Posted by William Gill on 05/04/06 17:56

I have a PHP user form that I supply a serial number for response
tracking. The serial number is kept in a simple text file
(tracknum.dat). When someone submits the form, PHP reads the number,
increments it, writes the new number to the file, and sends the number
back to the user for tracking purposes. To prevent two users from
getting the same serial number I put a delay loop in the script using
while(file_exists(tracknum.lock). tracknum.lock is created before
tracknum.dat is opened, and deleted after the new serial number is
written. This seems to work, but it could cause an infinite loop if for
some reason the lock file doesn't get deleted by the previous user. Am I
being paranoid about the possible infinite loop? Is there a smarter way
to do this?

Thanks

Bill

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