How can I make a macro time out?

What is the best way to make a macro time out?
I have a macro that will be used globally but don't want them to be able to use it forever. I wrote in some code that times out the macro based on the system date. Unfortunately, in other countries they set their system clock formats differently so my code doesn't work on their pc's. What's a good way to do this?

[shelbym]

Rick I am working on a macro and would like to do the same thing. Maybe the all knowing Alex can help us out. Thanks,

Shelby

Alex can never be stumped

[Alex]

Well, here is a small piece of code which will not work after, say, Jan 1, 2006:

Sub MyMacro()
    If Date > DateSerial(2006, 1, 1) Then
        MsgBox "Sorry, this function expired", vbCritical
        Exit Sub
    End If
    ' Do something
End Sub

As you can see, you can use the function Date to return the current system date and DateSerial to construct a date by specifying the year, month, and day number.

You can do a lot of interesting things with dates. For example, you can subtract two dates to determine the difference in days between them. You can use this in your macro too:

Sub MyMacro2()
    Dim Expiry As Date
    Expiry = DateSerial(2005, 1, 1)
    If Date > Expiry Then
        MsgBox "Sorry, this function expired " & (Date - Expiry) & " days ago", vbCritical
        Exit Sub
    End If
    ' Do something
End Sub

will this code work if they have european time? example: 2005/02/07
i would like for this to work globally.

[Alex]

Yes, the "Date" data type is locale invariant. However when you print the date, it will appear differently on different locales. Or if you use the "#" notation to represent a date, such as in:

Sub DateExample()
    Dim d As Date
    d = #2/7/2005#
    MsgBox Format$(d, "mmmm d, yyyy")
End Sub

Then this notation is locale-aware and could mean either February 7th, or July 2nd, depending on your OS settings. However I intentionally used the DateSerial function which is always predictable.

[shelbym]

My concern was if the user changes there system date back a few days they could easily fool the expire date. So here is what I come up with:

If IsNull(ActiveDocument.Properties("GraniteFills", 1)) = True Then
    ActiveDocument.Properties("GraniteFills", 1) = Date
ElseIf ActiveDocument.Properties("GraniteFills", 1) < Date Then
    ActiveDocument.Properties("GraniteFills", 1) = Date
End If

Dim Expiry As Date
    Expiry = DateSerial(2005, 2, 9)
    If ActiveDocument.Properties("GraniteFills", 1) > Expiry Then
        MsgBox "Your copy of the Granite Fills program expired " & (ActiveDocument.Properties("GraniteFills", 1) - Expiry) & " days ago.", vbCritical, "Granite Fills"
        Exit Sub
    End If

I know there are still ways around this, but is adds one more level of security.

Thanks,

Shelby