From Dan_Needles@ins.com

Hello,
  I'm trying to find out if there is an existing problem with defunct
processes using Open2() on Linux.

I have a loop that repeatively calls Open2() against a process that
takes a block of standard in, processes it and writes it to standard out

before the loop starts again. The output is always correct but the
called process remains in DEFUNCT state until I kill the Open2() calling

program. Worse, I cannot kill the DEFUNCT processes. Only by killing
the PERL program will they go away.

Any ideas? Do you know of any EMAIL LISTS that could address this?

Thanks,
Daniel L. Needles

From [Unknown Contact. See original ticket]

Did you close the file handles?
Did you wait on your forked children?

--tom

From [Unknown Contact. See original ticket]

Message RFC822:
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Message-ID: 38D45EEA.178B524F@ins.com
Date: Sat, 18 Mar 2000 21:00:26 -0800
From: "Daniel L. Needles" Dan_Needles@ins.com
Organization: International Network Services
X-Mailer: Mozilla 4.61 [en] (Win98; I)
X-Accept-Language: en
MIME-Version: 1.0
To: Tom Christiansen tchrist@chthon.perl.com
Subject: Re: [ID 20000318.005] Linix, Open2() and DEFUNCT processes.
References: 25181.953439599@chthon
Content-Type: text/plain; charset=us-ascii
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Tom Christiansen wrote:

Did you close the file handles?

Yes

Did you wait on your forked children?

Not sure. Could you check the 20 line program that follows:

#!/opt/CAV1perl/bin/perl
################################################################################

PROGRAM: OPEN2TEST Version 1.0 Daniel L.

Needles #
################################################################################

LOAD MODULES

use FileHandle; # For Open2 (Default PERL has no bidirectional pipes.)
use IPC::Open2; # For Open2 (Default PERL has no bidirectional pipes.)

PREPARE ENVIRONMENT

my $ip, $ms, $icmptype, $icmpcode, $responder, $junk;
my ($FIN, $FOUT) = (FileHandle->new, FileHandle->new);
open(DEBUG, '> async.out') or die "ASYNC: E: Could not open debug
file.\n";

while ( 1 ) {
$fping = open2( $FOUT, $FIN, "./f -e" ) || die "ASYNC: Could not open
bidirect
ional pipe.";

INPUT DATA

$wtcnt=0;
print $FIN "127.0.0.1\n";
print $FIN "127.0.0.1\n";
print $FIN "127.0.0.1\n";

SIGNAL TIME FOR OUTPUT

print $FIN "-\n";
close($FIN);

RECEIVE DATA

while ( $data = <$FOUT> ) {
if ($data ne "" ) {
( $ip, $ms, $icmptype, $icmpcode, $responder, $junk ) = split
/,/,$data,6;
chomp($responder);

}

}
close($FOUT);
sleep 60;
}

--tom

From [Unknown Contact. See original ticket]

Russ,
  Thanks! That was it! Adding waitpid($f, 0); after the last close did the trick!

Thanks,
Daniel L. Needles

"Daniel L. Needles" wrote​:

------------------------------------------------------------------------

Subject​: Re​: [ID 20000318.005] Linix, Open2() and DEFUNCT processes.
Date​: Sat, 18 Mar 2000 21​:00​:26 -0800
From​: "Daniel L. Needles" <Dan_Needles@​ins.com>
Organization​: International Network Services
To​: Tom Christiansen <tchrist@​chthon.perl.com>
References​: <25181.953439599@​chthon>

Tom Christiansen wrote​:

Did you close the file handles?

Yes

Did you wait on your forked children?

Not sure. Could you check the 20 line program that follows​:

#!/opt/CAV1perl/bin/perl
################################################################################

# PROGRAM​: OPEN2TEST Version 1.0 Daniel L.
Needles #
################################################################################

# LOAD MODULES
use FileHandle; # For Open2 (Default PERL has no bidirectional pipes.)
use IPC​::Open2; # For Open2 (Default PERL has no bidirectional pipes.)

# PREPARE ENVIRONMENT
my $ip, $ms, $icmptype, $icmpcode, $responder, $junk;
my ($FIN, $FOUT) = (FileHandle->new, FileHandle->new);
open(DEBUG, '> async.out') or die "ASYNC​: E​: Could not open debug
file.\n";

while ( 1 ) {
$fping = open2( $FOUT, $FIN, "./f -e" ) || die "ASYNC​: Could not open
bidirect
ional pipe.";

# INPUT DATA
$wtcnt=0;
print $FIN "127.0.0.1\n";
print $FIN "127.0.0.1\n";
print $FIN "127.0.0.1\n";
# SIGNAL TIME FOR OUTPUT
print $FIN "-\n";
close($FIN);

# RECEIVE DATA
while ( $data = <$FOUT> ) {
if ($data ne "" ) {
( $ip, $ms, $icmptype, $icmpcode, $responder, $junk ) = split
/,/,$data,6;
chomp($responder);

\}

}
close($FOUT);
sleep 60;
}

--tom