if (check_date($year,$month,$day))

##</code><code>##

use strict;
use warnings;

use Date::Calc qw( check_date );

my ( $year, $month, $day ) = ( 2006, 1, 30 );

printf "[$year, $month, $day] %s a valid date\n",
    check_date( $year, $month, $day ) ? 'is' : 'is not';

( $year, $month, $day ) = ( 2006, 1, 32 );

printf "[$year, $month, $day] %s a valid date\n",
    check_date( $year, $month, $day ) ? 'is' : 'is not';

( $year, $month, $day ) = ( 2006, 2, 29 );

printf "[$year, $month, $day] %s a valid date\n",
    check_date( $year, $month, $day ) ? 'is' : 'is not';

##</code><code>##

[2006, 1, 30] is a valid date
[2006, 1, 32] is not a valid date
[2006, 2, 29] is not a valid date