konversi tanggal ke unix time

Private Function ConvertToTglUnix(tgl As Date) As String
    ConvertToTglUnix = (tgl - DateSerial(1970, 1, 1)) * 86400
End Function
Private Function xtime(time As Date) As String
Dim the_date As Date
Dim system_time As SYSTEMTIME
Dim local_file_time As FILETIME
Dim utc_file_time As FILETIME

    ' Get the local time.
    the_date = CDate(time)

    ' Convert it into a SYSTEMTIME.
    DateToSystemTime the_date, system_time

    ' Convert it to a FILETIME.
    SystemTimeToFileTime system_time, local_file_time

    ' Convert it to a UTC time.
    LocalFileTimeToFileTime local_file_time, utc_file_time

    ' Convert it to a SYSTEMTIME.
    FileTimeToSystemTime utc_file_time, system_time

    ' Convert it to a Date.
    SystemTimeToDate system_time, the_date

    ' Display the result.
    xtime = Format$(the_date)
End Function

' Convert a Date into a SYSTEMTIME.
Private Sub DateToSystemTime(ByVal the_date As Date, ByRef system_time As SYSTEMTIME)
    With system_time
        .wYear = Year(the_date)
        .wMonth = Month(the_date)
        .wDay = Day(the_date)
        .wHour = Hour(the_date)
        .wMinute = Minute(the_date)
        .wSecond = Second(the_date)
    End With
End Sub
'Convert a SYSTEMTIME into a Date.
Private Sub SystemTimeToDate(system_time As SYSTEMTIME, ByRef the_date As Date)
    With system_time
        '' The following doesn't work internationally.
        'the_date = CDate( _
        '    Format$(.wMonth) & "/" & _
        '    Format$(.wDay) & "/" & _
        '    Format$(.wYear) & " " & _
        '    Format$(.wHour) & ":" & _
        '    Format$(.wMinute, "00") & ":" & _
        '    Format$(.wSecond, "00"))

        ' Thanks to Justin Starnes for the
        ' following internationalized version.
        the_date = DateSerial(.wYear, .wMonth, .wDay) + _
                   TimeSerial(.wHour, .wMinute, .wSecond)
    End With
End Sub