 
> beautiful eyes make me die of love" printed before the return of the 
> expression and then "fair Marquise " printed.

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