#! perl -slw
use strict;
use Fcntl qw[ :flock ];
$|=1;

if( $^O eq 'MSWin32' ) {
    {
        local $^W;
        require Win32::API::Prototype;
        Win32::API::Prototype->import( 'ApiLink' );
    }
    ApiLink( 'perl58', 'int win32_flock(int fd, int oper)' ) or die $^E;
    our $flock;
    *flock = *win32_flock = *win32_flock;

}

die 'Already running' unless flock( DATA, LOCK_EX );

sleep 10;

flock( DATA, LOCK_UN ) or die $!;

__DATA__
stuff