I have a number of legacy Clipper 5.2E DBFCDX RDD application programs
linked "plain vanilla style" with Rtlink. No non-5.2E modules are
used. It isn't feasible to replace them all at the same time. I would
like to use Visual FoxPro 7 to replace these applications over time.
This would involve simultaneous access to some Clipper 5.2E DBFCDX RDD
data files by both the legacy Clipper 5.2E programs and the new Visual
FoxPro 7 programs. I have prototyped this, and I find that the Visual
FoxPro 7 programs do not appear to sense the Clipper 5.2E record
locks. Am I missing something either in Clipper 5.2E or Visual FoxPro
7 that would resolve this? Or, is there a workaround? I am familiar
with Apollo, so I don't think that I need any additional information
about this. I would prefer to work within native Visual FoxPro 7 to
solve the problem.

As a Clipper/SIx and Delphi/Apollo programmer, but with no experience
of Visual Foxpro, I can only answer the question indirectly. DBFCDX
and Apollo provide support up and including Foxpro 2.0. This is
several years earlier than Visual Foxpro 7.0. I doubt wether you will
get compatible locks from your VFP 7.0 and Clipper Apps. If I was in
your position, I would down-grade the tables (.dbf's) back to FoxPro
2.0 (which one would think would be supported by VFP 7.0) in
order to ensure all-round compatibility, not just in locking.