diff --git a/asio/include/asio/detail/impl/kqueue_reactor.ipp b/asio/include/asio/detail/impl/kqueue_reactor.ipp
index feff3f9a..e57f6caf 100644
--- a/asio/include/asio/detail/impl/kqueue_reactor.ipp
+++ b/asio/include/asio/detail/impl/kqueue_reactor.ipp
@@ -164,6 +164,14 @@ int kqueue_reactor::register_internal_descriptor(
   return 0;
 }
 
+void kqueue_reactor::move_descriptor(socket_type,
+    kqueue_reactor::per_descriptor_data& target_descriptor_data,
+    kqueue_reactor::per_descriptor_data& source_descriptor_data)
+{
+  target_descriptor_data = source_descriptor_data;
+  source_descriptor_data = 0;
+}
+
 void kqueue_reactor::start_op(int op_type, socket_type descriptor,
     kqueue_reactor::per_descriptor_data& descriptor_data,
     reactor_op* op, bool allow_speculative)
diff --git a/asio/include/asio/detail/kqueue_reactor.hpp b/asio/include/asio/detail/kqueue_reactor.hpp
index 2b34220c..16b9b2ee 100644
--- a/asio/include/asio/detail/kqueue_reactor.hpp
+++ b/asio/include/asio/detail/kqueue_reactor.hpp
@@ -99,6 +99,11 @@ public:
       int op_type, socket_type descriptor,
       per_descriptor_data& descriptor_data, reactor_op* op);
 
+  // Move descriptor registration from one descriptor_data object to another.
+  ASIO_DECL void move_descriptor(socket_type descriptor,
+      per_descriptor_data& target_descriptor_data,
+      per_descriptor_data& source_descriptor_data);
+
   // Post a reactor operation for immediate completion.
   void post_immediate_completion(reactor_op* op)
   {