PID lockfile

[Aahz]

In article <87iqlwvemo.fsf at benfinney.id.au>,
Ben Finney  <bignose+hates-spam at benfinney.id.au> wrote:
>
>In the case of the ‘lockfile’ library, Skip is aiming for a
>cross-platform solution, with atomic behaviour; he has implemented
>lock acquisition with a ‘link’ operation on Unix, and a ‘mkdir’
>operation on Windows.
>
>But both of those, of course, create a new file. What I want is to
>lock an existing file. Is ‘lockf’ particularly prone to cross-platform
>troubles on Unix variants? (Since the “become a daemon” pattern
>makes no sense on anything but Unix, I'm only concerned with PID file
>behaviour that works on Unix.)

IIUC, you must use something like Skip's trick to work correctly with
NFS.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

"At Resolver we've found it useful to short-circuit any doubt and just
refer to comments in code as 'lies'. :-)"
--Michael Foord paraphrases Christian Muirhead on python-dev, 2009-3-22