File Date/Time and Time Zones

[webnetworks]

Hi,

We have a huge problem and can not find any information on this on the TechNet and MSDN site of Microsoft.

When we look up the creation date/time from a file, it returns a specific time, e.g. 15:05. But when the time zone changes, the time is changed to 16:05. This all happens on the server running Windows NT4.0 SP6a, file opened from a DOS box. Since we want the original date and time this is not what we want to see, we use this as a sort of copy protection.

But wait, there's more. When we do the same from a mapped network drive on a Windows 2000 Pro station with the same time zone and locale settings, we get 18:05 as the file creation time!!! And to make it even worse, from a Windows 98 SE with the same time zone and locale settings we get 17:05 as the file creation time!!!
But when we use a NET USE TIME \\server command all times are changed again, while are times where equal to the servers time. From all stations the time is set to 16:05, just like on the server.

Now this has become a complete blur. When we set the correct time zones (and we checked dates and times from the time zone information) file times differ from OS to OS and are synced when we sync the time to the servers time.

HOW COME!!!!! AAAAAARRRRRRGGGGGHHHHHHH!!!!!


Jeroen.

[John G Duffy]

From the way I gather it, The files data and times are stored in GMT time and the retrieving systems GMT offset comes into play here.
There are more than several API's that deal with file Date and Times. Here are several I know of

option Explicit

private Type FILETIME
dwLowDateTime as Long
dwHighDateTime as Long
End Type

private Type SYSTEMTIME
wYear as Integer
wMonth as Integer
wDayOfWeek as Integer
wDay as Integer
wHour as Integer
wMinute as Integer
wSecond as Integer
wMilliseconds as Integer
End Type

Dim hfile as Integer
Dim FileStruct as OFSTRUCT
Dim iRC as Integer
Dim CreationTime as FILETIME
Dim LastAccessTime as FILETIME
Dim LastWriteTime as FILETIME
Dim SYSTIME as SYSTEMTIME
Dim LocalTime as FILETIME
Dim s$, dl&

private Declare Function FileTimeToLocalFileTime& Lib "kernel32" _
(lpFileTime as FILETIME, lpLocalFileTime as FILETIME)
private Declare Function GetTimeFormat& Lib "kernel32" Alias "GetTimeFormatA" _
(byval Locale as Long, byval dwFlags as Long, lpTime as SYSTEMTIME, _
byval lpFormat as Long, byval lpTimeStr as string, byval cchTime as Long)
private Declare Function FileTimeToSystemTime Lib "kernel32" _
(lpFileTime as FILETIME, lpSystemTime as SYSTEMTIME) as Long
private Declare Function GetFileTime Lib "kernel32" (byval _
hfile as Long, lpCreationTime as FILETIME, lpLastAccessTime _
as FILETIME, lpLastWriteTime as FILETIME) as Long
private Declare Function OpenFile Lib "kernel32" (byval lpFileName as _
string, lpReOpenBuff as OFSTRUCT, byval wStyle as Long) as Long
private Declare Function hread Lib "kernel32" Alias "_hread" _
(byval hfile as Long, lpBuffer as Any, byval lBytes as Long) as Long
private Declare Function lclose Lib "kernel32" Alias "_lclose" (byval _
hfile as Long) as Long

' Also from another sample I have
#If Win32 then

private Declare Function GetTimeFormat& Lib "kernel32" Alias "GetTimeFormatA" (byval Locale as Long, byval dwFlags as Long, lpTime as SYSTEMTIME, byval lpFormat as Long, byval lpTimeStr as string, byval cchTime as Long)
private Declare Function GetDateFormat& Lib "kernel32" Alias "GetDateFormatA" (byval Locale as Long, byval dwFlags as Long, lpTime as SYSTEMTIME, byval lpFormat as Long, byval lpTimeStr as string, byval cchTime as Long)
private Declare Function FileTimeToSystemTime& Lib "kernel32" (lpFileTime as FILETIME, lpSystemTime as SYSTEMTIME)
private Declare Function GetFileInformationByHandle& Lib "kernel32" (byval hFile as Long, lpFileInformation as BY_HANDLE_FILE_INFORMATION)
private Declare Function CloseHandle& Lib "kernel32" (byval hObject as Long)

#End If 'WIN32







'
I suppose all are documented on MSDN.Microsoft.com
If you are interested in a couple of samples, Send me a private message with your E-Mail address and I will send them to you. They are to large to post here


John G

[webnetworks]

This goes beyond the local workstations:
- Each file saved on the server gets the time from the local workstation
- One hour is added (!!!) instead of subtracted to get the GMT time, this is done by either the workstation or the server
- The file is stored on the server
- When the file is retrieved again one hour is added to the file date/time

Now please explain this behaviour. We've tested this on three independent servers running Windows NT 4.0 SP6a.

Due to this behaviour the GMT time set on the file is also incorrect, even when checking using API's...


Jeroen.

[joedamato]

I know this is long ago, but I did run into the same problem now!! Did you manage to find a solution for it????

[dglienna]

It's posted. Are you running NT and Windows 98 like the original poster was (and which has already helped quite a few people)

If you have the *exact* same problem, then we'll help, otherwise, start your own thread, please.

(Doesn't sound like a VB6 problem anyways)