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OK, this is a similar question to this.

Actually I am trying to prevent people from multiple login into one single computer and use my application simultaneously.

This is because I want to stop them from buying one license, install it on a machine, and use certain remote desktop technologies to do multiple user login. I want to prevent them from violating the license agreement.

Is there anyway that I can do in my application for this? Or is multiple login simultaneously is simply not possible?

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Jeez, you're not helping yourself here you know; what computer, what OS, what application? any more detail at all purleeez. – Chopper3 Aug 17 '09 at 10:09
...and please use tags to show which OS and other relevant items. – John Gardeniers Aug 17 '09 at 12:08

If you want your application to 'break' any multi-user functionality on the computer its installed on, then good luck with that!. If you do succeed with this, please let me know the name of your app so I can add it to my 'Software to avoid at all costs' list.

If you want to limit usage, maybe you should be looking at making your application mutli-user and using a usb dongle to enforce the number of users/licenses.

However by implementing these measures, you are just creating reasons for people not to use your software.

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+1 for sure, doing this strikes me as interfering with the way your computer is supposed to work. And it might also interfere with other apps - everyone should always remember that their app is not the only one on a computer. – 21st Century Moose Aug 17 '09 at 10:34

This problem has to be taken care of at your application level, in your licensing code.

We use software specifically designed for use on a terminal server that counts exactly how many instances are running. In yesteryear it used to use a company called FlexLM however now they have a more modern method of tracking concurrent users.

I would highly suggest asking over at Stack Overflow on how to manage concurrent user licensing, how to search for multiple sessions, etc etc.

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One legitimate reason to limit simultaneous logins is to prevent a given user from opening multiple connections to your server and consuming unnecessary resources and licensing.

In Citrix there is a setting for doing this.

In other words, why would you want to allow a user to have multiple desktops open with a word processor on one, an e-mail client on another and a web browser on the third?

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You are right, but this should be controlled by the host operating system and not the app. – JS. Aug 17 '09 at 11:02
Are you saying user management should always be done through the OS? There are many flaws with that. – Keith Stokes Aug 17 '09 at 11:16
What im saying is that a word processor for example shouldnt control if and how users logon to the host system. – JS. Aug 17 '09 at 11:38

Is there anyway that I can do in my application for this?

That tells me you're looking at this from the point of view of a developer. As such I think you should take it over to Stack Overflow.

If you really want to know how to stop it at the application level you need to spend some time learning about the technologies involved. If you don't understand the platform you cannot control the application's use.

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A common tactic for one-instance programming is to open a port on the computer back to the program itself. If the program is already running, the port will be in use.

You'd probably have better responses over at Stack Overflow though.

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How crude! Ever hear of a mutex? – John Gardeniers Aug 18 '09 at 8:52
Honestly? No. This isn't SO! – Mark Henderson Aug 18 '09 at 9:05
I'm with Farseeker on this. I'm a sysadmin, not a programmer... Just something I've overheard in my travels – Garrett Aug 19 '09 at 17:44

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