Once again I repeat my recommendation for Time::Piece. It's also worth noting that of all the Date/Time modules, this is the one that is most likely to make it into the core distribution (it was going to be in 5.8, but was removed at the last minute).

I should also point out this section from the documentation for Date::Manip

SHOULD I USE DATE::MANIP

If you look in CPAN, you'll find that there are a number of Date and 
Time packages. Is Date::Manip the one you should be using? In my 
opinion, the answer is no most of the time. This sounds odd coming 
from the author of the software, but read on.

Date::Manip is written entirely in perl. It's the most powerful of the
date modules. It's also the biggest and slowest.
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For this reason, I avoid Date::Manip most of the time.

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

At any rate, Date::Manip (does not require compilation) appears to cover all of the contingencies in your problem. From the Date::Manip docs:

  4.  The amount of time between two dates.

      $date1=&ParseDate($string1);
      $date2=&ParseDate($string2);
      $delta=&DateCalc($date1,$date2,\$err);
          => 0:0:WK:DD:HH:MM:SS   the weeks, days, hours, minutes,
                                  and seconds between the two
      $delta=&DateCalc($date1,$date2,\$err,1);
          => YY:MM:WK:DD:HH:MM:SS  the years, months, etc. between
                                   the two
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In the interests of being specific, how exactly is this not meeting your needs?

Cheers,
Matt

I think ar0n already gave you the best answer here when you first asked it.

coreolyn (not looking for a flame war -- It's just the right answer)

And I thought I gave you the 2nd best answer here with the Date::Manip solution. To get into more detail:

use Date::Manip;
# This would give you h:m:s difference
Delta_Format(DateCalc($day1, $day2), 2, '%hh h:%mv m:%sv s');
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If you could post a concrete example of what you are looking for, or what has been wrong with the solutions offered to you, that would make it easier for us to help you.

$ cat datediff.pl 
#!/usr/bin/perl -w
use strict;
use Time::JulianDay;
use vars qw/ $opt_a $opt_b /;
use Getopt::Std;

my $dateA = "59:59:23:31:11:2002"; # 1 second before 2003
my $dateB = "00:00:00:01:00:2003"; # 2003

getopt( "a:b:");
if( $opt_a ) { $dateA = $opt_a; }
if( $opt_b ) { $dateB = $opt_b; }

print "dateA = $dateA\n";
print "dateB = $dateB\n";

my ($sec,$min,$hours,$mday,$month_0_to_11,$year)  = split /:/, $dateA;
print "($sec,$min,$hours,$mday,$month_0_to_11,$year)\n";
### ssA is the seconds since JAN 1st 1970 for dateA
my $ssA = jd_timelocal($sec,$min,$hours,$mday,$month_0_to_11,$year);
print "seconds from Jan 1st 1970 to 1 second before 2003 = $ssA\n";


($sec,$min,$hours,$mday,$month_0_to_11,$year)  = split /:/, $dateB;
print "($sec,$min,$hours,$mday,$month_0_to_11,$year)\n";
### ssB is the seconds since JAN 1st 1970 for dateB
my $ssB = jd_timelocal($sec,$min,$hours,$mday,$month_0_to_11,$year);
print "number of seconds from Jan 1st 1970 to midnight 2003 = $ssB\n";

my $diff = $ssB - $ssA;

print "The diffence in seconds between $dateB and $dateA = $diff\n";
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$ ./datediff.pl 
dateA = 59:59:23:31:11:2002
dateB = 00:00:00:01:00:2003
(59,59,23,31,11,2002)
number of seconds from Jan 1st 1970 to 1 second before 2003 = 10414079
+99
(00,00,00,01,00,2003)
number of seconds from Jan 1st 1970 to midnight 2003 = 1041408000
The diffence in seconds between 00:00:00:01:00:2003 and 59:59:23:31:11
+:2002 = 1
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