Perl: Run multiple system commands at once - multithreading

Question

In perl, I have some code like
my $enter = `curl -s -m 10 http://URL`;
How would I use threading to run this function 10 times at once?
I found this but I am not sure how to use it to set a specific amount of threads
Edit: I guess I misunderstood what Threads::Queue was doing. My original question still stands for simultaneously running multiple commands at once.

Answer 1

You can use fork(). In this example, I use the Parallel::ForkManager module. $max_forks is the number of processes to run simultaneously (set to two for an example), and you'd put your system/curl code after ### add curl logic here, and remove the print() and sleep() example statements from there as well.
#!/usr/bin/perl
use warnings;
use strict;
use Parallel::ForkManager;
my $max_forks = 2;
my $fork = new Parallel::ForkManager($max_forks);
my #urls = (
'http://perlmonks.org',
'http://stackoverflow.com',
'http://slashdot.org',
'http://wired.com',
);
# on start callback
$fork->run_on_start(
sub {
my $pid = shift;
print "Starting PID $pid\n";
}
);
# on finish callback
$fork->run_on_finish(
sub {
my ( $pid, $exit, $ident, $signal, $core) = #_;
if ($core){
print "PID $pid core dumped.\n";
}
else {
print "PID $pid exited with exit code $exit " .
" and signal $signal\n";
}
}
);
# forking code
for my $url (#urls){
$fork->start and next;
### add curl logic here
print "$url\n";
sleep(2);
$fork->finish;
}
$fork->wait_all_children;