Add boost::ignore_unused()

test/Jamfile.v2

@@ -36,4 +36,8 @@ test-suite "core"
         [ compile-fail explicit_operator_bool_compile_fail_conv_pvoid.cpp ]
         [ compile-fail explicit_operator_bool_compile_fail_delete.cpp ]
         [ compile-fail explicit_operator_bool_compile_fail_shift.cpp ]
+
+	[ compile ignore_unused_test.cpp : <toolset>gcc:<cxxflags>"-Wunused-variable -Wunused-local-typedefs -Werror"
+                                           <toolset>clang:<cxxflags>"-Wunused-variable -Werror"
+                                           <toolset>msvc:<cxxflags>"/we4100 /we4101" ]
     ;

test/ignore_unused_test.cpp

@@ -0,0 +1,65 @@
+// Copyright (c) 2014 Adam Wulkiewicz, Lodz, Poland.
+//
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+//#include <boost/utility/ignore_unused.hpp>
+#include <boost/utility.hpp>
+
+int main()
+{
+    {
+        int a;
+        boost::ignore_unused(a);
+    }
+    {
+        int a, b;
+        boost::ignore_unused(a, b);
+    }
+    {
+        int a, b, c;
+        boost::ignore_unused(a, b, c);
+    }
+    {
+        int a, b, c, d;
+        boost::ignore_unused(a, b, c, d);
+    }
+    {
+        int a, b, c, d, e;
+        boost::ignore_unused(a, b, c, d, e);
+    }
+
+    {
+        typedef int a;
+        boost::ignore_unused<a>();
+    }
+    {
+        typedef int a;
+        typedef int b;
+        boost::ignore_unused<a, b>();
+    }
+    {
+        typedef int a;
+        typedef int b;
+        typedef int c;
+        boost::ignore_unused<a, b, c>();
+    }
+    {
+        typedef int a;
+        typedef int b;
+        typedef int c;
+        typedef int d;
+        boost::ignore_unused<a, b, c, d>();
+    }
+    {
+        typedef int a;
+        typedef int b;
+        typedef int c;
+        typedef int d;
+        typedef int e;
+        boost::ignore_unused<a, b, c, d, e>();
+    }
+
+    return 0;
+}