libsigcplusplus · kjellahl · Jun 2, 2021 · May 26, 2021
diff --git a/sigc++/functors/slot.h b/sigc++/functors/slot.h
@@ -151,7 +151,8 @@ struct slot_call
   static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg>... a_)
   {
     auto typed_rep = static_cast<typed_slot_rep<T_functor>*>(rep);
-    return (*typed_rep->functor_).template operator()<type_trait_take_t<T_arg>...>(a_...);
+    return (*typed_rep->functor_).template operator()<type_trait_take_t<T_arg>...>(
+      std::forward<type_trait_take_t<T_arg>>(a_)...);
   }
 
   /** Forms a function pointer from call_it().
@@ -220,7 +221,7 @@ class slot<T_return(T_arg...)> : public slot_base
     {
       return std::invoke(sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_),
         slot_base::rep_,
-        a...);
+        std::forward<type_trait_take_t<T_arg>>(a)...);
     }
 
     return T_return();

diff --git a/sigc++/signal.h b/sigc++/signal.h
@@ -363,7 +363,9 @@ struct signal_emit<void, void, T_arg...>
       if (slot.empty() || slot.blocked())
         continue;
 
-      (sigc::internal::function_pointer_cast<call_type>(slot.rep_->call_))(slot.rep_, a...);
+      (sigc::internal::function_pointer_cast<call_type>(slot.rep_->call_))(
+        slot.rep_,
+        std::forward<type_trait_take_t<T_arg>>(a)...);
     }
   }
 };
@@ -450,11 +452,13 @@ class signal_with_accumulator : public signal_base
   decltype(auto) emit(type_trait_take_t<T_arg>... a) const
   {
     using emitter_type = internal::signal_emit<T_return, T_accumulator, T_arg...>;
-    return emitter_type::emit(impl_, a...);
+    return emitter_type::emit(impl_, std::forward<type_trait_take_t<T_arg>>(a)...);
   }
 
   /** Triggers the emission of the signal (see emit()). */
-  decltype(auto) operator()(type_trait_take_t<T_arg>... a) const { return emit(a...); }
+  decltype(auto) operator()(type_trait_take_t<T_arg>... a) const {
+    return emit(std::forward<type_trait_take_t<T_arg>>(a)...);
+  }
 
   /** Creates a functor that calls emit() on this signal.
    * @code

diff --git a/sigc++/type_traits.h b/sigc++/type_traits.h
@@ -52,6 +52,13 @@ struct type_trait<const T_type&>
   using take = const T_type&;
 };
 
+template<typename T_type>
+struct type_trait<T_type&&>
+{
+  using pass = T_type&&;
+  using take = T_type&&;
+};
+
 template<>
 struct type_trait<void>
 {

diff --git a/tests/memleakcheck.sh b/tests/memleakcheck.sh
@@ -9,8 +9,8 @@ for testprog in  test_accum_iter test_accumulated test_bind test_bind_as_slot \
   test_copy_invalid_slot test_cpp11_lambda test_custom test_disconnect \
   test_disconnect_during_emit test_exception_catch test_hide \
   test_limit_reference test_member_method_trait test_mem_fun test_ptr_fun \
-  test_retype test_retype_return test_signal test_signal_move test_size \
-  test_slot test_slot_disconnect test_slot_move test_trackable \
+  test_retype test_retype_return test_rvalue_ref test_signal test_signal_move \
+  test_size test_slot test_slot_disconnect test_slot_move test_trackable \
   test_trackable_move test_track_obj test_tuple_cdr test_tuple_end \
   test_tuple_for_each test_tuple_start test_tuple_transform_each \
   test_visit_each test_visit_each_trackable test_weak_raw_ptr

diff --git a/tests/meson.build b/tests/meson.build
@@ -28,6 +28,7 @@ test_programs = [
   [[], 'test_ptr_fun', ['test_ptr_fun.cc', 'testutilities.cc']],
   [[], 'test_retype', ['test_retype.cc', 'testutilities.cc']],
   [[], 'test_retype_return', ['test_retype_return.cc', 'testutilities.cc']],
+  [[], 'test_rvalue_ref', ['test_rvalue_ref.cc', 'testutilities.cc']],
   [[], 'test_signal', ['test_signal.cc', 'testutilities.cc']],
   [[], 'test_signal_move', ['test_signal_move.cc', 'testutilities.cc']],
   [[], 'test_size', ['test_size.cc', 'testutilities.cc']],

diff --git a/tests/test_rvalue_ref.cc b/tests/test_rvalue_ref.cc
@@ -0,0 +1,55 @@
+#include "testutilities.h"
+#include <iostream>
+#include <sigc++/signal.h>
+
+struct MoveableStruct {};
+
+namespace
+{
+TestUtilities* util = nullptr;
+std::ostringstream result_stream;
+
+struct foo
+{
+  void operator()(MoveableStruct &&x)
+  {
+    result_stream << "foo(MoveableStruct&&)";
+  }
+};
+
+} // end anonymous namespace
+
+void
+test_signal()
+{
+  sigc::signal<void (MoveableStruct &&)> signal;
+  foo f;
+  signal.connect(f);
+  MoveableStruct x;
+  signal(std::move(x));
+  util->check_result(result_stream, "foo(MoveableStruct&&)");
+}
+
+void
+test_slot()
+{
+  sigc::slot<void (MoveableStruct &&)> slot;
+  foo f;
+  slot = f;
+  MoveableStruct x;
+  slot(std::move(x));
+  util->check_result(result_stream, "foo(MoveableStruct&&)");
+}
+
+int
+main(int argc, char* argv[])
+{
+  util = TestUtilities::get_instance();
+  if (!util->check_command_args(argc, argv))
+    return util->get_result_and_delete_instance() ? EXIT_SUCCESS : EXIT_FAILURE;
+
+  test_signal();
+  test_slot();
+
+  return util->get_result_and_delete_instance() ? EXIT_SUCCESS : EXIT_FAILURE;
+} // end main()