multiple instance on Unix

David Bolen db3l at
Thu Sep 30 19:44:16 CEST 2004

Mike Meyer <mwm at> writes:

> The (old) standard method for locking on Unix is to use a file. Open
> it in exclusive mode. Using<filename>, O_EXCL | O_RDONLY) (or
> O_WRONLY, or O_RDWR) should do the trick.

The oldest methods I tended to use still went the mkdir() route, since
that tends to be more reliable across NFS links (where the MKDIR
operation is still generally atomic, and doesn't involve NFS
machinations to support locking).  And if you're using a filesystem to
implement stuff like this you may not know if it's local or not.

-- David

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