Here is a list of all documented functions, variables, defines, enums, and typedefs with links to the documentation:

### - d -

- DA_ALWAYS_GO : order_type.h
- DA_SERVICE : order_type.h
- DA_STOP : order_type.h
- DATA_DIR : fileio_type.h
- DAY_TICKS : date_type.h
- DAYS_IN_LEAP_YEAR : date_type.h
- DAYS_IN_YEAR : date_type.h
- DAYS_TILL_ORIGINAL_BASE_YEAR : date_type.h
- DC_ALL_TILES : command_type.h
- DC_AUTO : command_type.h
- DC_AUTOREPLACE : command_type.h
- DC_BANKRUPT : command_type.h
- DC_EXEC : command_type.h
- DC_NO_MODIFY_TOWN_RATING : command_type.h
- DC_NO_RAIL_OVERLAP : command_type.h
- DC_NO_TEST_TOWN_RATING : command_type.h
- DC_NO_WATER : command_type.h
- DC_NONE : command_type.h
- DC_QUERY_COST : command_type.h
- DeallocateSpecFromStation() : newgrf_station.cpp , newgrf_station.h
- DecHouseProcessingTime() : town_map.h
- DecIndustryTypeCount() : industry.h
- DECLARE_ENUM_AS_BIT_SET : enum_type.hpp , company_manager_face.h
- DECLARE_OLD_POOL() : company_base.h
- DECLARE_POSTFIX_INCREMENT() : rail_type.h , track_type.h , enum_type.hpp , direction_type.h , newgrf_station.h
- DecloneOrder() : order_cmd.cpp
- DecreaseBuildingCount() : newgrf_house.cpp , newgrf_house.h
- DedicatedFork() : dedicated.cpp
- DEF_COMMAND : command.cpp
- DEFAULT_GROUP : group_type.h
- delete_Hash() : queue.cpp , queue.h
- DeleteAllNonVitalWindows() : window.cpp , window_func.h
- DeleteAnimatedTile() : animated_tile.cpp , animated_tile_func.h
- DeleteCompanyWindows() : company_gui.h , window.cpp
- DeleteConstructionWindows() : window.cpp , window_func.h
- DeleteDepotHighlightOfVehicle() : depot_func.h , depot_gui.cpp
- DeleteDropDownList() : dropdown.cpp
- DeleteGroupHighlightOfVehicle() : group_gui.cpp , group_gui.h
- DeleteLastWagon() : train_cmd.cpp
- DeleteNewsItem() : news_gui.cpp
- DeleteNonVitalWindows() : window.cpp , window_func.h
- DeleteOrderWarnings() : order_cmd.cpp
- DeleteStationIfEmpty() : station_cmd.cpp
- DeleteStationNews() : news_func.h , news_gui.cpp
- DeleteTextBufferAll() : textbuf_gui.h , misc_gui.cpp
- DeleteTextBufferChar() : misc_gui.cpp , textbuf_gui.h
- DeleteVehicleNews() : news_func.h , news_gui.cpp
- DeleteVehicleOrders() : order_cmd.cpp , order_func.h
- DeleteWindowByClass() : window.cpp , window_func.h
- DeleteWindowById() : window.cpp , window_func.h
- DeliverGoods() : economy.cpp
- DeliverGoodsToIndustry() : economy.cpp
- Delta() : math_func.hpp
- DEPOT_DONT_CANCEL : vehicle_type.h
- DEPOT_LOCATE_HANGAR : vehicle_type.h
- DEPOT_MASS_SEND : vehicle_type.h
- DEPOT_SERVICE : vehicle_type.h
- DEPOT_WIDGET_H_SCROLL : depot_gui.cpp
- DEPOT_WIDGET_V_SCROLL : depot_gui.cpp
- DepotCommand : vehicle_type.h
- DepotWindowWidgets : depot_gui.cpp
- DestroyCompanyHQ() : unmovable_cmd.cpp
- DetermineBasePaths() : fileio.cpp
- DetermineGraphicsPack() : gfxinit.cpp
- DeterminePalette() : gfxinit.cpp
- DeterminePaths() : fileio.cpp , fileio_func.h
- DeterministicSpriteGroupAdjustOperation : newgrf_spritegroup.h
- DIAGDIR_BEGIN : direction_type.h
- DIAGDIR_END : direction_type.h
- diagdir_names : dbg_helpers.cpp
- DIAGDIR_NE : direction_type.h
- DIAGDIR_NW : direction_type.h
- DIAGDIR_SE : direction_type.h
- DIAGDIR_SW : direction_type.h
- DiagDirDiff : direction_type.h
- DIAGDIRDIFF_90LEFT : direction_type.h
- DIAGDIRDIFF_90RIGHT : direction_type.h
- DIAGDIRDIFF_REVERSE : direction_type.h
- DIAGDIRDIFF_SAME : direction_type.h
- DiagDirection : direction_type.h
- DiagdirReachesTrackdirs() : track_func.h
- DiagdirReachesTracks() : track_func.h
- DiagDirToAxis() : direction_func.h
- DiagDirToDiagTrack() : track_func.h
- DiagDirToDiagTrackBits() : track_func.h
- DiagDirToDiagTrackdir() : track_func.h
- DiagDirToDir() : direction_func.h
- DiagDirToRoadBits() : road_func.h
- DIR_BEGIN : direction_type.h
- DIR_E : direction_type.h
- DIR_END : direction_type.h
- DIR_N : direction_type.h
- DIR_NE : direction_type.h
- DIR_NW : direction_type.h
- DIR_S : direction_type.h
- DIR_SE : direction_type.h
- DIR_SW : direction_type.h
- DIR_W : direction_type.h
- DirDiff : direction_type.h
- DIRDIFF_45LEFT : direction_type.h
- DIRDIFF_45RIGHT : direction_type.h
- DIRDIFF_90LEFT : direction_type.h
- DIRDIFF_90RIGHT : direction_type.h
- DIRDIFF_REVERSE : direction_type.h
- DIRDIFF_SAME : direction_type.h
- DirDifference() : direction_func.h
- Direction : direction_type.h
- DirToDiagDir() : direction_func.h
- DisableStaticNewGRFInfluencingNonStaticNewGRFs() : newgrf.cpp
- DisallowedPPPofTrackAtPCP : elrail_data.h
- DisallowedRoadDirections : road_map.h
- Disaster_CoalMine_Init() : disaster_cmd.cpp
- Disaster_Helicopter_Init() : disaster_cmd.cpp
- Disaster_Small_Ufo_Init() : disaster_cmd.cpp
- Disaster_Zeppeliner_Init() : disaster_cmd.cpp
- DisasterTick_Airplane() : disaster_cmd.cpp
- DisasterTick_Big_Ufo() : disaster_cmd.cpp
- DisasterTick_Big_Ufo_Destroyer() : disaster_cmd.cpp
- DisasterTick_Helicopter() : disaster_cmd.cpp
- DisasterTick_Helicopter_Rotors() : disaster_cmd.cpp
- DisasterTick_Submarine() : disaster_cmd.cpp
- DisasterTick_Ufo() : disaster_cmd.cpp
- DisasterTick_Zeppeliner() : disaster_cmd.cpp
- DispatchLeftClickEvent() : window.cpp
- DispatchMouseWheelEvent() : window.cpp
- DispatchRightClickEvent() : window.cpp
- DisplayFlags : widget_type.h
- DistanceFromEdge() : map.cpp , map_func.h
- DistanceManhattan() : map.cpp , map_func.h
- DistanceMax() : map.cpp , map_func.h
- DistanceMaxPlusManhattan() : map.cpp , map_func.h
- DistanceSquare() : map.cpp , map_func.h
- DoAutosave() : openttd.cpp
- DoBuildShiplift() : water_cmd.cpp
- DockToolbarWidgets : dock_gui.cpp
- DoClearTownHouseHelper() : town_cmd.cpp
- DoCommand() : command.cpp , command_func.h
- DoCommandFlag : command_type.h
- DoCommandP() : command_func.h , command.cpp , command_func.h
- DoCreateTown() : town_cmd.cpp
- DoDrawString() : gfx.cpp , gfx_func.h
- DoDrawStringCentered() : gfx.cpp , gfx_func.h
- DoDrawStringTruncated() : gfx.cpp , gfx_func.h
- DoDryUp() : water_cmd.cpp
- DoExitSave() : saveload.cpp , saveload.h
- DoFloodTile() : water_cmd.cpp , water.h
- DoPlaceMoreTrees() : tree_cmd.cpp
- DoSelectCompanyManagerFace() : company_gui.cpp
- DoShowCompanyFinances() : company_gui.cpp
- DoStartupNewCompany() : company_cmd.cpp , openttd.cpp , afterload.cpp
- DoTrainPathfind() : train_cmd.cpp
- DrawAircraftDetails() : aircraft_gui.cpp , vehicle_gui.cpp
- DrawArrowButtons() : gui.h , settings_gui.cpp
- DrawAutorailSelection() : viewport.cpp
- DrawBox() : gfx.cpp , gfx_func.h
- DrawBridgePillars() : tunnelbridge_cmd.cpp
- DrawBridgeTramBits() : tunnelbridge_cmd.cpp
- DrawCanalWater() : water_cmd.cpp
- DrawCargoIcons() : station_gui.cpp
- DrawCatenary() : elrail.cpp , elrail_func.h
- DrawCatenaryOnTunnel() : elrail.cpp , elrail_func.h
- DrawCatenaryRailway() : elrail.cpp
- DrawCharCentered() : gfx.cpp
- DrawCompanyManagerFace() : company_gui.cpp , company_manager_face.h
- DrawCompanyOwnerText() : company_gui.cpp
- DrawCompanyVehiclesAmount() : company_gui.cpp
- DrawDirtyBlocks() : gfx.cpp , gfx_func.h
- DrawEngineList() : build_vehicle_gui.cpp , autoreplace_gui.cpp
- DrawFoundation() : landscape.h , landscape.cpp
- DrawFrameRect() : widget.cpp , window_gui.h
- DrawGroundSprite() : viewport.cpp , viewport_func.h
- DrawGroundSpriteAt() : viewport_func.h , viewport.cpp
- DrawNewsString() : news_gui.cpp
- DrawOverlappedWindow() : window.cpp
- DrawOverlappedWindowForAll() : window.cpp , gfx_func.h
- DrawRoadBits() : road_cmd.cpp
- DrawRoadDetail() : road_cmd.cpp
- DrawSeaWater() : water_cmd.cpp
- DrawSelectionSprite() : viewport.cpp
- DrawShipDetails() : vehicle_gui.cpp , ship_gui.cpp
- DrawSmallMapStuff() : smallmap_gui.cpp
- DrawSprite() : gfx.cpp , gfx_func.h
- DrawStationCoverageAreaText() : station_gui.h , misc_gui.cpp
- DrawStationTile() : newgrf_station.cpp , newgrf_station.h
- DrawString() : gfx_func.h , gfx.cpp
- DrawStringCentered() : gfx.cpp , gfx_func.h
- DrawStringCenteredTruncated() : gfx.cpp , gfx_func.h
- DrawStringCenterUnderline() : gfx.cpp , gfx_func.h
- DrawStringCenterUnderlineTruncated() : gfx_func.h , gfx.cpp
- DrawStringMultiCenter() : gfx_func.h , gfx.cpp
- DrawStringRightAligned() : gfx.cpp , gfx_func.h
- DrawStringRightAlignedTruncated() : gfx_func.h , gfx.cpp
- DrawStringRightAlignedUnderline() : gfx_func.h , gfx.cpp
- DrawStringTruncated() : gfx_func.h , gfx.cpp
- DrawTile_Road() : road_cmd.cpp
- DrawTile_Town() : town_cmd.cpp
- DrawTile_TunnelBridge() : tunnelbridge_cmd.cpp
- DrawTileProc : tile_cmd.h
- DrawTileSelection() : viewport.cpp
- DrawTileSelectionRect() : viewport.cpp
- DrawTrackBits() : rail_cmd.cpp
- DrawTrackFence_NS_1() : rail_cmd.cpp
- DrawTrackFence_NS_2() : rail_cmd.cpp
- DrawTrackFence_WE_1() : rail_cmd.cpp
- DrawTrackFence_WE_2() : rail_cmd.cpp
- DrawTramCatenary() : road_cmd.cpp , road_internal.h
- DrawVehicleProfitButton() : vehicle_gui.cpp , vehicle_gui.h
- DrawVehiclePurchaseInfo() : build_vehicle_gui.cpp , vehicle_gui.h
- DrawVehicleRefitWindow() : vehicle_gui.cpp
- DrawWaypointSprite() : waypoint.cpp , waypoint.h
- DRD_BOTH : road_map.h
- DRD_NONE : road_map.h
- DRD_NORTHBOUND : road_map.h
- DRD_SOUTHBOUND : road_map.h
- DropDownList : dropdown_type.h
- DSGA_OP_ADD : newgrf_spritegroup.h
- DSGA_OP_AND : newgrf_spritegroup.h
- DSGA_OP_MUL : newgrf_spritegroup.h
- DSGA_OP_OR : newgrf_spritegroup.h
- DSGA_OP_ROR : newgrf_spritegroup.h
- DSGA_OP_RST : newgrf_spritegroup.h
- DSGA_OP_SCMP : newgrf_spritegroup.h
- DSGA_OP_SDIV : newgrf_spritegroup.h
- DSGA_OP_SMAX : newgrf_spritegroup.h
- DSGA_OP_SMIN : newgrf_spritegroup.h
- DSGA_OP_SMOD : newgrf_spritegroup.h
- DSGA_OP_STO : newgrf_spritegroup.h
- DSGA_OP_STOP : newgrf_spritegroup.h
- DSGA_OP_SUB : newgrf_spritegroup.h
- DSGA_OP_UCMP : newgrf_spritegroup.h
- DSGA_OP_UDIV : newgrf_spritegroup.h
- DSGA_OP_UMAX : newgrf_spritegroup.h
- DSGA_OP_UMIN : newgrf_spritegroup.h
- DSGA_OP_UMOD : newgrf_spritegroup.h
- DSGA_OP_XOR : newgrf_spritegroup.h
- DTW_BEGIN : dock_gui.cpp
- DTW_BUILD_AQUEDUCT : dock_gui.cpp
- DTW_BUOY : dock_gui.cpp
- DTW_BUTTONS_BEGIN : dock_gui.cpp
- DTW_CANAL : dock_gui.cpp
- DTW_CAPTION : dock_gui.cpp
- DTW_CLOSEBOX : dock_gui.cpp
- DTW_DEMOLISH : dock_gui.cpp
- DTW_DEPOT : dock_gui.cpp
- DTW_END : dock_gui.cpp
- DTW_LOCK : dock_gui.cpp
- DTW_RIVER : dock_gui.cpp
- DTW_SEPERATOR : dock_gui.cpp
- DTW_STATION : dock_gui.cpp
- DTW_STICKY : dock_gui.cpp
- DynamicPlaceIndustriesWidgets : industry_gui.cpp