diff --git boost/spirit/home/classic/core/composite/no_actions.hpp boost/spirit/home/classic/core/composite/no_actions.hpp
index 638a297..aa42f96 100644
--- boost/spirit/home/classic/core/composite/no_actions.hpp
+++ boost/spirit/home/classic/core/composite/no_actions.hpp
@@ -42,7 +42,12 @@ struct no_actions_action_policy:
         AttrT&              val,
         IteratorT const&    first,
         IteratorT const&    last) const
-    {}
+    {
+        (void) actor;
+        (void) val;
+        (void) first;
+        (void) last;
+    }
 };
 
 //-----------------------------------------------------------------------------
diff --git boost/spirit/home/classic/core/non_terminal/impl/grammar.ipp boost/spirit/home/classic/core/non_terminal/impl/grammar.ipp
index 3b25b3d..29951a6 100644
--- boost/spirit/home/classic/core/non_terminal/impl/grammar.ipp
+++ boost/spirit/home/classic/core/non_terminal/impl/grammar.ipp
@@ -85,6 +85,7 @@ struct grammar_definition
 
         grammar_helper_list& operator=(grammar_helper_list const& x)
         {   // Does _not_ copy the helpers member !
+            (void) x;
             return *this;
         }
 
diff --git boost/spirit/home/classic/meta/impl/refactoring.ipp boost/spirit/home/classic/meta/impl/refactoring.ipp
index 61cc6b5..f5a3039 100644
--- boost/spirit/home/classic/meta/impl/refactoring.ipp
+++ boost/spirit/home/classic/meta/impl/refactoring.ipp
@@ -326,6 +326,7 @@ namespace impl {
         parse(ParserT const &, ScannerT const& scan, ActionT const &action,
             NestedT const& nested_d)
         {
+            (void) nested_d;
             return action.parse(scan);
         }
     };
diff --git boost/spirit/home/classic/phoenix/tuples.hpp boost/spirit/home/classic/phoenix/tuples.hpp
index 50cec6b..78ffc75 100644
--- boost/spirit/home/classic/phoenix/tuples.hpp
+++ boost/spirit/home/classic/phoenix/tuples.hpp
@@ -211,7 +211,7 @@ struct tuple_element
     typedef nil_t& rtype;
     typedef nil_t const& crtype;
 
-    static nil_t    get(TupleT const& t)    { return nil_t(); }
+    static nil_t    get(TupleT const& t)    { (void) t; return nil_t(); }
 };
 
 //////////////////////////////////
diff --git boost/spirit/home/classic/utility/impl/chset.ipp boost/spirit/home/classic/utility/impl/chset.ipp
index 3017035..cc85064 100644
--- boost/spirit/home/classic/utility/impl/chset.ipp
+++ boost/spirit/home/classic/utility/impl/chset.ipp
@@ -130,7 +130,7 @@ inline chset<CharT>::chset(anychar_parser /*arg*/)
 
 template <typename CharT>
 inline chset<CharT>::chset(nothing_parser arg_)
-: ptr(new basic_chset<CharT>()) {}
+: ptr(new basic_chset<CharT>()) { (void) arg_; }
 
 template <typename CharT>
 inline chset<CharT>::chset(chlit<CharT> const& arg_)
@@ -184,6 +184,7 @@ template <typename CharT>
 inline chset<CharT>&
 chset<CharT>::operator=(anychar_parser rhs)
 {
+    (void) rhs;
     utility::impl::detach_clear(ptr);
     ptr->set(
         (std::numeric_limits<CharT>::min)(),
@@ -196,6 +197,7 @@ template <typename CharT>
 inline chset<CharT>&
 chset<CharT>::operator=(nothing_parser rhs)
 {
+    (void) rhs;
     utility::impl::detach_clear(ptr);
     return *this;
 }
diff --git boost/token_functions.hpp boost/token_functions.hpp
index 4d1a1df..203f6b3 100644
--- boost/token_functions.hpp
+++ boost/token_functions.hpp
@@ -309,7 +309,11 @@ namespace boost{
   template <>
   struct assign_or_plus_equal<std::input_iterator_tag> {
     template<class Iterator, class Token>
-    static void assign(Iterator b, Iterator e, Token &t) { }
+    static void assign(Iterator b, Iterator e, Token &t) {
+      (void) b;
+      (void) e;
+      (void) t;
+    }
     template<class Token, class Value> 
     static void plus_equal(Token &t, const Value &v) {
       t += v;