Re: How to run the child process parellel to the parent process with fork

[bojinlund]

This shows two other alternatives of parallel processing (not explicitly using fork). Save this as MyChameleon.pm:

package MyChameleon;

use strict;
use warnings;
use threads;

$| = 1;    # autoflush STDOUT

my $used_as_script = not caller();

if ($used_as_script) {

    print "Start script\n";
    my $thread_to_do = threads->create( \&to_do, 'thread', 5 );
    my $thread_sys = threads->create(
        sub {
            system $^X, "-MMyChameleon", "-e", "MyChameleon::to_do('sy
+stem')";
        }
    );
    to_do( 'script', 3 );
    $thread_to_do->join;
    $thread_sys->join;
    exit;
}

sub to_do {
    my ( $tag, $times ) = @_;
    $times //= 10;
    print "$tag: Hello World!\n";
    map { print "$tag ($_)\n"; sleep 1 } ( 1 .. $times );
    print "$tag: is done\n";
}

!!1;

Run it like this: “perl MyChameleon.pm”.

See also How a script becomes a module