Posted by Bob_M (remove X for email) on 05/05/06 01:51

On Thu, 04 May 2006 14:56:30 GMT, William Gill <noreply@gcgroup.net>
wrote:

>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
Why not try "flock"ing the file(s). YOUR process will wait for the
other (owner) task to release it before continuing.

B

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