The start of this new year started with some buzz about a leap second being introduced between Dec 31st 2008, 23:59:59 and Jan 1st 2009, 00:00:00. I've had people ask where this leap second actually comes from, and whether you need to worry about it in your applications. To understand leap seconds means, unfortunately, understanding how time is actually kept.

He ponints out one of the major problems - how time is kept. With variants of Universal Time, it makes it hard to track down what's "right". He breaks out the difference between other time storage methods and the unix time that PHP can use (that counts the number of seconds since Jan 1st 1970) and how the leap second was handled for each.

Bug report #35958 must have the most obscure one ever:

"strftime usually returns a string from the number of seconds since 1 jan 1970. Now, it lags and returns a string representing 23 seconds too late."

If you know what's going on though, it isn't really that weird.

He talks about the leap seconds that have been added to keep things straight, and how that's affecting PHP's built-in date/time functionality. He also shows an example of how you can get the "more correct" time versus the normal output...]]> Wed, 11 Jan 2006 06:41:13 -0600