Re: Rename atomicity

[Mike Castle]

On Tue, Mar 06, 2001 at 05:51:45PM +0100, Assar Westerlund wrote:
> Mike Castle <address@hidden> writes:
> > NT.  (NT will happily rename() across disks, hardly an atomic operation).
> 
> What rename() is that?  It's not the one in their posix library I
> assume?  Is there a rename function in any of the ordinary set of libraries.

Well, I was mostly considering the rename() function supplied with vendor
libraries.  Ie, Borland and MS products.  I would suppose that autoconf
would attempt to support those products as well.  As far as the Cygwin
stuff goes, I would have to defer to others.  Otherwise I'd have to search
the source.

> > Some earlier implementations of Linux.
> 
> Any version that is still in use?

I appears I may be mistaken about this, or it's of limited consequence.  It
may appear to be limited to situations where a the rename target involves a
symlink in the path.  And at least the kernel affected is 2.2.12, so yes.
Still in use.  To be honest though, I'm in the middle of moving and my
brain is fried.  Someone else should do the same google search of "linux
atomic rename" and read the appopriate results.

> > I believe some implementations of Solaris (for performance reasons, rename
> > was not made atomic).
> 
> Could you give pointers to the information on which renames() aren't
> atomic on what versions of Linux and Solaris?

Damned if I can find the Solaris pointer I was looking for again.  Perhaps
I was hallucinating.  Sorry.  (I did try to find the citation before I made
the initial post but couldn't.  And I still can't.  Maybe I dreamt it.  A
sure sign of spending too much time in front of the computer is when you
start dreaming in text.)

> Derek: what did you want this for?  CVS?  And have you escaped on
> vacation yet? :-)

Considering the RCS atomic rename() comment earlier, I was wondering what
the issue was as well.

mrc
-- 
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