php man page for dateinterval

DATEINTERVAL(3) 							 1							   DATEINTERVAL(3)

The DateInterval class

INTRODUCTION
	Represents a date interval.

	A  date  interval  stores  either  a fixed amount of time (in years, months, days, hours etc) or a relative time string in the format that
       DateTime's constructor supports.

CLASS SYNOPSIS
       DateInterval

       DateInterval

       Properties

       o public integer$y

       o public integer$m

       o public integer$d

       o public integer$h

       o public integer$i

       o public integer$s

       o public integer$invert

       o public mixed$days

       Methods

       o public DateInterval::__construct (string  $interval_spec)

       o publicstatic DateInterval DateInterval::createFromDateString (string  $time)

       o public string DateInterval::format (string  $format)

PROPERTIES
	      o $y
		- Number of years.

	      o $m
		- Number of months.

	      o $d
		- Number of days.

	      o $h
		- Number of hours.

	      o $i
		- Number of minutes.

	      o $s
		- Number of seconds.

	      o $invert
		- Is 1 if the interval represents a negative time period and 0 otherwise. See DateInterval::format.

	      o $days
		- If the DateInterval object was created by DateTime.diff(3), then this is the total number of days  between  the  start  and  end
		dates.	Otherwise, $days will be FALSE.  Before PHP 5.4.20/5.5.4 instead of FALSE you will receive -99999 upon accessing the prop-
		erty.

PHP Documentation Group 													   DATEINTERVAL(3)