(PHP 5 >= 5.2.0, PHP 7) Returns new DateTime object

(PHP 4, PHP 5, PHP 7) Returns the day of the week

(PHP 5 >= 5.1.2, PHP 7) Returns an array with information about sunset/sunrise and twilight begin/end

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

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

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

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

(PHP 4, PHP 5, PHP 7) Convert Unix timestamp to Julian Day

(PHP 4, PHP 5, PHP 7) Get Unix timestamp for a GMT date

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