Why not just use the C preprocessor? If you have C code, you should probably have one lying around on your system.

EDIT: I missed the part about not wanting to expand macros in code. Try something like this: 

$ perl -pe 'y/A-Za-z/N-ZA-Mn-za-m/ unless /^\s*#/' < INPUT | cpp - | \
    perl -pe 'y/A-Za-z/N-ZA-Mn-za-m/ unless /^\s*#/ > OUTPUT'

[download]
That should hide the macros in code from CPP unless you choose really weird names.

In reply to Re: C code pre-processor by educated_foo
in thread C code pre-processor by dgsmith_50

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