The PHP gettimeofday() function returns the current time.

The PHP gmdate() function formats a GMT/UTC date and time, and returns the formatted date string.

The PHP gmmktime() function returns the Unix timestamp for a GMT date.

The PHP gmstrftime() function formats a GMT/UTC time and/or date according to locale settings.

The PHP idate() function formats a local time and/or date as integer.

The PHP localtime() function returns the local time.

The PHP microtime() function returns the current Unix timestamp with microseconds.

The PHP mktime() function returns the Unix timestamp for a date.

The PHP strftime() function formats a local time and/or date according to locale settings.

The PHP strptime() function parses a time/date generated with strftime().

The PHP strtotime() function parses an English textual datetime into a Unix timestamp (the number of seconds since January 1 1970 00:00:00 GMT).

The PHP time() function returns the current time in the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT).

The PHP timezone_abbreviations_list() returns an associative array containing dst, offset, and the timezone name.

The PHP timezone_identifiers_list() returns an indexed array containing all timezone identifiers.

The PHP timezone_location_get() returns location information for the given timezone.

The PHP timezone_name_from_abbr() returns the timezone name from abbreviation.

The PHP timezone_name_get() returns the name of the timezone.

The PHP timezone_offset_get() returns the timezone offset from GMT.

The PHP timezone_open() creates a new DateTimeZone object.

The PHP timezone_transitions_get() returns all transitions for the timezone.