php displays wrong date in php for 31-12-9999

Question

When I try to execute following statement in PHP

echo gmdate("M d Y H:i:s", gmmktime(0, 0, 0,12, 31, 9999));

PHP returns following date

Result Jan 01 1970 00:00:00

I also did try using following strtotime function but the result is same

echo gmdate("M d Y H:i:s", strtotime('2999-12-31'));

Result: Jan 01 1970 00:00:00

Any idea what could be wrong here?

Answer 1

The years 9999 and 2999 are out of range for UNIX timestamps (the format returned by strtotime() and gmmktime()). The maximum valid value is INT_MAX, 0x7fffffff (around January 18th, 2038).

Answer 2

The max date the gmdate function can use is 19 Jan. 2038; trying to use a date beyond that just doesn't compute (literally), so PHP returns the base Unix date that you're seeing in your result.

See http://us2.php.net/manual/en/function.gmdate.php.