Given this script:

#!perl -w

use strict;
use Date::Calc qw/Localtime Delta_DHMS Delta_YMDHMS/;

my $now = time();
my $total = 63072000;  # approx 2 years

doit( $now, $now + $total );
doit( $now - $total, $now );

sub doit
{
   my ( $start, $end ) = @_;
   my @ts1 = (Localtime( $start ))[0..5];
   my @ts2 = (Localtime( $end   ))[0..5];

   my ($years, $months, $days, $hours, $mins, $secs) =
      Delta_YMDHMS(@ts1, @ts2);

   print "$years years, $months months, $days days, $hours hours, $min
+s minutes\n";
}
[download]

I get the following output:
2 years, 0 months, 0 days, 0 hours, 0 minutes
2 years, 0 months, -1 days, 0 hours, 0 minutes

I really expected those two lines to be the same.

If I use the Delta_DHMS function, and remove all references to $years and $months, then the output is the same.

The documentation for Delta_YMDHMS promises that roll-over from the time difference is correctly applied to the delta-day, but I wonder if it's actually working.

Could someone please tell me what I'm doing wrong?

Thanks,
-Dave