From: "Harrison, John R" <johnh@ichips.intel.com>
To: "Christopher Conway" <conway@cs.columbia.edu>
Cc: <caml-list@yquem.inria.fr>, "Harrison, John R" <johnh@ichips.intel.com>
Subject: RE: [Caml-list] Unix.system returns "no child processes"
Date: Fri, 9 Dec 2005 16:15:41 -0800 [thread overview]
Message-ID: <196F1D996F92CD46A542EA519DB8CE4702AD0289@orsmsx409> (raw)
Hi Chris,
| I am using Unix.system to invoke external commands from within Ocaml.
On
| the old machines (with the 32-bit version of Ocaml), I would
| occasionally get the exception Unix_error(ECHILD,"waitpid","") from
| Unix.system. With the new machines, I'm seeing this at every call to
| Unix.system, every time. I have investigate the behavior of the
| sub-processes, and they are terminating normally, with no indication
of
| any error.
I also sometimes see the intermittent error:
Exception: Unix.Unix_error (Unix.ECHILD, "waitpid", "").
But what I'm doing with the system call is sufficiently sleazy that I
probably deserve it. I'm running OCaml under the checkpointing program
"ckpt". The following function is supposed to make the session
checkpoint itself, then print a startup banner when execution is
resumed:
let self_destruct bannerstring =
let complete_banner =
if bannerstring = "" then startup_banner
else startup_banner^"\n "^bannerstring in
Gc.compact();
let pid = string_of_int(Unix.getpid()) in
(ignore(Unix.system("kill -USR1 "^pid));
Format.print_string complete_banner;
Format.print_newline(); Format.print_newline());;
Sometimes I get the exception above instead of the banner when the
process restarts. The likelihood of that happening seems highly
machine-dependent, and even on a given machine there's no obvious
pattern.
John.
next reply other threads:[~2005-12-10 0:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-10 0:15 Harrison, John R [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-12-09 19:35 Christopher Conway
2005-12-09 20:26 ` [Caml-list] " Olivier Andrieu
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