Here is a list of all documented struct and union fields with links to the struct/union documentation for each field:

### - i -

- IConsoleLine() : IConsoleLine
- id : ContentInfo , NamePart , ChunkHandler , AllowedSubtags , ThreadObject_Win32
- ident : LanguagePackHeader , GRFConfig
- IDENT : LanguagePackHeader
- IDLE_TIMEOUT : ClientNetworkContentSocketHandler
- IL_MULTIPLIER : IndustryViewWindow
- IL_NONE : IndustryViewWindow
- IL_RATE1 : IndustryViewWindow
- IL_RATE2 : IndustryViewWindow
- image : ParentSpriteToDraw
- image_1 : DrawIndustryAnimationStruct
- image_2 : DrawIndustryAnimationStruct
- image_3 : DrawIndustryAnimationStruct
- image_override : DisasterVehicle
- Import() : AILibrary
- ImportLibrary() : AI , AIScanner
- improved_load : OrderSettings
- in_use : Livery
- in_window : CursorVars
- inaugurated_year : CompanyProperties , NetworkCompanyInfo
- IncIndustryTypeCount() : Industry
- Include() : SmallVector< T, S > , CBinaryHeapT< T >
- income : NetworkCompanyInfo
- incoming_cargo_waiting : Industry
- incoming_queue : NetworkGameSocketHandler
- IncreaseDoCommandCosts() : AIObject
- IncrementAutoOrderIndex() : Vehicle
- IncrementRealOrderIndex() : Vehicle
- IncTypeCount() : Object
- ind_cargo : IndustryCargoesWindow
- ind_type : CargoesField
- index : Pool< Titem, Tindex, Tgrowth_step, Tmax_size, Tcache, Tzero >::PoolItem< Tpool > , BuildIndustryWindow , SettingEntrySetting , VehicleListIdentifier , NWidgetCore , NWidgetStacked , NWidgetMatrix , NWidgetPartWidget
- Index() : CargoSpec , ObjectSpec
- indtype : Station
- indtypes : StationNameInformation
- industries_near : Station
- industry : CargoesField
- industry_daily_change_counter : Economy
- industry_daily_increment : Economy
- industry_density : DifficultySettings
- INDUSTRY_LINE_COLOUR : CargoesField
- INDUSTRY_MIN_NUMBER_OF_COLUMNS : SmallMapWindow
- industry_platform : ConstructionSettings
- industry_width : CargoesField
- IndustryNameSorter() : IndustryDirectoryWindow
- IndustryProductionSorter() : IndustryDirectoryWindow
- IndustryTransportedCargoSorter() : IndustryDirectoryWindow
- INDUSTRYTYPE_TOWN : AIIndustryType
- INDUSTRYTYPE_UNKNOWN : AIIndustryType
- IndustryTypeSorter() : IndustryDirectoryWindow
- inf : NWidgetNewGRFDisplay
- infl_amount : Economy
- infl_amount_pr : Economy
- inflation : EconomySettings
- inflation_payment : Economy
- inflation_prices : Economy
- info : AIConfig , NetworkGameSocketHandler , NetworkGameList , GRFConfig
- Info() : AILog
- info_height : IndustryViewWindow , BuildObjectWindow
- info_view : ResolverObject
- InfoLine : IndustryViewWindow
- information_width : RefitWindow
- infos : ClientNetworkContentSocketHandler
- ini_set : BaseMedia< Tbase_set >
- IniFile() : IniFile
- IniGroup() : IniGroup
- IniItem() : IniItem
- Init() : ByteBlob , AyStar , BinaryHeap , Hash , SettingEntry , SettingsPage
- init_load : SaveLoadFormat
- init_proc : Disaster
- init_write : SaveLoadFormat
- InitEmpty() : ByteBlob
- initial_city_size : EconomySettings
- initial_interest : DifficultySettings
- initial_random_bits : ResolverObject
- InitialiseCrashLog() : CrashLog
- Initialize() : AI , OrderList
- initialized : AIList
- InitializeData() : Window
- InitializeLayout() : Town
- InitializePositionSize() : Window
- InitializeViewport() : NWidgetViewport
- InitNested() : Window
- input_cargo_multiplier : IndustrySpec
- Insert() : SmallMap< T, U, S >
- InsertClosedNode() : CNodeList_HashTableT< Titem_, Thash_bits_open_, Thash_bits_closed_ >
- InsertConditionalOrder() : AIOrder
- InsertDefaults() : NewGRFClass< Tspec, Tid, Tmax >
- InsertEvent() : AIEventController
- InsertOpenNode() : CNodeList_HashTableT< Titem_, Thash_bits_open_, Thash_bits_closed_ >
- InsertOrder() : AIOrder
- InsertOrderAt() : OrderList
- instance : AIInstance
- instant_close : DropdownWindow
- INTER_COLUMN_SPACING : NWidgetNewGRFDisplay
- INTER_LIST_SPACING : NWidgetNewGRFDisplay
- interest_rate : Economy
- internal_id : EngineIDMapping
- Intersects() : TileArea
- interval : SettingDescBase
- introduces_railtypes : RailtypeInfo
- introduction_date : ObjectSpec , RailtypeInfo
- introduction_required_railtypes : RailtypeInfo
- INVALID : ContentInfo
- invalid : MakeEnumPropsT< Tenum_t, Tstorage_t, Tbegin, Tend, Tinvalid, Tnum_bits > , TinyEnumT< Tenum_t >
- invalid_ID : OverrideManagerBase
- InvalidateAllFrom() : CargoPacket
- InvalidateCache() : CargoList< Tinst > , VehicleCargoList
- InvalidateData() : Window
- InvalidateDimensionCache() : NWidgetLeaf
- InvalidateNewGRFCache() : Vehicle
- InvalidateNewGRFCacheOfChain() : Vehicle
- is_ai : CompanyProperties
- is_dead : AIInstance
- is_female : SelectCompanyManagerFaceWindow
- is_freight : CargoSpec
- is_moust_male : SelectCompanyManagerFaceWindow
- is_random_ai : AIConfig
- is_save_data_on_stack : AIInstance
- is_started : AIInstance
- is_vertical : Scrollbar
- IsActionAvailable() : AITown
- IsAirportInformationAvailable() : AIAirport
- IsAirportTile() : AIAirport
- IsAnyStationTileReserved() : CYapfCostRailT< Types >
- IsArticulated() : AIEngine , AIVehicle
- IsArticulatedPart() : Vehicle
- IsAvailable() : AirportSpec , ObjectSpec
- IsAwarded() : AISubsidy , Subsidy
- IsBridgeTile() : AIBridge
- IsBuildable() : AIEngine , AITile
- IsBuildableRectangle() : AITile
- IsBuiltOnWater() : AIIndustry , AIIndustryType
- IsBuoyTile() : AIMarine
- IsBus() : RoadVehicle
- IsButton() : NWidgetToolbarContainer
- IsCanalTile() : AIMarine
- IsCargoAccepted() : AIIndustry
- IsCity() : AITown
- IsCoastTile() : AITile
- IsCompletelyTimetabled() : Order
- IsCompleteTimetable() : OrderList
- IsConditionalOrder() : AIOrder
- IsConnected() : NetworkTCPSocketHandler , NetworkHTTPSocketHandler , ClientNetworkGameSocketHandler
- isConnecting : ClientNetworkContentSocketHandler
- IsCurrentOrderPartOfOrderList() : AIOrder
- IsDead() : AIInstance
- IsDescSortOrder() : GUIList< T, F >
- IsDesertTile() : AITile
- IsDisabled() : NWidgetCore
- IsDisabledVehicleType() : AIGameSettings
- IsDockTile() : AIMarine
- IsDraggingDiagonal() : TileHighlightData
- IsDriveThroughRoadStationTile() : AIRoad
- IsDriveThroughRoadStopContinuation() : RoadStop
- IsEditable() : AIConfigWindow
- IsEmpty() : SmallSet< Tdir, items > , AIList , SmallArray< T, B, N > , CBinaryHeapT< T > , ByteBlob , FixedSizeArray< T, C > , NWidgetContainer
- IsEnabled() : Engine
- IsEnd() : AIListSorterValueAscending , AIList , AIListSorter , AIListSorterValueDescending , AIListSorterItemAscending , AIListSorterItemDescending
- IsEngine() : GroundVehicle< T, Type >
- IsEngineCountable() : Vehicle
- IsEntranceBusy() : RoadStop
- IsEventWaiting() : AIEventController
- IsExpected() : SpecializedStation< T, Tis_waypoint >
- IsFamily() : NetworkAddress
- IsFarmTile() : AITile
- IsFilterEnabled() : GUIList< T, F >
- IsFreeBay() : RoadStop
- IsFreeWagon() : GroundVehicle< T, Type >
- IsFreight() : AICargo
- IsFrontEngine() : Vehicle
- IsFull() : SmallSet< Tdir, items > , SmallArray< T, B, N > , CBinaryHeapT< T > , FixedSizeArray< T, C >
- IsGotoDepotOrder() : AIOrder
- IsGotoStationOrder() : AIOrder
- IsGotoWaypointOrder() : AIOrder
- IsGroundVehicle() : Engine , Vehicle
- IsHalftileSlope() : AITile
- IsHangarTile() : AIAirport
- IsHumanID() : Company
- IsIn() : SmallSet< Tdir, items >
- IsInDepot() : AIVehicle , Aircraft , Ship , Train , Vehicle , RoadVehicle
- IsInNetmask() : NetworkAddress
- IsInspectable() : NIHTown , NIHHouse , NIHRailType , NIHObject , NIHelper , NIHVehicle , NIHStation , NIHIndustryTile , NIHAirportTile , NIHIndustry
- IsInUse() : BaseStation
- IsLevelCrossingTile() : AIRail
- IsLockTile() : AIMarine
- IsLowered() : NWidgetCore
- IsMine() : AICompany
- IsMultiheaded() : GroundVehicle< T, Type >
- IsNewGRFInspectable() : IndustryViewWindow , LandInfoWindow , VehicleViewWindow , Window
- IsNormalAircraft() : Aircraft
- IsNull() : CCountedPtr< Tcls_ >
- isocode : LanguagePackHeader
- IsOfType() : Waypoint , Depot
- IsOpenTTDBaseGRF() : GRFConfig
- IsOrderListShared() : Vehicle
- IsPrimaryVehicle() : RoadVehicle , Ship , Train , Aircraft , Vehicle
- IsRailDepotTile() : AIRail
- IsRailStationTile() : AIRail
- IsRailTile() : AIRail
- IsRailTypeAvailable() : AIRail
- IsRailWaypointTile() : AIRail
- IsRandomAI() : AIConfig
- IsRawIndustry() : IndustrySpec , AIIndustryType
- IsRearDualheaded() : GroundVehicle< T, Type >
- IsRefit() : Order
- IsResolved() : NetworkAddress
- IsRoadDepotTile() : AIRoad
- IsRoadStationTile() : AIRoad
- IsRoadTile() : AIRoad
- IsRoadTypeAvailable() : AIRoad
- IsRockTile() : AITile
- IsRoughTile() : AITile
- IsSelected() : ContentInfo
- IsShaded() : Window
- IsShared() : OrderList
- IsSingleTile() : Waypoint
- IsSnowTile() : AITile
- IsSongPlaying() : MusicDriver_QtMidi
- IsSortable() : GUIList< T, F >
- IsStationTile() : AITile
- IsSteepSlope() : AITile
- IsStoppedInDepot() : Train , Vehicle , AIVehicle , RoadVehicle
- IsSuspended() : Squirrel
- IsTunnelTile() : AITunnel
- IsType() : Order
- IsValid() : LanguagePackHeader , CargoSpec , Backup< T > , ContentInfo , AIGameSettings
- IsValidAiID() : Company
- IsValidAirportType() : AIAirport
- IsValidBaseStation() : AIBaseStation
- IsValidBridge() : AIBridge
- IsValidCargo() : AICargo
- IsValidConditionalOrder() : AIOrder
- IsValidEngine() : AIEngine
- IsValidGroup() : AIGroup
- IsValidHumanID() : Company
- IsValidID() : Pool< Titem, Tindex, Tgrowth_step, Tmax_size, Tcache, Tzero > , SpecializedVehicle< T, Type > , Pool< Titem, Tindex, Tgrowth_step, Tmax_size, Tcache, Tzero >::PoolItem< Tpool > , SpecializedStation< T, Tis_waypoint >
- IsValidIndustry() : AIIndustry
- IsValidIndustryType() : AIIndustryType
- IsValidSign() : AISign
- IsValidStation() : AIStation
- IsValidSubsidy() : AISubsidy
- IsValidTile() : AIMap
- IsValidTown() : AITown
- IsValidVehicle() : AIVehicle
- IsValidVehicleOrder() : AIOrder
- IsValidWaypoint() : AIWaypoint
- IsVehicleInSharedOrdersList() : OrderList
- IsVehicleServiceIntervalEnabled() : VehicleDetailsWindow
- IsVertical() : Scrollbar
- IsVisible() : Scrollbar
- IsVoidOrder() : AIOrder
- IsWagon() : GroundVehicle< T, Type > , AIEngine
- IsWaterDepotTile() : AIMarine
- IsWaterTile() : AITile
- IsWidgetDisabled() : Window
- IsWidgetFocused() : Window
- IsWidgetGloballyFocused() : Window
- IsWidgetLowered() : Window
- IsWidgetVisible() : NWidgetServerListHeader
- IsWithinTownInfluence() : AIStation , AITile , AITown
- item : IniGroup
- items : AIList , FixedSizeArray< T, C >::ArrayHeader , ByteBlob::BlobHeader , Pool< Titem, Tindex, Tgrowth_step, Tmax_size, Tcache, Tzero >
- Items() : SmallSet< Tdir, items >
- items : SmallVector< T, S > , CBinaryHeapT< T >
- Iterator : CargoList< Tinst >