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Anti Reserse Clock

I wanna ask how can I make anti reverse clock .
explaining.
I have written a demo application expire in specific date,
and I want to prevent program run again, if its expire and the user try to change back the date.

Do any one have good techniques, and what's the method to do that.
I know that any application change the system time send WM_TIMECHANGE to all top windows .
we can capure this message and detect if the system time has been changed.

first, how can I capture this meesage. if I use a background services capture this message. and is this technique usefull.
is there another techniques can I use ..?

Thanx.
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AAB
Asked:
AAB
1 Solution
 
jhanceCommented:
The most common technique is to keep a log of the run times of the application and see if you get a new run that is "older" than some prior run.  That way, you know that the clock has been messed with and you can refuse to run or do whatever you want.

I think that your WM_TIMECHANGE method is unreliable since:

1) Your app must be running all the time to catch this.
2) If the system clock is changed via the BIOS setup, you'll never see this change.
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null_pointerCommented:
I think the best thing to do will be to simply use the windows registry for this.
Make two entries as
First Access
Last access

Based on these two entries you can always check the no of days since last access and also no of days since the installation of your application.
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griesshCommented:
I think you forgot this question. I will ask Community Support to close it unless you finalize it within 7 days. Unless there is objection or further activity,  I will suggest to accept "jhance" comment(s) as an answer.

If you think your question was not answered at all, you can post a request in Community support (please include this link) to refund your points.
The link to the Community Support area is: http://www.experts-exchange.com/jsp/qList.jsp?ta=commspt

PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!
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Werner
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NetminderCommented:
Per recommendation comment force/accepted by

Netminder
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