I've written a program which combines MFC UI and open source code
which is based on stdio calls. It used to be that the stdio calls
e.g.

fprintf(stderr, "There were %d frames encoded", frames);

wouldn't do anything - they'd compile fine and execute without
problems. Though I have no idea what an MFC program considers
"stderr"? It just seemed to be going into the bit bucket. Recently
I've done some serious code overhaul including making a bunch of the
files into a library which gets linked in. Now every time I hit one
of these stderr outputs I get an exception. It's a good way to find
them and comment them out but I'm wondering why it just recently
STARTED doing this?