package Error;
use var qw/$ERROR_HANDLER/;
@ISA = qw/ EXPORTER /;
@EXPORT_OK = qw/ &Error /;

$ERROR_HANDLER = undef;  # Because I need to be sure

sub Error {
  if ( defined( $ERROR_HANDLER ) ) {
    $ERROR_HANDLER->($@);
  }
  else {
    print STDERR "@_\n";
  }
}