From 83dcd9122304377f9c41765cbf2ef643ff17fa39 Mon Sep 17 00:00:00 2001
From: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
Date: Fri, 25 May 2007 14:13:23 +0200
Subject: [PATCH] make Callback use a separate empty type

---
 SConstruct          | 1 +
 src/core/callback.h | 3 +--
 src/core/empty.h    | 8 ++++++++
 3 files changed, 10 insertions(+), 2 deletions(-)
 create mode 100644 src/core/empty.h

diff --git a/SConstruct b/SConstruct
index f759a3960..ca6222c26 100644
--- a/SConstruct
+++ b/SConstruct
@@ -61,6 +61,7 @@ core.add_headers ([
 ])
 core.add_inst_headers([
     'system-wall-clock-ms.h',
+    'empty.h',
     'callback.h',
     'ptr.h',
     'object.h',
diff --git a/src/core/callback.h b/src/core/callback.h
index efeb44be2..000346985 100644
--- a/src/core/callback.h
+++ b/src/core/callback.h
@@ -24,6 +24,7 @@
 
 #include "ptr.h"
 #include "fatal-error.h"
+#include "empty.h"
 
 namespace ns3 {
 
@@ -56,8 +57,6 @@ namespace ns3 {
  * and relies on a reference list rather than autoPtr to hold
  * the pointer.
  */
-class empty {};
-
 template <typename T>
 struct CallbackTraits;
 
diff --git a/src/core/empty.h b/src/core/empty.h
new file mode 100644
index 000000000..6b89b9cdb
--- /dev/null
+++ b/src/core/empty.h
@@ -0,0 +1,8 @@
+#ifndef EMPTY_H
+#define EMPTY_H
+
+namespace ns3 {
+class empty {};
+}
+
+#endif /* EMPTY_H */