c-macro-expansionc-macro-expansion is a compiled Lisp function in `
cmacexp.el'. (c-macro-expansion START END CPPCOMMAND &optional DISPLAY) Run a preprocessor on region and return the output as a string. Expand the region between START and END in the current buffer using the shell command CPPCOMMAND (e.g. "/lib/cpp -C -DDEBUG"). Be sure to use a -C (don't strip comments) or equivalent option. Optional arg DISPLAY non-nil means show messages in the echo area.