> Provided the writing and the reading use the same choice of interface
> (which primarily means, on the one hand, read() and write(), and on the
> other, mmap()), you shouldn't need to do any explicit syncs.  (You need
> to take care when mixing read/write and mmapped access, but not when
> all accesses use the same choice of interface.)
> 
> At least that's how I've always understood it, and that's been my
> experience.  I've been bitten occasionally by missing synchronization
> between users of different interfaces, but never otherwise.

The only case that really does cause problems is if one process is
using NFS to acess the files.  This can cause extreme grief!
The grief is compounded by NFS implementations that compare client
and server times.

	David

-- 
David Laight: david@l8s.co.uk