Is the C99 preprocessor Turing complete?

Question

After discovering the Boost preprocessor\'s capabilities I found myself wondering: Is the C99 preprocessor Turing complete?

If not, what does it lack to not qualify?

Answer 1

It's Turing complete within limits (as are all computers since they don't have infinite RAM). Check out the kinds of things you can do with Boost Preprocessor.

Edit in response to question edits:

The main limitation on Boost is the maximum macro expansion depth which is compiler-specific. Also, the macros that implement recursion (FOR..., ENUM..., etc.) aren't truly recursive, they just appear that way thanks to a bunch of near-identical macros. In the big picture, this limitation is no different than having a maximum stack size in an actually recursive language.

The only two things that are really necessary for limited Turing-completeness (Turing-compatibility?) are iteration/recursion (equivalent constructs) and conditional branching.