echo mktime(2,0,0,4,-6,2004); /* or 0 to -5 */

This returns 1080176400 (2004-03-25 02:00:00) here (PHP 4.3.6) which
looks ok to me.

What are the values on your system?

ok I have some problems with test values here now, but I can provide the
original phpgw code
that is affected and the values from it:

$sday = mktime(2,0,0,$month,$day - ($weekday - 1),$year);
echo ':' . $day . ':' . $weekday . "<br />\n";
echo ':' . $year . '/' . $month . '/' . ($day - ($weekday - 1)) . ' : ' .
$sday . ":<br /><hr />\n";

Output values here 32bit linux machine:

:1:4
:2004/4/-2 : 1080518400:
:1:2
:2004/6/0 : 1085961600:
:1:6
:2004/05/-4 : 1082937600:
:1:6
:2004/05/-4 : 1082937600:

output values 64 bit itanium2:

:1:4
:2004/4/-2 : 1080694800:
:1:2
:2004/6/0 : 1085965200:
:1:6
:2004/05/-4 : 1083286800:
:1:6
:2004/05/-4 : 1083286800:

The complete function within this code was found is:

	function get_weekday_start($year,$month,$day)
	{
		$weekday = $this->day_of_week($year,$month,$day);

switch($GLOBALS['phpgw_info']['user']['preferences']['calendar']['weekdaysta
rts'])
{
// Saturday is for arabic support
case 'Saturday':
$this->days = Array(
0 => 'Sat',
1 => 'Sun',
2 => 'Mon',
3 => 'Tue',
4 => 'Wed',
5 => 'Thu',
6 => 'Fri'
);
switch($weekday)
{
case 0:
$sday =
mktime(2,0,0,$month,$day - 1,$year);
break;
case 6:
$sday =
mktime(2,0,0,$month,$day,$year);
break;
default:
$sday =
mktime(2,0,0,$month,$day - ($weekday + 1),$year);
break;
}
break;
case 'Monday':
$this->days = Array(
0 => 'Mon',
1 => 'Tue',
2 => 'Wed',
3 => 'Thu',
4 => 'Fri',
5 => 'Sat',
6 => 'Sun'
);
switch($weekday)
{
case 0:
$sday =
mktime(2,0,0,$month,$day - 6,$year);
break;
case 1:
$sday =
mktime(2,0,0,$month,$day,$year);
break;
default:
$sday =
mktime(2,0,0,$month,$day - ($weekday - 1),$year);
echo ':' . $day . ':' . $weekday . "<br />\n";
echo ':' . $year . '/' . $month . '/' . ($day - ($weekday - 1)) . ' : ' .
$sday . ":<br /><hr />\n";
break;
}
break;
case 'Sunday':
default:
$this->days = Array(
0 => 'Sun',
1 => 'Mon',
2 => 'Tue',
3 => 'Wed',
4 => 'Thu',
5 => 'Fri',
6 => 'Sat'
);
$sday = mktime(2,0,0,$month,$day -
$weekday,$year);
break;
}
return $sday - 7200;
}

after I changed this code by the following patch, it works as expected on
both platforms:

Index: class.datetime.inc.php

RCS file: /cvsroot/phpgwapi/phpgwapi/inc/class.datetime.inc.php,v
retrieving revision 1.5.2.12.2.8
diff -u -r1.5.2.12.2.8 class.datetime.inc.php
--- class.datetime.inc.php 1 May 2004 09:32:26 -0000 1.5.2.12.2.8
+++ class.datetime.inc.php 5 May 2004 11:41:19 -0000
@@ -216,15 +216,45 @@
);
switch($weekday)
{

•   				case 0:
  

•   					$sday =
  

mktime(2,0,0,$month,$day - 1,$year);

•   					break;
    				case 6:
  

•   					$sday =
  

mktime(2,0,0,$month,$day,$year);
break;

•   				default:
  

•   					$sday =
  

mktime(2,0,0,$month,$day - ($weekday + 1),$year);

•   				case 0:
  

•   				        if ($day == 1)
  

•   				        {
  

•   				         	if ($month
  

== 1)

•   				        	{
  

--$year;

$month = 12;

•   				         	}
  

•   				         	else
  

•   				         	{
  

--$month;

•   				         	}
  

•   				         	$day =
  

$this->days_in_month($month,$year);

•   				        }
  

•   				        else
  

•   				        {
  

•   				        	--$day;
  

•   				        }
    					break;
  

•   				default:
  

•   				        if ($day <=
  

($weekday + 1))

•   				        {
  

•   				         	if ($month
  

== 1)

•   				        	{
  

--$year;

$month = 12;

•   				         	}
  

•   				         	else
  

•   				         	{
  

--$month;

•   				         	}
  

•   				         	$day =
  

$this->days_in_month($month,$year) - $weekday;

•   				        }
  

•   				        else
  

•   				        {
  

•   				        	$day -=
  

($weekday + 1);

•   				        }
    			}
    			break;
    		case 'Monday':
  

@@ -239,15 +269,45 @@
);
switch($weekday)
{

•   				case 0:
  

•   					$sday =
  

mktime(2,0,0,$month,$day - 6,$year);

•   					break;
    				case 1:
  

•   					$sday =
  

mktime(2,0,0,$month,$day,$year);
break;

•   				default:
  

•   					$sday =
  

mktime(2,0,0,$month,$day - ($weekday - 1),$year);

•   				case 0:
  

•   				        if ($day <= 6)
  

•   				        {
  

•   				         	if ($month
  

== 1)

•   				        	{
  

--$year;

$month = 12;

•   				         	}
  

•   				         	else
  

•   				         	{
  

--$month;

•   				         	}
  

•   				         	$day =
  

$this->days_in_month($month,$year) + ($day - 6);

•   				        }
  

•   				        else
  

•   				        {
  

•   				        	$day -= 6;
  

•   				        }
    					break;
  

•   				default:
  

•   			        	if ($day <=
  

($weekday == 0) ? 6 : ($weekday-1))

•   			        	{
  

•   		         			if ($month
  

== 1)

•   		        			{
  

--$year;

$month = 12;

•   		         			}
  

•   		         			else
  

•   		         			{
  

--$month;

•   		         			}
  

•   		         			$day =
  

$this->days_in_month($month,$year) + ($day - (($weekday == 0) ? 6 :
($weekday-1)));

•   		       			}
  

•   		       			else
  

•   		      			{
  

•   		        			$day -=
  

($weekday-1);

•   		        		}
    			}
    			break;
    		case 'Sunday':
  

@@ -261,9 +321,25 @@
5 => 'Fri',
6 => 'Sat'
);

•   			$sday = mktime(2,0,0,$month,$day -
  

$weekday,$year);

•   			break;
  

•   		        if ($day <= $weekday)
  

•   		        {
  

•   		         	if ($month == 1)
  

•   		        	{
  

•   		          		--$year;
  

•   		          		$month = 12;
  

•   		         	}
  

•   		         	else
  

•   		         	{
  

•   		         		--$month;
  

•   		         	}
  

•   		         	$day =
  

$this->days_in_month($month,$year) + ($day - $weekday);

•   		        }
  

•   		        else
  

•   		        {
  

•   		        	$day -= $weekday;
  

•   		        }
    	}
  

•   	$sday = mktime(2,0,0,$month,$day,$year);
    	return $sday - 7200;
    }
  

any ideas?

Greetings and Thanks

Kai Hofmann