AW: [Caml-list] Unix.waitpid

AW: [Caml-list] Unix.waitpid

[Bauer, Christoph]

Hi,

> 
> 
> Well, using the corresponding C-API-function,
> you should better rename your arguments:
> 
>   wpid is the pid you wait for (the argument to Unix.waitpid)  and
>    pid is the value you get from that function:
> 
> 
> ===== from the wait(2)/waitpid(2)-manpage =============
>      pid_t
>      waitpid(pid_t wpid, int *status, int options);
> =======================================================
> 

Ok.

> 
> BTW: where do you set the "pid" initially?
> 

>From a Unix.create_process call.

> And: if waitpid returns with a pid, then you can't wait on this
> pid/process again. So, if you wait for one pid and get a different
> pid as result of the function call, then you wait again.
> But if you another time waits for a pid, which you alread caught
> (got as a result once before), then you can wait infinite,
> because that pid was caught by waitpud before... and you have to
> wait until the pid is reused by the kernel or wait until next 
> reboot. ;-)

Ok, then I'll use pid = 0 (or wpid = 0, after the renaming) to terminate
the loop. 

Thanks for the replies,
Christoph Bauer

AW: [Caml-list] Unix.waitpid

[Bauer, Christoph]

Sorry,

> let wait ?(delay_time = 0.01) pid idle x =
>   let rec wait' () =
>     idle x;
>     delay delay_time;
>     let pid = try fst (Unix.waitpid [Unix.WNOHANG] pid) with 
> _  -> 1 in
>       if pid <> 0 then wait' ()
>   in wait' ()
this code is wrong, my original code was:

let rec wait' () =
      idle x;
      delay delay_time;
     let wpid = try fst( Unix.waitpid [Unix.WNOHANG] pid) with _ -> pid in
       if pid <> wpid then wait' ()
    in wait' ()

Christoph Bauer