How to detect if a file is in use

[thomascd]

Hi is there a quick way too detect if a file is in use by any user ? (any kind of file, not foxpro tables)

 

[FoxEgg]

Use fopen.. it will return a negative number if file is in use....

JF

 

[Mike Gagnon]

thomascd

I guess it depends on the kind of file. Some files can be opened with FOPEN() some need to be open with the actual program they are associated with. But in most cases if you are trying to open a file that is already opened by another user VFP will throw an error that you can trap. Mike Gagnon

If you want to get the best response to a question, please check out FAQ184-2483 first.

 

[thomascd]

Thanks for your info

 

[SGLong]

Another way to find out if a file is in use is to try to rename it to itself, like:

RENAME myfile.dat TO myfile.dat

If VFP returns an error then the file is in use. I use this method when copying customer files from an FTP site by an automated process. Some files are rather large and my automated script runs every 15 minutes. If it can rename the file to itself, then the file is copied. If it can't, then it sleeps for 15 minutes and tries again.

Steve

 

[wgcs]

However, what if someone opens a file in the moment between checking if it's in use, and when you actually start trying to use it?

Better will be VFP8's TRY..CATCH error handling.