Re: Locking files for CLASH_DETECTION now supported on MS-Windows

[Paul Eggert <eggert@cs.ucla.edu>]

On 02/25/13 10:41, Eli Zaretskii wrote:
> If MS-Windows creates the lock file first, then the Posix host will
> see that it's a regular file and skip it.

Yes, that's one worrisome scenario -- if an MS-Windows
Emacs locks a file, POSIXish Emacs instances will ignore
the locks and won't be able to set locks themselves.

Two thoughts.  First, how about if the MS-Windows code
tries to use a symbolic link, and if this works then great,
otherwise it falls back on a regular file.  That way,
MS-Windows users who have the Create Symbolic Links right
will interoperate better with POSIXish Emacs.  (Perhaps
the MS-Windows code can try to directly determine whether
it has the Create Symbolic Links right; or perhaps it can
just try 'symlink' and inspect the resulting errno.)

Second, even if an MS-Windows user doesn't have a Create Symbolic
Links right, Emacs should still respect a symlink that happens
to be there, right?  Because the symlink could be placed there
by a POSIXish Emacs.  Does that part work correctly now on
MS-Windows?