DateTime::Format::Epoch::MacOS is a Perl module that can convert DateTimes to/from Mac OS epoch seconds.

SYNOPSIS

use DateTime::Format::Epoch::MacOS;

my $dt = DateTime::Format::Epoch::MacOS->parse_datetime( 1051488000 );
DateTime::Format::Epoch::MacOS->format_datetime($dt);
# 1051488000

my $formatter = DateTime::Format::Epoch::MacOS->new();

my $dt2 = $formatter->parse_datetime( 1051488000 );

$formatter->format_datetime($dt2);
# 1051488000

This module can convert a DateTime object (or any object that can be converted to a DateTime object) to the number of seconds since the Mac OS epoch.
Note that the Mac OS epoch is defined in the local time zone. This means that these two pieces of code will print the same number of seconds, even though they represent two datetimes 6 hours apart:

$dt = DateTime->new( year => 2003, month => 5, day => 2,
time_zone => Europe/Amsterdam );
print $formatter->format_datetime($dt);

$dt = DateTime->new( year => 2003, month => 5, day => 2,
time_zone => America/Chicago );
print $formatter->format_datetime($dt);

Mac OS X is a Unix system, and uses the Unix epoch (1970-01-01T00:00:00). Use DateTime::Format::Epoch::Unix instead.