Multiple Users Concurrently Editing Processing Tables

[Bob Stockler]

Mark Luljak wrote (on Sun, Jun 19, 2005 at 10:05:43PM -0400):

| On Sun, Jun 19, 2005 at 09:44:05PM -0400, Bob Stockler may or may not have
| proven themselves an utter git by pronouncing:
| > A thread on the filePro Mailing List the other day encouraged
| > me to write a filePro Processing Table that could substitute
| > for the "Define Processing" choice on the filePro Main Menu.
| > 
| > It permits but one user at a time to edit a processing table,
| > writing a lockfile of it's own to prevent such.
| > 
| > If a user editing a table exits inappropritely, or doesn't exit,
| > the lockfile remains.
| > 
| > If on UNIX/Linux, or on Windows and filePro v5.0.13 or later,
| > the name of the user LOCKing it is shown as editing it if
| > another user trys to edit it.
| 
| Key words:  "filePro processing table"
| 
| How'd you handle the possibility of a race condition without flock() or
| fcntl() access via the fP language?
| 
| Granted, in 99% of the contexts in which it would be used, nobody's going
| to notice, and it shouldn't fail if you did only what you stated you
| did.  I'm just wondering what you did to account for the possibility (if
| anything), as this is something I wouldn't think would be suited at all to
| fP table coding in order to be -100%- foolproof.
| 
| Not knocking it, just curious about the details.

It's not 100% foolproof, but certainly better than having multiple
simultaneous users of naked dcabe.

In the first place, the number of filePro programmers is probably
not huge, and the likelyhood of two of them attempting to edit the
same table at the nearly exact same time is probably quite small.

What this prevents is one user editing a table and not saving it
before leaving for lunch, taking a nap or whatever, and then later
someone else trying to edit that table.  UNIX/Linux users would
know the user name of the one who had the table open, as would
Windows users having filePro 5.0.13 or later.

Bob

-- 
Bob Stockler - bob at trebor.iglou.com - http://members.iglou.com/trebor
Author: MENU EDIT II - The BEST Creator/Editor/Manager for filePro User Menus.
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