When running a perl script on C program, I get GLOB(0x1a6a8830) as my output

Question

For one of my projects, we had to write a multi-threaded program in C. Everything seemed to be going well. The professor then gave us a perl script to run with our C code once we were finished. However, on the console where I run the script, whenever my program should be outputting(i think), I get GLOB(0x1a6a8830) all over the place. Here is the output.

GLOB(0x1a6a8830)

TRANS 995 -589398 987 154107 472 435291

GLOB(0x1a6a8830)

TRANS 397 -557927 559 798860 989 -240933

GLOB(0x1a6a8830)

TRANS 289 -368267 408 139828 419 842413 277 -598329 613 372608 285 508034 256 -896287

With the TRANS (then numbers) being an input that is being captured by my C program. Does anyone know what this GLOB is????

use strict;
use warnings;
use integer;

if (@ARGV < 1) {

print "Use: $0 <program> [<nthreads> [<naccounts> [<seed>]]]\n";
exit 1;
}

my($prgm, $thread, $accts, $seed) = @ARGV;

$thread ||= 10;
$accts ||= 1000;
$seed ||= 0;

srand($seed);

my $outfile = 'testout-'.$$;
my($c_in, $f_in, $c_out, $f_out);
pipe $f_in, $c_in;
pipe $c_out, $f_out;
my $pid = fork;

`if ($pid == 0) {
open STDIN, '<&', $f_in;
open STDOUT, '>&', $f_out;
close $c_in;
close $c_out;
close $f_in;
close $f_out;
exec $prgm, $thread, $accts, $outfile;
exit 1;
} else {
close $f_in;
close $f_out;
}

# make the pipes autoflush
select $c_in; $| = 1;
select $c_out; $| = 1;
 select STDOUT;

sub sr {
my $line = shift;
print "\e[33m$line\e[m\n";
print $c_in "$line\n";
my $resp = $c_out;
chomp $resp;
print "\e[32m$resp\e[m\n";
return $resp;
}

my $init_skip = 0;
for my $id (0..($accts/10 - 1)) {
my $line = 'TRANS';
$line .= ' '.($id*10 + $_).' 10000000' for 1..10;
sr $line;
$init_skip++;
}

    print "\e[35mWaiting for initial deposits to complete...\e[m\n";
   sleep 60;

for my $line (1..1000) {
my $line = "TRANS";
my $bal = 0;
my $len = int rand 8;
my %dups;
for (0..$len) {
    my $acct = 1 + int rand $accts;
    my $amt = 1_000_000 - int rand 2_000_000;
    next if $dups{$acct}++;
    $bal += -$amt;
    $line .= " $acct $amt";
}
my $acct = 1 + int rand $accts;
next if $dups{$acct};
$line .= " $acct $bal";
sr $line;
}

print "\e[35mWaiting for transactions to complete...\e[m\n";
sleep 60;

for my $id (1..$accts) {
sr "CHECK $id";
}

print "\e[33mEND\e[m\n";
print $c_in "END\n";
print "\e[35mWaiting for program to exit...\e[m\n";
wait;
no integer;
print "\e[35mChecking output file:\e[m\n";

open F, $outfile;
my $trcount = 0;
my $trtime = 0;
my $balcount = 0;
my $baltime = 0;
my $total = 0;
while (<F>) {
if ($init_skip-- > 0) {
    die "Bad (initial deposit) output line: $_" unless /^\d+ OK TIME/;
} elsif (/ (OK|ISF \d+) TIME (\d+)(\.\d+) (\d+)(\.\d+)/) {
    $trtime += ($4 - $2) + ($5 - $3);
    $trcount++;
} elsif (/^\d+ BAL (\d+) TIME (\d+)(\.\d+) (\d+)(\.\d+)/) {
    $total += $1;
    $baltime += ($4 - $2) + ($5 - $3);
    $balcount++;
} else {
    die "Bad output line: $_";
}
}
close F;

if ($balcount != $accts) {
print "ERR: There were $accts accounts but only $balcount balance queries\n";
}
print "Final balance of all $accts accounts is $total\n";
my $travg = $trtime / $trcount;
printf 'The %d transactions took %.2fs total, or an average of %.4fs each'."\n",
$trcount, $trtime, $travg;
my $balavg = $baltime / $balcount;
printf 'The %d balance checks took %.2fs total, or an average of %.4fs each'."\n",
$balcount, $baltime, $balavg;

That is the entire perl script

My program acts as a multithreaded bank server, and accepts the commands TRANS and CHECK

Answer 1

At first glance, I see two typos in the script posted. First is the ` at line 25. The second is the line

my $resp = $c_out;

That is assigning the file handle to $resp rather than reading from it. It should probably be like this:

my $resp = <$c_out>;