fork() and wiatpid() quirk on RHEL AS 4 and PERL version 5.8.5

nkx has asked for the wisdom of the Perl Monks concerning the following question:

This works fine when run interactively but hangs with a bunch of defunct children when the same user schedules an AT job to run the same script. Has anyone encountered this issue with fork() on RHEL AS 4?

#!/usr/bin/perl
Е..
my @children = ();
ЕЕ
sub mysub {
my $pid = fork();
if ($pid) {
push(@children, $pid);
}
if( $pid == 0 ){
# child process code here
exit 0;
}
}
ЕЕ
foreach (@children) {
waitpid($_, 0);
}
[download]

Comment on fork() and wiatpid() quirk on RHEL AS 4 and PERL version 5.8.5 Download Code

Replies are listed 'Best First'.
Re: fork() and wiatpid() quirk on RHEL AS 4 and PERL version 5.8.5 by jeffa (Bishop) on Jan 15, 2009 at 18:41 UTC
How much time passes between the moment one of your child processes exits and when it is reaped? If they are not reaped in a timely manner, they will fill up the process table with defunct zombies. Have you tried this instead: `$SIG{CHLD} = sub { wait() }` [download] jeffa L-LL-L--L-LL-L--L-LL-L-- -R--R-RR-R--R-RR-R--R-RR B--B--B--B--B--B--B--B-- H---H---H---H---H---H--- (the triplet paradiddle with high-hat)	[reply] [d/l]
Re^2: fork() and wiatpid() quirk on RHEL AS 4 and PERL version 5.8.5 by JavaFan (Canon) on Jan 15, 2009 at 18:48 UTC
Or even: `$SIG{CHLD} = 'IGNORE'; # Children are automatically reaped.` [download]	[reply] [d/l]
Re^3: fork() and wiatpid() quirk on RHEL AS 4 and PERL version 5.8.5 by nkx (Initiate) on Jan 15, 2009 at 19:44 UTC
Thanks for your advice. I will test this and report the result.	[reply]
Re^3: fork() and wiatpid() quirk on RHEL AS 4 and PERL version 5.8.5 by nkx (Initiate) on Jan 21, 2009 at 18:06 UTC
Your advice was spot on and resolved the issue. Thank you!	[reply]