The Citrix Administrator has the ability to limit each user from running any particular application more than once. You don't have to do it (and I'm not sure you could, programmatically). It's in the Citrix Server Management console, under Application Limits: a checkbox for "Allow only one instance of application for each user".

Hank Fay

>I have an executable application that is run concurrently by multiple users on a Citrix server. My own knowledge of Citrix is zilch. I have been asked to determine if any given user attempts to run muliple - simultaneous - instances of the application (and if so, prevent that from happening).
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>I visualize some kind of system call that somehow identifies the user id within Citrix, so that if that user id is already active, I don't allow the app to execute. Can anyone tell me if such a system call exists? (I'm already aware of the Foxpro SYS call that tells me the user id within a desktop, but it seems to me that wouldn't work inside a Citrix environment. Is that correct?)
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>TIA
>Howie