Re: Win32 rename()/unlink() questions

On Fri, 20 Sep 2002, Mike Mascari wrote:

> Bruce Momjian wrote:
> > Mike Mascari wrote:
> >
> >>Actually, looking at the pg_pwd code, you want to determine a
> >>way for:
> >>
> >>1. Process 1 opens "foo"
> >>2. Process 2 opens "foo"
> >>3. Process 1 creates "bar"
> >>4. Process 1 renames "bar" to "foo"
> >>5. Process 2 can continue to read data from the open file handle
> >>and get the original "foo" data.
> >
> >
> > Yep, that's it.
> >
>
> So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING)
> returns "Access Denied" when Process 1 attempts the rename. But
> I'm continuing to investigate the possibilities...

Does a sequence like
Process 1 opens "foo"
Process 2 opens "foo"
Process 1 creates "bar"
Process 1 renames "foo" to <something>
- where something is generated to not overlap an existing file
Process 1 renames "bar" to "foo"
Process 2 continues reading
let you do the replace and keep reading (at the penalty that
you've now got to have a way to know when to remove the
various <something>s)