Restrict one download at a time (PHP)

[forum11]

I using PHP script (using headers) to download file (after logging in users can download files).

Is there a way to restrict users to download one file at a time?
Means if user already downloading a file and he clicks on second file the download does not start and user get a message that one download is already in progress.

Thanks

[Dan Grossman]

This is a restriction you're going to need to impose at a higher level, not after the request is processed and passed off to the PHP interpreter.

http://dominia.org/djao/limitipconn.html