Identical to the date() function except that the time returned is Greenwich Mean Time (GMT). For example, when run in Finland (GMT +0200), the first line below prints "Jan 01 1998 00:00:00", while the second prints "Dec 31 1997 22:00:00".
Note: Prior to PHP 5.1.0, negative timestamps (dates before 1970) didn't work on some systems (Windows, for example).
See also date(), mktime(), gmmktime() and strftime().