The NearSpace client application is a viewer for read-only databases. It's normally a separate record database that's viewed, but it can be a resource database, and can be itself, the executing program. We've never had a "chunk underlocked" problem.
The system calls involved in an execution where the application reads from itself are basically these:
1) DmOpenDatabase(), after which both the system and the executing application have DmOpenRefs to the database. Mode is dmModeReadOnly.
2) A few calls to DmNumResources() and DmResourceInfo(), hopefully not relevant to the current discussion.
3) N successive calls MemHandleLock(DmGetResourceIndex(...)) for the last N (typically 10-20) resources in the database.
4) Interact with the user for a long time, accessing database contents only through the memory pointers acquired in step 3.
5) On each of those N pointers to resource data, do:
MemHandle h = MemPtrRecoverHandle(rsrcPtr);
MemPtrUnlock(rsrcPtr);
DmReleaseResource(h);6) DmCloseDatabase().
Greg Lutz NearSpace, Inc.
[...]
> > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Behalf Of Jeff > > Diamond > > Sent: Tuesday, March 25, 2003 12:01 PM > > To: Palm Developer Forum > > Subject: Opening the current App database causing crash on exit.. > > > > > > I have a program that reads data from a PRC database. It works fine > > when that PRC database is external to itself. > > But when I try to open and read from my current (running) PRC, > > everything works fine until I exit. I then get a fatal memory manager > > error saying only "Chunk Underlocked, but with no additional info". > > > > In debugging this with the debug console, it appears that my App has > > fully exited by this point, and the error is in the system. > > Interestingly enough, it MAKES NO DIFFERENCE in my app if I choose to > > not close the database at all before exiting, or even if I close it twice! > > > > I assume there is some logical issue with the fact that I've opened my > > App for reading, and so has the OS. > > Is there a way to make this work? > > > > Thoughts much appreciated! > > - Jeff Diamond
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