"Tom Zerucha" <[EMAIL PROTECTED]> wrote in message news:16578@palm-dev-forum...
> 1. Resource databases emerge from ExgDBWrite as a .prc image (which you
imply)
Yes. Rather it's a .prc or .pdb image (depending on whether the database
that went in was a record or resource database). The result is "essentially"
the same as a .prc or .pdb file on your desktop. There may be a few
inconsequential differences.
> 2. The database can determine the length only from the header
> information (which the documentation in the devzone says).
I'm not sure what you're getting at here. The last record or resource in a
.prc or .pdb file extends to the end of the file. If you take a valid .prc
or .pdb file and stick an extra byte on the end, the result will be a .prc
or .pdb file in which the last record or resource has an extra byte.
> And is Palm certifying the PRC/PDB format is and will be used by the
> ExgDB calls? This appears nowhere in any official documentation.
The .prc and .pdb format were intentionally NOT documented. Since it became
a defacto standard, we decided to go ahead and publish it. That doesn't mean
we're going to keep using this format for all eternity! But we're obviously
aware that changing the .prc/.pdb format would have serious consequences. As
for the ExgDB calls, we need to maintain the current behavior if we want
beaming apps to work between Palm devices. Again, we won't change it without
a good reason.
> Also note that if 1. is true, there may be some unpleasant sideeffects
> from taking the documentation too literally (e.g. if the TCP/IP
> stalls, you might not want to return a nonzero length, but if you
> don't return, the user can't send an event to cancel).
I think you want to return an error in this case. If you return "nothing
more to read" and you're in the last record or resource, the system will
just build a database with the last record or resource clipped.
--
Danny Epstein
OS Engineer, Palm Inc.
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