As Erik couldn't even remember why he used "DOC", I thought I'd try for something more meaningful.

In penance, here's a free gift:

Andy's Handy Hint for Debugging Preprocessor Problems:
Most compilers provide a facility to save the Preprocessor output to a file; with Keil C51, it's the PREPRINT command-line option.
Conventionally, this creates a file with a .i extension.

If you have unexplained errors, or suspect that your macros might not be quite working properly, I recommend that you should check this preprocessor listing!