Adding seconds to a date gets stuck when it reaches a leap second:
use DateTime; my $dt = DateTime->new( year => 1972, month => 12, day => 31, hour => 23, minute => 59, second => 55, time_zone => "UTC"); for(1..10) { $dt->add( seconds => 1); print $dt->datetime(), "\n"; } produces 1972-12-31T23:59:56 1972-12-31T23:59:57 1972-12-31T23:59:58 1972-12-31T23:59:59 1972-12-31T23:59:60 1972-12-31T23:59:60 1972-12-31T23:59:60 1972-12-31T23:59:60 1972-12-31T23:59:60 1972-12-31T23:59:60 -- Mike Mike Schilli [EMAIL PROTECTED]