use MCE::Simple -strict, max_workers => 4;

MCE::Simple->init(
    # mce options
    user_begin => sub {
        MCE->say("hello from ", MCE->wid);
    },
    # spawn options
    on_finish => sub {
        my ( $pid, $exit, $ident, $signal, $error, @ret ) = @_;
        say "@_";
    },
);

mce_foreach my $i ( 1..10 ) {
    MCE->say(MCE->wid, ": $i * 2 = ", $i * 2);
}

spawn "Hello", sub { "one" };
spawn "There", sub { "two" };

foreach my $ident (qw/foo baz/) {
    spawn $ident, sub {
        my $text = "something from $$";
    };
}

sync;

# clear or set options
MCE::Simple->init();

sub fib {
    my $n = shift;
    return $n if $n < 2;

    spawn my $x = fib($n - 1);
    spawn my $y = fib($n - 2);

    sync $x;
    sync $y;
 
    return $x + $y;
}

say "fib(20) = ", fib(20);


##</code><code>##

$ perl demo.pl 
hello from 1
hello from 2
hello from 3
hello from 4
3: 2 * 2 = 4
4: 1 * 2 = 2
2: 3 * 2 = 6
3: 5 * 2 = 10
4: 6 * 2 = 12
1: 4 * 2 = 8
4: 7 * 2 = 14
3: 8 * 2 = 16
2: 9 * 2 = 18
1: 10 * 2 = 20
10792 0 Hello 0  one
10793 0 There 0  two
10794 0 foo 0  something from 10794
10795 0 baz 0  something from 10795
fib(20) = 6765

##</code><code>##

use MCE::Simple -strict, max_workers => 16;

use MCE::Semaphore;
use Time::HiRes 'time';

my $start = time;
my $sem = MCE::Semaphore->new(8);

mce_foreach_s ( 1 .. 1_000_000 ) {
    $sem->down;
    $sem->up;
}

printf "%0.3f seconds\n", time - $start;

##</code><code>##

mce_foreach_f ("/path/to/file") {
    MCE->print($_);
}

# what about file handles? no problem...
open my $fh, "<", "/tmp/infile.txt" or die "open error: $!";

mce_foreach_f my $line ( $fh ) {
    MCE->print($line);
}

close $fh;