use strict;
use POSIX ":sys_wait_h";

while (1) {
    for(1..10) {spawn(\&foo)}          # fork off 10 &foo()'s
    my $s = sleep (2);                 # $s will hold the number of seconds actually slept

    # clean up our children
    1 while ((my $child = waitpid(-1, WNOHANG)) > 0);

    print "---";
    if ($s) { print "Slept for $s seconds\n"; }# If we slept at all
    else    { print "Did not sleep at all\n"; }# If we didn't
}

sub spawn {
    return if fork();                  # Fork and return the parent
    exit shift->();                    # exec the coderef passed as arg
}

sub foo {
    print "*" for (1..5);
}