[AccessD] Don't miss this special occasion... (Unix/Posix time)

Hi Charlotte

John wrote UTC time zone. But if you prefer, insert your own timezone bias:

<code>
Public Function DateFromUnix( _
  ByVal dblSeconds As Double, _
  Optional lngLocalTimeBias As Long) _
  As Date
  
' Converts UNIX (or POSIX) time value to UTC date value.
' Optionally, a local time bias can be specified;
' this must be in minutes with a resolution of 15 minutes.
'
' Examples:
'   UTC. dblSeconds: 1000000000, lngLocalTimeBias: 0
'     2001-09-09 01:46:40
'   CET. dblSeconds: 1000000000, lngLocalTimeBias: -60
'     2001-09-09 02:46:40
'
' 2004-03-23. Cactus Data ApS. CPH.
' 2008-02-27. Constants renamed for clarity.
  
  ' UNIX epoch (start time).
  Const cdatUnixEpoch       As Date = #1/1/1970#
  ' Maximum time bias in seconds, 12 hours.
  Const clngSecondsBiasMax  As Long = 12& * 60&
  ' Count of seconds of one day.
  Const clngSecondsPerDay   As Long = 24& * 60& * 60&
  
  Dim dblDays               As Double
  Dim dblDaysSeconds        As Double
  Dim lngSeconds            As Long
  Dim datTime               As Date
  
  ' Limit intervals for DateAdd to Long to be acceptable.
  dblDays = Int(dblSeconds / clngSecondsPerDay)
  dblDaysSeconds = dblDays * clngSecondsPerDay
  lngSeconds = dblSeconds - dblDaysSeconds
  
  datTime = DateAdd("d", dblDays, cdatUnixEpoch)
  datTime = DateAdd("s", lngSeconds, datTime)
  If lngLocalTimeBias <> 0 Then
    If Abs(lngLocalTimeBias) < clngSecondsBiasMax Then
      datTime = DateAdd("n", -lngLocalTimeBias, datTime)
    End If
  End If
  
  DateFromUnix = datTime

End Function

Public Function UnixTimeValue( _
  ByVal datTime As Date, _
  Optional ByVal lngLocalTimeBias As Long) _
  As Double
  
' Converts UTC date value to UNIX (or POSIX) time value.
' Optionally, a local time bias can be specified;
' this must be in minutes with a resolution of 15 minutes.
'
' Examples:
'   UTC. datTime: #09/09/2001 01:46:40#, lngLocalTimeBias: 0
'     1000000000
'   CET. datTime: #09/09/2001 02:46:40#, lngLocalTimeBias: -60
'     1000000000
'
' 2004-03-23. Cactus Data ApS. CPH.
' 2008-02-27. Constants renamed for clarity.
  
  ' UNIX epoch (start time).
  Const cdatUnixEpoch       As Date = #1/1/1970#
  ' Maximum time bias in seconds, 12 hours.
  Const clngSecondsBiasMax  As Long = 12& * 60&
  
  Dim dblSeconds            As Double
  
  If lngLocalTimeBias <> 0 Then
    If Abs(lngLocalTimeBias) < clngSecondsBiasMax Then
      datTime = DateAdd("n", lngLocalTimeBias, datTime)
    End If
  End If
  dblSeconds = DateDiff("s", cdatUnixEpoch, datTime)
  
  UnixTimeValue = dblSeconds

End Function
</code>

Have fun!

/gustav
>>> cfoust at infostatsystems.com 13-02-2009 19:08 >>>
Is that Pacific or Eastern?

Charlotte Foust 

-----Original Message-----
From: accessd-bounces at databaseadvisors.com 
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of jwcolby
Sent: Friday, February 13, 2009 10:04 AM
To: Access Developers discussion and problem solving
Subject: [AccessD] Don't miss this special occasion...

There is something that is important happening today! And I just know
how interested you are in this bit of time trivia for all you IT geeks
out there ...

Many computer operating systems measure time by counting the number of
seconds before/after midnight of January 1, 1970. This is known as POSIX
or Universal Time Code (UTC) time.

Today, a memorable event occurs in UTC time.
On Friday, Feb 13 2009 at exactly 3:31:30 PM the UTC will be 1234567890
- the numbers of seconds since 1/1/70.
--
John W. Colby
www.ColbyConsulting.com