From 579269c39ed512217001f6b1e641ff4ad21fd6ee Mon Sep 17 00:00:00 2001
From: Fernando Cacciola <fernando.cacciola@gmail.com>
Date: Fri, 15 Aug 2003 21:27:29 +0000
Subject: [PATCH] New fix for std swap (for gcc >= 3.3)

[SVN r19624]
---
 include/boost/optional.hpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/boost/optional.hpp b/include/boost/optional.hpp
index ec4a209..04b72a1 100644
--- a/include/boost/optional.hpp
+++ b/include/boost/optional.hpp
@@ -271,9 +271,11 @@ bool operator != ( optional<T> const& x, optional<T> const& y )
 //
 namespace optional_detail {
 
-#ifdef __GNUC__
+// GCC <= 3.2 gets the using declaration at namespace scope (FLC)
+#if BOOST_WORKAROUND(__GNUC__, <= 3) && __GNUC_MINOR__ <= 2
    // workaround for GCC (JM):
    using std::swap;
+#define BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE
 #endif
 
 // optional's swap:
@@ -296,13 +298,17 @@ void optional_swap ( optional<T>& x, optional<T>& y )
   }
   else if ( !!x && !!y )
   {
-#ifndef __GNUC__
+// GCC > 3.2 and all other compilers have the using declaration at function scope (FLC)
+#ifndef BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE
+    // allow for Koenig lookup
     using std::swap ;
 #endif
     swap(*x,*y);
   }
 }
 
+#undef BOOST_OPTIONAL_STD_SWAP_INTRODUCED_AT_NS_SCOPE
+
 } // namespace optional_detail
 
 template<class T> inline void swap ( optional<T>& x, optional<T>& y )