[h-e-w] Re: Temp files in the temp directory

[Peter Kaiser]

Jason Rumney wrote:

> > Where is it documented that when NT emacs reads, alters, and writes a 
> > file in the %TEMP% directory -- say, on Win2K -- it doesn't create a 
> > backup file?
> Emacs does not create backup files for simply reading a file. It does
> create autosave files after the file is altered (though not
> immediately), and it creates backup files when a file is saved. There is
> no special treatment for %TEMP%.

What you describe is what I'd expect.  However, I've monitored emacs's behavior using the 
Sysinternals file monitoring utility FILEMON, and in %TEMP% emacs doesn't do this.

With NT emacs I read, modify, and save a file.  FILEMON shows that emacs normally renames the 
original file to its backup name, then writes the modified buffer under the original name.

But in %TEMP% -- and only there, so far as I can tell -- it goes through this sequence for the 
modified file instead:

    1. Open
    2. Query writability
    3. Close
    4. Open
    5. Set information
    6. Write (under the original name)
    7. Flush
    8. Close

No rename, no backup file -- in other words, different logic.  And that's what I'm asking about.  I 
have the monitoring logs.

Pete