Merge branch 'noexcept-event-tables'

Allow using noexcept handlers in event tables.

See https://github.com/wxWidgets/wxWidgets/pull/1788

docs/doxygen/mainpages/const_cpp.h

@@ -191,6 +191,7 @@ Currently the following symbols exist:
 @itemdef{wxHAS_NATIVE_ANIMATIONCTRL, Defined if native wxAnimationCtrl class is being used (this symbol only exists in wxWidgets 3.1.4 and later).}
 @itemdef{wxHAS_NATIVE_DATAVIEWCTRL, Defined if native wxDataViewCtrl class is being used (this symbol only exists in wxWidgets 3.1.4 and later).}
 @itemdef{wxHAS_NATIVE_WINDOW, Defined if wxNativeWindow class is available.}
+@itemdef{wxHAS_NOEXCEPT, Defined if the currently used compiler supports C++11 @c noexcept. @c wxNOEXCEPT is defined as this keyword in this case, and as nothing otherwise.}
 @itemdef{wxHAS_NULLPTR_T, Defined if the currently used compiler supports C++11 @c nullptr.}
 @itemdef{wxHAS_IMAGES_IN_RESOURCES, Defined if <a href="http://en.wikipedia.org/wiki/Resource_(Windows)">
     Windows resource files</a> or OS/2 resource files are available on the current platform.}

include/wx/defs.h

@@ -285,12 +285,19 @@ typedef short int WXTYPE;
     #define wxOVERRIDE
 #endif /*  HAVE_OVERRIDE */
 
-/* same for defaulted member function keyword */
+/* same for more C++11 keywords which don't have such historic baggage as
+   override and so can be detected by just testing for C++11 support (which
+   still requires handling MSVS specially, unfortunately) */
 #if __cplusplus >= 201103L || wxCHECK_VISUALC_VERSION(14)
     #define wxHAS_MEMBER_DEFAULT
     #define wxMEMBER_DEFAULT = default
+
+    #define wxHAS_NOEXCEPT
+    #define wxNOEXCEPT noexcept
 #else
     #define wxMEMBER_DEFAULT
+
+    #define wxNOEXCEPT
 #endif
 
 /*

include/wx/event.h

@@ -144,9 +144,43 @@ inline wxEventFunction wxEventFunctionCast(void (wxEvtHandler::*func)(T&))
     wxGCC_WARNING_RESTORE_CAST_FUNCTION_TYPE()
 }
 
+// Special hack to remove "noexcept" from the function type when using C++17 or
+// later: static_cast<> below would fail to cast a member function pointer to a
+// member of a derived class to the base class if noexcept is specified for the
+// former, so remove it first if necessary.
+#if __cplusplus >= 201703L
+
+namespace wxPrivate
+{
+
+// Generic template version, doing nothing.
+template <typename T>
+struct RemoveNoexceptEventHandler
+{
+    using type = T;
+};
+
+// Specialization removing noexcept when it's specified.
+//
+// Note that this doesn't pretend to be generally suitable, this is just enough
+// to work in our particular case.
+template <typename R, typename C, typename E>
+struct RemoveNoexceptEventHandler<R (C::*)(E&) noexcept>
+{
+    using type = R (C::*)(E&);
+};
+
+} // namespace wxPrivate
+
+#define wxREMOVE_NOEXCEPT_EVENT_HANDLER(pmf) \
+    static_cast<wxPrivate::RemoveNoexceptEventHandler<decltype(pmf)>::type>(pmf)
+#else
+#define wxREMOVE_NOEXCEPT_EVENT_HANDLER(pmf) pmf
+#endif
+
 // Try to cast the given event handler to the correct handler type:
 #define wxEVENT_HANDLER_CAST( functype, func ) \
-    wxEventFunctionCast(static_cast<functype>(&func))
+    wxEventFunctionCast(static_cast<functype>(wxREMOVE_NOEXCEPT_EVENT_HANDLER(&func)))
 
 
 // The tag is a type associated to the event type (which is an integer itself,

tests/events/evthandler.cpp

@@ -122,6 +122,9 @@ public:
     void OnEvent(wxEvent&) { g_called.method = true; }
     void OnAnotherEvent(AnotherEvent&);
     void OnIdle(wxIdleEvent&) { g_called.method = true; }
+#ifdef wxHAS_NOEXCEPT
+    void OnIdleNoExcept(wxIdleEvent&) noexcept { }
+#endif
 
 private:
     wxDECLARE_EVENT_TABLE();
@@ -138,6 +141,10 @@ wxBEGIN_EVENT_TABLE(MyClassWithEventTable, wxEvtHandler)
     EVT_MYEVENT(MyClassWithEventTable::OnMyEvent)
     EVT_MYEVENT(MyClassWithEventTable::OnEvent)
 
+#ifdef wxHAS_NOEXCEPT
+    EVT_IDLE(MyClassWithEventTable::OnIdleNoExcept)
+#endif
+
     // this shouldn't compile:
     //EVT_MYEVENT(MyClassWithEventTable::OnIdle)
     //EVT_IDLE(MyClassWithEventTable::OnAnotherEvent)