Update dev documentation to explicitly mention that #include <config.h> should not...

diff --git a/doc/dev/style.md b/doc/dev/style.md
index 89a6b506a46b0ae3a8dc8f63d04aafc65de6497c..b3a7d26a0ed679a29bf51568e3ea69725f48da1c 100644 (file)
--- a/doc/dev/style.md
+++ b/doc/dev/style.md
@@ -125,6 +125,10 @@ The following lint and lint-like comments should be used where appropriate:
 should prevent multiple inclusion.  The OS is assumed to prevent multiple
 inclusion of its .h files.
 
+The `#pragma once` directive should be used instead of `#ifdef/#define`
+combo, and the `#include <config.h>` should not be used anywhere, the
+build system ensures that it's the first included file.
+
 A header file defining a public interface is generally placed in the source
 tree two levels below the C file that implements the interface.  For
 example, the include file defining the interface for `lib/dns/zone.c` is in
@@ -155,8 +159,7 @@ or for public files that do not declare any functions.
         * file, You can obtain one at http://mozilla.org/MPL/2.0/.
          */
     
-        #ifndef ISC_WHATEVER_H
-        #define ISC_WHATEVER_H 1
+        #pragma once
     
         /*****
          ***** Module Info