Added or corrected Commentary sections

1 files changed, 13 insertions, 1 deletions

diff --git a/lisp/progmodes/cmacexp.el b/lisp/progmodes/cmacexp.el
index 144ac7ab56f..dd2c6df2c67 100644
--- a/lisp/progmodes/cmacexp.el
+++ b/lisp/progmodes/cmacexp.el
@@ -1,4 +1,4 @@
-;;; cmacexp.el --- C macro expansion
+;;; cmacexp.el --- C preprocessor macro expansion
 
 ;; Copyright (C) 1988 Free Software Foundation, Inc.
 
@@ -21,6 +21,18 @@
 ;; along with GNU Emacs; see the file COPYING.  If not, write to
 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 
+;;; Commentary:
+
+;; This package gives you the ability to run the C macro preprocessor
+;; on the current region, expanding macros within it.  This can be useful
+;; when you're not sure of the value or expansion of such macros and want
+;; to make sure they're doing what you think they're doing.
+;;
+;; This package supports the following option variables:
+;;
+;; c-macro-preprocessor --- program to be used for macro expansion.
+;; c-macro-options --- command-line options to pass it.
+
 ;;; Code:
 
 (defvar c-macro-preprocessor "/lib/cpp"