dbrlock() in Clipper hangs

["Peter B. Steiger" <wypbs_002@bornagain.com>]

Since there are other Clipper users on this list, maybe you can help me
with a strange problem I have running a very large (EXE > 4MB)
application.  When it starts up, the login routine attempts to lock the
user's record to update the last login date and time, but when it gets
to the dbrlock() function, the application hangs - no error message, and
I can still alt-C to terminate, but something is going into an infinite
loop.  Since I don't know the internal mechanism used by dbrlock() I
can't even guess what it is trying (and failing) to do.

The strange thing is, smaller applications which use dbrlock() have no
trouble at all.  So I'm thinking it might have something to do with the
way the large app uses DPMI or UMB or both.  It is Clipper 5.2e linked
with Blinker 6.0.  Later in the program are some C and assembler
functions for accessing the volume serial number of the C drive, but
those are not used before the dbrlock() freezes up.

What kind of debugging flags would be useful to track this down?  If I
turn them all on, the debug log reaches several meg by the time it gets
to that login prompt.

Kernel is 2.4.23, gcc is 3.2.2, dosemu is 1.1.99.1.  I'm still using
that instead of 1.2.0 because 1.2.0 gives me errors reading global.conf,
but that's a subject for a separate message!  Oh, and the DOS version is
Win98; I have a boot directory linked to the actual C: partition with my
real Win98 files.

-------
Peter B. Steiger
Cheyenne, WY