--- a/emacs.rst	Mon Nov 01 18:40:08 2010 +0200
+++ b/emacs.rst	Tue Nov 02 10:30:40 2010 +0200
@@ -279,3 +279,15 @@
 
   http://xslt-process.sourceforge.net/
                 home page
+
+* Useful program logging.
+
+Put first line to your log file, you must replace default-directory to dir where you build program:
+
+  -*- mode: compilation-minor; mode: auto-revert-tail; default-directory: "~/devel/proj" -*-
+
+Program must use one of supported by 'compilation-minor-mode' (see
+'compilation-error-regexp-alist'), like:
+
+  printf(__FILE__ ":%d: %s\n", __LINE__, msg);  /* msg - user defined string */
+