File locking questions

[Bern Ertl]

If I write an app which runs on a network and handles files on a server, what happens if:

1) My app opens a sequential file LOCK WRITE

or

2) My app locks a range of records in a RANDOM file

and then a power failure or GPF or whatever zaps my app?

Will the files stay locked? How is this situation handled?

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Bernard Ertl

[This message has been edited by Bern Ertl (edited February 03, 2001).]

[Gary Stout]

Bern,

I believe that when the program terminates, the locking will
also cease. I have an app that uses random files and used in
a network environment and there have been cases where a record
didn't unlock (because of bugs or random features) and its
usually just a matter of exiting the program and going back
into it and all is well again.

HTH,
Gary Stout
[email protected]

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[This message has been edited by Gary Stout (edited February 03, 2001).]

[Bern Ertl]

Gary,

Do you mean by "when the program terminates" that the program goes through a normal close? I am wondering what happens when the terminal the app is running on gets zapped (power failure, GPF, whatever) and the program doesn't have the ability to terminate properly.



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Bernard Ertl

[Don Dickinson]

It has been my experience that when you GPF any files that were open remain open (locks in tact). Rebooting the workstation or clearing the workstation session or logging out and back in should close the files and clear the locks.
Best Regards,
Don

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www.basicguru.com/dickinson

[Don Dickinson]

I forgot to mention the power failure - if you have a power failure, I'd assume that the network will timeout your session in a while and clear your open files. On my novell 3.2 server this appears to take somewhere between 20 and 60 seconds. There are some good network people (Bud Durland, etc) that might have a more specific answer.
--Don

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www.basicguru.com/dickinson

[Bern Ertl]

Don,

I gather from your messages that the networking OS is handling the file locks then, and logging out/aborting (power failure) the network session will terminate all open files & locks? That would be super. I was wondering how one was supposed to recover if one app cannot unlock the locks from a different app. Thanks for the clarification.



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Bernard Ertl