<?php
// File name:	timezone.inc.php
// Description:	PHP subroutines to deal with time zone information
// Date:	2004-04-05
// Author:	imacat <imacat@pristine.com.tw>
// Copyright:	Copyright (C) 2004-2007 Pristine Communications

// timezone_iso: Return the timezone in ISO 8601 format
function timezone_iso()
{
    // Cache the result
    static $cache;
    // Return the cache
    if (isset($cache)) {
        return $cache;
    }
    
    // Calculate the time zone string
    $tzsec = date("Z");
    $tzsign = ($tzsec >= 0? "+": "-");
    $tzsec = abs($tzsec);
    $tzmin = floor($tzsec / 60);
    $tzsec = $tzsec % 60;
    $tzhr = floor($tzmin / 60);
    $tzmin = $tzmin % 60;
    $tz = sprintf("%s%02d:%02d", $tzsign, $tzhr, $tzmin);
    // Cache it
    $cache = $tz;
    return $tz;
}

?>