use Apache::SubProcess;
defined (my $kid = fork) or die "Cannot fork: $!\n";
if ($kid) {
    # Parent runs this block
}
else {
    # Child runs this block
    $r->cleanup_for_exec(); # untie the socket
    chdir '/' or die "Can't chdir to /: $!";
    close STDIN;
    close STDOUT;
    close STDERR;
  
    # some code goes here

    CORE::exit(0);
}
# possibly more code here usually run by the parent