diff --git a/include/boost/python/errors.hpp b/include/boost/python/errors.hpp
index 390f3b61..4c47aca8 100644
--- a/include/boost/python/errors.hpp
+++ b/include/boost/python/errors.hpp
@@ -20,7 +20,7 @@ struct BOOST_PYTHON_DECL argument_error : error_already_set {};
 
 // Handles exceptions caught just before returning to Python code.
 // Returns true iff an exception was caught.
-BOOST_PYTHON_DECL bool handle_exception_impl(function0<void> const&);
+BOOST_PYTHON_DECL bool handle_exception_impl(function0<void>);
 
 template <class T>
 bool handle_exception(T f)
diff --git a/src/errors.cpp b/src/errors.cpp
index 882d2917..05e40658 100644
--- a/src/errors.cpp
+++ b/src/errors.cpp
@@ -17,7 +17,7 @@
 namespace boost { namespace python {
 
 // IMPORTANT: this function may only be called from within a catch block!
-BOOST_PYTHON_DECL bool handle_exception_impl(function0<void> const& f)
+BOOST_PYTHON_DECL bool handle_exception_impl(function0<void> f)
 {
     try
     {