Check if perl script is already running (Win32)

use Win32::Mutex;
my ($name) = ( $0 =~ /(.*)\.pl/ );
$name =~ s/^(.*\\)//;    # erase full path names, they give problems creating mutexes
($name) = ( $^X =~ /(.*)\.exe/ ) if ( $name eq '' ); # Compatibility for perl2exe
my $mutex;
Win32::Mutex::Create( $mutex, 0, $name );
if (Win32::GetLastError) {
  # mutex already exists - another instance of this script is running
  exit;
}