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

### - h -

- H2I : tgp.cpp
- HalftileFoundation() : slope_func.h
- HalftileSlope() : slope_func.h
- HaltLift() : town_map.h
- HandleAircraftEnterHangar() : aircraft.h , aircraft_cmd.cpp
- HandleAutoscroll() : window.cpp
- HandleAutoSignalPlacement() : rail_gui.cpp
- HandleCtrlChanged() : gfx_func.h , window.cpp
- HandleEditBoxResult : querystring_gui.h
- HandleGeneratingWorldAbortion() : genworld.cpp , genworld.h
- HandleInvalidSpriteRequest() : spritecache.cpp
- HandleKeypress() : window.cpp , gfx_func.h
- HandleMouseEvents() : gfx_func.h , window.cpp
- HandleOldDiffCustom() : settings.cpp
- HandlePlacePushButton() : main_gui.cpp , tilehighlight_func.h
- HandleSavegameLoadCrash() : afterload.cpp
- HandleScrollbarHittest() : widget.cpp
- HandleZoomMessage() : viewport.cpp , viewport_func.h
- HasBit() : bitmath_func.hpp
- HASBITS : bitmath_func.hpp
- HasBridgeFlatRamp() : bridge.h , tunnelbridge_cmd.cpp
- HasCatenary() : elrail_func.h
- HasCatenaryDrawn() : elrail_func.h
- Hash_Delete() : queue.cpp , queue.h
- Hash_FindNode() : queue.cpp
- Hash_Get() : queue.cpp , queue.h
- Hash_HashProc : queue.h
- Hash_Set() : queue.cpp , queue.h
- Hash_Size() : queue.cpp , queue.h
- HasOnewaySignalBlockingTrackdir() : rail_map.h
- HasPbsSignalOnTrackdir() : rail_map.h
- HasPowerOnRail() : rail.h
- HasRailtypeAvail() : rail.cpp , rail.h
- HasReservedTracks() : pbs.h
- HasRoadTypesAvail() : road.cpp , road_func.h
- HasSignalOnTrack() : rail_map.h
- HasSignalOnTrackdir() : rail_map.h
- HasSignals() : rail_map.h
- HasSlopeHighestCorner() : slope_func.h
- HasStationInUse() : station_cmd.cpp , station_func.h
- HasTownOwnedRoad() : road_map.h
- HasTrack() : rail_map.h
- HasTunnelBridgeSnowOrDesert() : tunnelbridge_map.h
- HasVehicleOnPos() : vehicle.cpp , vehicle_func.h
- HasVehicleOnPosXY() : vehicle.cpp , vehicle_func.h
- HasVehicleOnTunnelBridge() : vehicle_func.h , vehicle.cpp
- HeapifyDown() : pathfind.cpp
- HeapifyUp() : pathfind.cpp
- height_t : tgp.cpp
- HEIGHTMAP_DIR : fileio_type.h
- HeightMapAdjustWaterLevel() : tgp.cpp
- HeightMapCoastLines() : tgp.cpp
- HeightMapGenerate() : tgp.cpp
- HeightMapGetMinMaxAvg() : tgp.cpp
- HeightMapMakeHistogram() : tgp.cpp
- HeightMapNormalize() : tgp.cpp
- HeightMapSineTransform() : tgp.cpp
- HeightMapSmoothCoastInDirection() : tgp.cpp
- HeightMapSmoothCoasts() : tgp.cpp
- HeightMapSmoothSlopes() : tgp.cpp
- HelicopterRotorStates : aircraft_cmd.cpp
- HELIPAD_GROUP_block : airport.h
- HideDropDownMenu() : dropdown.cpp , dropdown_func.h
- HideVitalWindows() : window.cpp , window_func.h
- HighestSnowLine() : landscape.cpp , landscape.h
- HighLightStyle : tilehighlight_type.h
- HighScoreSorter() : highscore.cpp
- HM_CLOCKWISE : heightmap.h
- HM_COUNTER_CLOCKWISE : heightmap.h
- HouseCallbackMask : newgrf_callbacks.h
- HouseExtraFlags : town.h
- HouseGetVariable() : newgrf_house.cpp
- HouseZones : town.h
- HSQOBJECT : ai_types.hpp
- HSQUIRRELVM : ai_types.hpp
- HT_DIR_HL : tilehighlight_type.h
- HT_DIR_HU : tilehighlight_type.h
- HT_DIR_MASK : tilehighlight_type.h
- HT_DIR_VL : tilehighlight_type.h
- HT_DIR_VR : tilehighlight_type.h
- HT_DIR_X : tilehighlight_type.h
- HT_DIR_Y : tilehighlight_type.h
- HT_DRAG_MASK : tilehighlight_type.h
- HT_LINE : tilehighlight_type.h
- HT_RAIL : tilehighlight_type.h
- HZ_NOZNS : town.h
- HZ_SUBARTC_ABOVE : town.h
- HZ_SUBARTC_BELOW : town.h
- HZ_SUBTROPIC : town.h
- HZ_TEMP : town.h
- HZ_TOYLND : town.h
- HZ_ZON1 : town.h
- HZ_ZON5 : town.h
- HZ_ZONALL : town.h