diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
index 4eaa14b3b0..182bcbc747 100644
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -724,7 +724,7 @@ const StringID _engine_sort_listing[][14] = {{
 }};
 
 /** Filters vehicles by cargo and engine (in case of rail vehicle). */
-static bool CDECL CargoAndEngineFilter(const EngineID *eid, const CargoID cid)
+static bool CargoAndEngineFilter(const EngineID *eid, const CargoID cid)
 {
 	if (cid == CF_ANY) {
 		return true;
diff --git a/src/industry_gui.cpp b/src/industry_gui.cpp
index da784465c7..60b6bbbf89 100644
--- a/src/industry_gui.cpp
+++ b/src/industry_gui.cpp
@@ -1281,7 +1281,7 @@ enum CargoFilterSpecialType {
  * @param cargoes The accepted and produced cargo pair to look for.
  * @return bool Whether the given cargoes accepted and produced by the industry.
  */
-static bool CDECL CargoFilter(const Industry * const *industry, const std::pair<CargoID, CargoID> &cargoes)
+static bool CargoFilter(const Industry * const *industry, const std::pair<CargoID, CargoID> &cargoes)
 {
 	auto accepted_cargo = cargoes.first;
 	auto produced_cargo = cargoes.second;
diff --git a/src/network/network_content_gui.cpp b/src/network/network_content_gui.cpp
index 0130bc9800..84e4c92e78 100644
--- a/src/network/network_content_gui.cpp
+++ b/src/network/network_content_gui.cpp
@@ -438,7 +438,7 @@ class NetworkContentListWindow : public Window, ContentCallback {
 	}
 
 	/** Filter content by tags/name */
-	static bool CDECL TagNameFilter(const ContentInfo * const *a, ContentListFilterData &filter)
+	static bool TagNameFilter(const ContentInfo * const *a, ContentListFilterData &filter)
 	{
 		filter.string_filter.ResetState();
 		for (auto &tag : (*a)->tags) filter.string_filter.AddLine(tag.c_str());
@@ -448,7 +448,7 @@ class NetworkContentListWindow : public Window, ContentCallback {
 	}
 
 	/** Filter content by type, but still show content selected for download. */
-	static bool CDECL TypeOrSelectedFilter(const ContentInfo * const *a, ContentListFilterData &filter)
+	static bool TypeOrSelectedFilter(const ContentInfo * const *a, ContentListFilterData &filter)
 	{
 		if (filter.types.none()) return true;
 		if (filter.types[(*a)->type]) return true;
diff --git a/src/network/network_gui.cpp b/src/network/network_gui.cpp
index 21d86ad140..d34c5e3455 100644
--- a/src/network/network_gui.cpp
+++ b/src/network/network_gui.cpp
@@ -389,7 +389,7 @@ protected:
 		}
 	}
 
-	static bool CDECL NGameSearchFilter(NetworkGameList * const *item, StringFilter &sf)
+	static bool NGameSearchFilter(NetworkGameList * const *item, StringFilter &sf)
 	{
 		assert(item != nullptr);
 		assert((*item) != nullptr);
diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
index 868f956f3c..450e70433b 100644
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -1440,7 +1440,7 @@ private:
 	}
 
 	/** Filter grfs by tags/name */
-	static bool CDECL TagNameFilter(const GRFConfig * const *a, StringFilter &filter)
+	static bool TagNameFilter(const GRFConfig * const *a, StringFilter &filter)
 	{
 		filter.ResetState();
 		filter.AddLine((*a)->GetName());
diff --git a/src/object_gui.cpp b/src/object_gui.cpp
index 8fcf034a48..365bec6d93 100644
--- a/src/object_gui.cpp
+++ b/src/object_gui.cpp
@@ -135,7 +135,7 @@ public:
 	}
 
 	/** Filter object classes by class name. */
-	static bool CDECL TagNameFilter(ObjectClassID const *oc, StringFilter &filter)
+	static bool TagNameFilter(ObjectClassID const *oc, StringFilter &filter)
 	{
 		ObjectClass *objclass = ObjectClass::Get(*oc);
 		char buffer[DRAW_STRING_BUFFER];
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 8f9bd8f27b..1fa620ea59 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -1185,7 +1185,7 @@ public:
 	}
 
 	/** Filter station classes by class name. */
-	static bool CDECL TagNameFilter(StationClassID const * sc, StringFilter &filter)
+	static bool TagNameFilter(StationClassID const * sc, StringFilter &filter)
 	{
 		char buffer[DRAW_STRING_BUFFER];
 		GetString(buffer, StationClass::Get(*sc)->name, lastof(buffer));
diff --git a/src/road_gui.cpp b/src/road_gui.cpp
index 46b1af7262..654ce70f00 100644
--- a/src/road_gui.cpp
+++ b/src/road_gui.cpp
@@ -1341,7 +1341,7 @@ public:
 	}
 
 	/** Filter classes by class name. */
-	static bool CDECL TagNameFilter(RoadStopClassID const *sc, StringFilter &filter)
+	static bool TagNameFilter(RoadStopClassID const *sc, StringFilter &filter)
 	{
 		char buffer[DRAW_STRING_BUFFER];
 		GetString(buffer, RoadStopClass::Get(*sc)->name, lastof(buffer));
diff --git a/src/signs_gui.cpp b/src/signs_gui.cpp
index e4446fea47..f148b7c388 100644
--- a/src/signs_gui.cpp
+++ b/src/signs_gui.cpp
@@ -90,7 +90,7 @@ struct SignList {
 	}
 
 	/** Filter sign list by sign name */
-	static bool CDECL SignNameFilter(const Sign * const *a, StringFilter &filter)
+	static bool SignNameFilter(const Sign * const *a, StringFilter &filter)
 	{
 		/* Same performance benefit as above for sorting. */
 		const char *a_name = (*a)->name.empty() ? SignList::default_name : (*a)->name.c_str();
@@ -101,14 +101,14 @@ struct SignList {
 	}
 
 	/** Filter sign list excluding OWNER_DEITY */
-	static bool CDECL OwnerDeityFilter(const Sign * const *a, StringFilter &filter)
+	static bool OwnerDeityFilter(const Sign * const *a, StringFilter &filter)
 	{
 		/* You should never be able to edit signs of owner DEITY */
 		return (*a)->owner != OWNER_DEITY;
 	}
 
 	/** Filter sign list by owner */
-	static bool CDECL OwnerVisibilityFilter(const Sign * const *a, StringFilter &filter)
+	static bool OwnerVisibilityFilter(const Sign * const *a, StringFilter &filter)
 	{
 		assert(!HasBit(_display_opt, DO_SHOW_COMPETITOR_SIGNS));
 		/* Hide sign if non-own signs are hidden in the viewport */
diff --git a/src/sortlist_type.h b/src/sortlist_type.h
index 837c33e089..28a9a70ef2 100644
--- a/src/sortlist_type.h
+++ b/src/sortlist_type.h
@@ -46,7 +46,7 @@ template <typename T, typename F = const char*>
 class GUIList : public std::vector<T> {
 public:
 	typedef bool SortFunction(const T&, const T&);  ///< Signature of sort function.
-	typedef bool CDECL FilterFunction(const T*, F); ///< Signature of filter function.
+	typedef bool FilterFunction(const T*, F); ///< Signature of filter function.
 
 protected:
 	SortFunction * const *sort_func_list;     ///< the sort criteria functions
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 86570b36b9..75c0abec90 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -275,7 +275,7 @@ void BaseVehicleListWindow::BuildVehicleList()
 }
 
 /** Cargo filter functions */
-static bool CDECL CargoFilter(const Vehicle * const *vid, const CargoID cid)
+static bool CargoFilter(const Vehicle * const *vid, const CargoID cid)
 {
 	if (cid == BaseVehicleListWindow::CF_ANY) {
 		return true;
@@ -308,7 +308,7 @@ static bool CDECL CargoFilter(const Vehicle * const *vid, const CargoID cid)
 	}
 }
 
-static bool CDECL GroupCargoFilter(const GUIVehicleGroup* group, const CargoID cid)
+static bool GroupCargoFilter(const GUIVehicleGroup* group, const CargoID cid)
 {
 	if (cid == BaseVehicleListWindow::CF_ANY) return true;
 	for (VehicleList::const_iterator v = group->vehicles_begin; v != group->vehicles_end; ++v) {