Change 11987 by jhi@alpha on 2001/09/10 23:24:11
Subject: avoiding hoardes of zombies
From: Nicholas Clark <[EMAIL PROTECTED]>
Date: Mon, 10 Sep 2001 22:00:40 +0100
Message-ID: <[EMAIL PROTECTED]>
Affected files ...
... //depot/perl/pod/perlipc.pod#31 edit
Differences ...
==== //depot/perl/pod/perlipc.pod#31 (text) ====
Index: perl/pod/perlipc.pod
--- perl/pod/perlipc.pod.~1~ Mon Sep 10 17:30:06 2001
+++ perl/pod/perlipc.pod Mon Sep 10 17:30:06 2001
@@ -121,11 +121,15 @@
$SIG{CHLD} = \&REAPER;
# now do something that forks...
-or even the more elaborate:
+or better still:
use POSIX ":sys_wait_h";
sub REAPER {
my $child;
+ # If a second child dies while in the signal handler caused by the
+ # first death, we won't get another signal. So must loop here else
+ # we will leave the unreaped child as a zombie. And the next time
+ # two children die we get another zombie. And so on.
while (($child = waitpid(-1,WNOHANG)) > 0) {
$Kid_Status{$child} = $?;
}
@@ -724,10 +728,13 @@
my $waitedpid = 0;
my $paddr;
+ use POSIX ":sys_wait_h";
sub REAPER {
- $waitedpid = wait;
+ my $child;
+ while (($waitedpid = waitpid(-1,WNOHANG)) > 0) {
+ logmsg "reaped $waitedpid" . ($? ? " with exit $?" : '');
+ }
$SIG{CHLD} = \&REAPER; # loathe sysV
- logmsg "reaped $waitedpid" . ($? ? " with exit $?" : '');
}
$SIG{CHLD} = \&REAPER;
@@ -881,10 +888,13 @@
my $waitedpid;
+ use POSIX ":sys_wait_h";
sub REAPER {
- $waitedpid = wait;
+ my $child;
+ while (($waitedpid = waitpid(-1,WNOHANG)) > 0) {
+ logmsg "reaped $waitedpid" . ($? ? " with exit $?" : '');
+ }
$SIG{CHLD} = \&REAPER; # loathe sysV
- logmsg "reaped $waitedpid" . ($? ? " with exit $?" : '');
}
$SIG{CHLD} = \&REAPER;
End of Patch.
