From aac8fcb4b666c0357227725de28c1759841751f8 Mon Sep 17 00:00:00 2001
From: Gennaro Prota <gennaro.prota@gmail.com>
Date: Thu, 27 Jul 2006 10:27:37 +0000
Subject: [PATCH] boost guidelines (mainly from inspect tool: tabs, license
 reference text, etc.)

[SVN r34752]
---
 include/boost/implicit_cast.hpp | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/include/boost/implicit_cast.hpp b/include/boost/implicit_cast.hpp
index 2593cb4..27e1639 100755
--- a/include/boost/implicit_cast.hpp
+++ b/include/boost/implicit_cast.hpp
@@ -23,13 +23,22 @@ inline T implicit_cast (typename mpl::identity<T>::type x) {
 //template <typename T>
 //void implicit_cast (...);
 
-// Macro for when you need a constant expression (Gennaro Prota)
-#define BOOST_IMPLICIT_CAST(dst_type, expr)           \
-          ( sizeof( implicit_cast<dst_type>(expr) )   \
-                     ,                                \
-            static_cast<dst_type>(expr)               \
-          )
-
 } // namespace boost
 
+
+
+// Macro for when you need a constant expression.
+// Note that 'expr' is evaluated at most once, though
+// it appears three times (provided by Gennaro Prota; see
+// http://lists.boost.org/Archives/boost/2004/05/65687.php)
+//
+#define BOOST_IMPLICIT_CAST(dest_type, expr)                          \
+                   ( static_cast<dest_type>(                          \
+                      sizeof(boost::implicit_cast<dest_type>(expr)) ? \
+                                (expr) : (expr)                       \
+                      )                                               \
+                   )                                               /**/
+
+
+
 #endif // IMPLICIT_CAST_DWA200356_HPP