Thanks very much Richard and Jochen. It dawned on me yesterday afternoon while taking a walk (which is how I solve most of my programming problems) that I needed libc - not GNU GCC sources. Just now before checking in here I managed to download libc in tarball format. Now I need to see if I have an app to extract tarballs. I much appreciate your help! Thanks very much!

Fine to heat that you got some kind of success. To post a link just copy it to the clipboard, insert in the CP editor, and wait a short time. It will be inserted as link with the title of the page as pre-selected link text (so it can be edited).

I've studied up on the issue enough to have convinced myself that any further effort to use any system capabilities to determine the count of bytes previously written to an IStream would be fruitless. While Microsoft's documentation does push the analogy that IStreams are pretty much like files, the fact is that the analogy only goes so far. It appears that some file capabilities don't exist for IStreams in compound storage, and I'd guess at this point marking the end of written bytes is one of them. It follows from this that there is nothing akin to a SetEndOfFile(). It occurs to me that these missing capabilities could be coded into an app that uses compound document files, for example creating a seperate IStream to store the actual length of data written into other IStreams.