From 333ed0a327d4c8acc807a3d3a0bc333383b35119 Mon Sep 17 00:00:00 2001
From: Eric Friedman <ebf@users.sourceforge.net>
Date: Thu, 17 Jul 2003 08:45:31 +0000
Subject: [PATCH] NO_VOID_RETURNS workaround.

[SVN r19167]
---
 include/boost/variant/visitor_ptr.hpp | 48 +++++++++++++++++++++++----
 1 file changed, 41 insertions(+), 7 deletions(-)

diff --git a/include/boost/variant/visitor_ptr.hpp b/include/boost/variant/visitor_ptr.hpp
index 4eacb6f..e5fbb22 100644
--- a/include/boost/variant/visitor_ptr.hpp
+++ b/include/boost/variant/visitor_ptr.hpp
@@ -21,8 +21,9 @@
 
 #include "boost/mpl/apply_if.hpp"
 #include "boost/mpl/identity.hpp"
-#include "boost/type_traits/is_reference.hpp"
 #include "boost/type_traits/add_reference.hpp"
+#include "boost/type_traits/is_reference.hpp"
+#include "boost/type_traits/is_void.hpp"
 
 namespace boost {
 
@@ -35,12 +36,14 @@ namespace boost {
 struct bad_visit
     : std::exception
 {
-public:
+public: // std::exception interface
+
     virtual const char * what() const throw()
     {
         return "boost::bad_visit: "
                "failed visitation using boost::apply_visitor";
     }
+
 };
 
 
@@ -81,17 +84,48 @@ public: // structors
 
 public: // static visitor interfaces
 
-    result_type operator()(argument_fwd_type operand) const
-    {
-        return visitor_(operand);
-    }
-
     template <typename U>
     result_type operator()(const U&) const
     {
         throw bad_visit();
     }
 
+#if !defined(BOOST_NO_VOID_RETURNS)
+
+public: // static visitor interfaces, cont.
+
+    result_type operator()(argument_fwd_type operand) const
+    {
+        return visitor_(operand);
+    }
+
+#else // defined(BOOST_NO_VOID_RETURNS)
+
+private: // helpers, for static visitor interfaces (below)
+
+    result_type execute_impl(argument_fwd_type operand, mpl::false_) const
+    {
+        return visitor_(operand);
+    }
+
+        BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(void)
+    execute_impl(argument_fwd_type operand, mpl::true_) const
+    {
+        visitor_(operand);
+        BOOST_VARIANT_AUX_RETURN_VOID;
+    }
+
+public: // static visitor interfaces, cont.
+
+        BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
+    operator()(argument_fwd_type operand) const
+    {
+        typedef typename is_void<result_type>::type has_void_result;
+        return execute_impl(operand, has_void_result());
+    }
+
+#endif // BOOST_NO_VOID_RETURNS workaround
+
 };
 
 template <typename R, typename T>