note 14203 added to function.localtime.php

The corresponding function call to get the GMT time is not specified here. Only local time is reported, according to the current TZ environment setting. One could try to use putenv() to set another timezone temporarily, however when running PHP in safe mode, putenv() is disabled and cannot be used in scripts. However it's possible to simulate gmttime() by using localtime() and by transforming the results in the returned array. The biggest problem with this function is that it is using an OS-dependent and localtime() function which is also depending on the standard C library implementation (some of them, do not support accurate locales). The second problem is that localtime() does not return an index specifying the local timezone offset, so transforming this date to UTC will become very ugly. Some systems support the gmtime() C function call, some don't. To get the timezone, some C libraries provide a global _timezone variable, some provide it as a macro that use a function call, some do not provide any variable, and one must deduce it by interpreting the TZ environment. This is too much ugly for PHP. PHP should be extended by adding support to gmttime() with the same parameters, but the returned array should include additional indices to store the timezone offsets in seconds and names for both standard time and DST, for example: [tz_offset_std] = 3600, [tz_offset_dst]= 7200, [tz_name_std] = 'CET', (GMT+01:00) [tz_name_dst] = 'CEDT'. (GMT+02:00) Or for the international, locale-independant, Zulu time (also known as UCT or simply UT), returned by gmtime(): [tz_offset] = 0, [tz_offset_dst]= 0, [tz_name] = 'Z', [tz_name_dst] = 'Z'. But it's much easier to use PHP's date() and gmdate() to make such transformations. Beware of DST rules! In the southern hemisphere, standard time still occurs during winter, but the southern Winter is in June, not in December ! Use the tm_isdst indicator to know which timezone to display or interpret ! http://www.php.net/manual/en/function.localtime.php