--- a/cpp.rst	Sat Aug 01 22:32:58 2009 +0300
+++ b/cpp.rst	Fri Aug 07 20:36:28 2009 +0300
@@ -10,3 +10,25 @@
 
   $ cl /E <file>.c
 
+* Who to see predefined macros?
+
+See
+
+  http://predef.sourceforge.net/
+  http://en.wikipedia.org/wiki/C_preprocessor#Compiler-specific_predefined_macros
+
+** GNU C Compiler.
+
+  $ gcc -dM -E - < /dev/null
+
+** HP-UX ansi C compiler.
+
+  $ cc -v EMPTY.c
+
+** SCO OpenServer C compiler.
+
+  $ cc -## EMPTY.c
+
+** Sun Studio C/C++ compiler.
+
+  $ cc -## EMPTY.c