It's not exactly simple, but here's how to do it the old-fashioned way with pipe, sysread, and syswrite. Note how the pipe protocol uses the number of bytes transferred in every message to detect its length:

use strict;

my @array = ();

pipe my $read, my $write or
    die "Cannot open pipe";

for(1..3) {
    defined(my $pid = fork) or die "Can't fork\n";

    if($pid) {
        next;  # Parent: continue loop
    }

        # Child
    pipe_send($write, "I'm process $$!");
    exit 0;
}

# Parent
for(1..3) {
    my $element = pipe_recv($read);
    push @array, $element;
}

print "array = @array\n";

##################################################
sub pipe_send {
##################################################
    my($fh, $message) = @_;

    my $bytes = sprintf "0x%08x", length($message);
    syswrite($fh, $bytes . $message);
}

##################################################
sub pipe_recv {
##################################################
    my($fh) = @_;

    die "Protocol corrupted" if
        sysread($fh, my $bytes, 10) != 10;
    $bytes = hex($bytes);

    my $data = "";
    while($bytes != 0) {
        my $read = sysread($fh, my $chunk, $bytes);
        last unless defined $read;
        $bytes -= $read; $data .= $chunk;
    }
    return $data;
}
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