(PHP 5 >= 5.5.0, PHP 7) Adds an amount of days, months, years, hours, minutes and seconds

(PHP 5 >= 5.3.0, PHP 7) Returns the difference between two DateTime objects

(PHP 5 >= 5.3.0, PHP 7) Sets the date and time based on an Unix timestamp

(PHP 5 >= 5.5.0, PHP 7) Returns new DateTimeImmutable object

(PHP 5 >= 5.2.0, PHP 7) Returns the timezone offset from GMT

(PHP 5 >= 5.2.0, PHP 7) Returns a numerically indexed array containing all defined timezone identifiers

(PHP 4, PHP 5, PHP 7) Return current Unix timestamp

(PHP 5 >= 5.2.0, PHP 7) Alias of

(PHP 5 >= 5.2.0, PHP 7) Alters the timestamp

(PHP 5 >= 5.3.0, PHP 7) Sets up a DateInterval from the relative parts of the string