Use an array for sort function storage, since it's always fixed-size

src/gui/dialogs/game_load.cpp

@@ -186,7 +186,7 @@ void tgame_load::fill_game_list(twindow& window,
 
 		list.add_row(data);
 	}
-	std::vector<tgenerator_::torder_func> order_funcs(2);
+	generator_sort_array order_funcs;
 	order_funcs[0] = std::bind(&tgame_load::compare_name, this, _1, _2);
 	order_funcs[1] = std::bind(&tgame_load::compare_name_rev, this, _1, _2);
 	list.set_column_order(0, order_funcs);

src/gui/dialogs/preferences_dialog.cpp

@@ -878,7 +878,7 @@ void tpreferences::initialize_members(twindow& window)
 
 	tlistbox& hotkey_list = find_widget<tlistbox>(&window, "list_hotkeys", false);
 
-	std::vector<tgenerator_::torder_func> order_funcs(2);
+	generator_sort_array order_funcs;
 
 	order_funcs[0] = hotkey_sort_by_desc<false>(visible_hotkeys_);
 	order_funcs[1] = hotkey_sort_by_desc<true>(visible_hotkeys_);

src/gui/dialogs/unit_create.cpp

@@ -158,7 +158,7 @@ void tunit_create::pre_show(twindow& window)
 				  << std::endl;
 	}
 
-	std::vector<tgenerator_::torder_func> order_funcs(2);
+	generator_sort_array order_funcs;
 	order_funcs[0] = std::bind(&tunit_create::compare_race, this, _1, _2);
 	order_funcs[1] = std::bind(&tunit_create::compare_race_rev, this, _1, _2);
 	list.set_column_order(0, order_funcs);

src/gui/dialogs/unit_recall.cpp

@@ -122,7 +122,7 @@ static std::string trait_key(unit_const_ptr u)
 }
 
 template<typename Fnc>
-void tunit_recall::init_sorting_option(std::vector<tgenerator_::torder_func>& order_funcs, Fnc filter_on)
+void tunit_recall::init_sorting_option(generator_sort_array& order_funcs, Fnc filter_on)
 {
 	order_funcs[0] = [this, filter_on](unsigned i1, unsigned i2) {
 		return filter_on((*recall_list_)[i1]) < filter_on((*recall_list_)[i2]);
@@ -249,7 +249,7 @@ void tunit_recall::pre_show(twindow& window)
 		filter_options_.push_back(filter_text);
 	}
 
-	std::vector<tgenerator_::torder_func> order_funcs(2);
+	generator_sort_array order_funcs;
 
 	init_sorting_option(order_funcs, std::bind(&tstr_key, _1, &unit::type_name));
 	list.set_column_order(0, order_funcs);

src/gui/dialogs/unit_recall.hpp

@@ -55,7 +55,7 @@ private:
 	std::vector<std::string> last_words_;
 
 	template<typename T>
-	void init_sorting_option(std::vector<tgenerator_::torder_func>& order_funcs, T filter_on);
+	void init_sorting_option(generator_sort_array& order_funcs, T filter_on);
 
 	/** Callbacks */
 	void list_item_clicked(twindow& window);

src/gui/widgets/generator.hpp

@@ -364,6 +364,8 @@ protected:
 	virtual unsigned get_item_at_ordered(unsigned index_ordered) const = 0;
 };
 
+using generator_sort_array = std::array<tgenerator_::torder_func, 2>;
+
 } // namespace gui2
 
 #endif

src/gui/widgets/listbox.cpp

@@ -593,7 +593,7 @@ void tlistbox::order_by(const tgenerator_::torder_func& func)
 	need_layout_ = true;
 }
 
-void tlistbox::set_column_order(unsigned col, const std::vector<tgenerator_::torder_func>& func)
+void tlistbox::set_column_order(unsigned col, const generator_sort_array& func)
 {
 	if(col >= orders_.size()) {
 		orders_.resize(col + 1);

src/gui/widgets/listbox.hpp

@@ -234,7 +234,7 @@ public:
 
 	void order_by(const tgenerator_::torder_func& func);
 
-	void set_column_order(unsigned col, const std::vector<tgenerator_::torder_func>& func);
+	void set_column_order(unsigned col, const generator_sort_array& func);
 protected:
 	/***** ***** ***** ***** keyboard functions ***** ***** ***** *****/
 
@@ -308,7 +308,7 @@ private:
 
 	bool need_layout_;
 
-	typedef std::vector<std::pair<tselectable_*, std::vector<tgenerator_::torder_func> > > torder_list;
+	typedef std::vector<std::pair<tselectable_*, generator_sort_array > > torder_list;
 	torder_list orders_;
 	/**
 	 * Resizes the content.