[freerdp,api] mark function pointers [[nodiscard]]

2026-04-14 00:14:11 +09:00 · 2026-02-15 22:45:20 +01:00
parent 399d92f26e
commit 6a1cc0f031
59 changed files with 847 additions and 813 deletions
--- a/channels/rdpecam/client/camera_device_enum_main.c
+++ b/channels/rdpecam/client/camera_device_enum_main.c
@@ -169,9 +169,7 @@ static UINT ecam_ihal_device_added_callback(CameraPlugin* ecam, GENERIC_CHANNEL_
 */
 static UINT ecam_enumerate_devices(CameraPlugin* ecam, GENERIC_CHANNEL_CALLBACK* hchannel)
 {
-	ecam->ihal->Enumerate(ecam->ihal, ecam_ihal_device_added_callback, ecam, hchannel);
-
-	return CHANNEL_RC_OK;
+	return ecam->ihal->Enumerate(ecam->ihal, ecam_ihal_device_added_callback, ecam, hchannel);
 }

 /**
--- a/include/freerdp/altsec.h
+++ b/include/freerdp/altsec.h
@@ -185,20 +185,20 @@ extern "C"
 		rdpContext* context;     /* 0 */
 		UINT32 paddingA[16 - 1]; /* 1 */

-		pCreateOffscreenBitmap CreateOffscreenBitmap; /* 16 */
-		pSwitchSurface SwitchSurface;                 /* 17 */
-		pCreateNineGridBitmap CreateNineGridBitmap;   /* 18 */
-		pFrameMarker FrameMarker;                     /* 19 */
-		pStreamBitmapFirst StreamBitmapFirst;         /* 20 */
-		pStreamBitmapNext StreamBitmapNext;           /* 21 */
-		pDrawGdiPlusFirst DrawGdiPlusFirst;           /* 22 */
-		pDrawGdiPlusNext DrawGdiPlusNext;             /* 23 */
-		pDrawGdiPlusEnd DrawGdiPlusEnd;               /* 24 */
-		pDrawGdiPlusCacheFirst DrawGdiPlusCacheFirst; /* 25 */
-		pDrawGdiPlusCacheNext DrawGdiPlusCacheNext;   /* 26 */
-		pDrawGdiPlusCacheEnd DrawGdiPlusCacheEnd;     /* 27 */
-		/* Statistics callback */
-		pDrawOrderInfo DrawOrderInfo; /* 28 */
+		WINPR_ATTR_NODISCARD pCreateOffscreenBitmap CreateOffscreenBitmap; /* 16 */
+		WINPR_ATTR_NODISCARD pSwitchSurface SwitchSurface;                 /* 17 */
+		WINPR_ATTR_NODISCARD pCreateNineGridBitmap CreateNineGridBitmap;   /* 18 */
+		WINPR_ATTR_NODISCARD pFrameMarker FrameMarker;                     /* 19 */
+		WINPR_ATTR_NODISCARD pStreamBitmapFirst StreamBitmapFirst;         /* 20 */
+		WINPR_ATTR_NODISCARD pStreamBitmapNext StreamBitmapNext;           /* 21 */
+		WINPR_ATTR_NODISCARD pDrawGdiPlusFirst DrawGdiPlusFirst;           /* 22 */
+		WINPR_ATTR_NODISCARD pDrawGdiPlusNext DrawGdiPlusNext;             /* 23 */
+		WINPR_ATTR_NODISCARD pDrawGdiPlusEnd DrawGdiPlusEnd;               /* 24 */
+		WINPR_ATTR_NODISCARD pDrawGdiPlusCacheFirst DrawGdiPlusCacheFirst; /* 25 */
+		WINPR_ATTR_NODISCARD pDrawGdiPlusCacheNext DrawGdiPlusCacheNext;   /* 26 */
+		WINPR_ATTR_NODISCARD pDrawGdiPlusCacheEnd DrawGdiPlusCacheEnd;     /* 27 */
+		                                                                   /* Statistics callback */
+		WINPR_ATTR_NODISCARD pDrawOrderInfo DrawOrderInfo;                 /* 28 */
 		UINT32 paddingB[32 - 29];     /* 29 */
 	};
 	typedef struct rdp_altsec_update rdpAltSecUpdate;
--- a/include/freerdp/autodetect.h
+++ b/include/freerdp/autodetect.h
@@ -120,19 +120,23 @@ extern "C"
 		ALIGN64 wLog* log;                      /* 11 */
 		UINT64 paddingA[16 - 12];               /* 12 */

-		ALIGN64 pRTTMeasureRequest RTTMeasureRequest;                       /* 16 */
-		ALIGN64 pRTTMeasureResponse RTTMeasureResponse;                     /* 17 */
-		ALIGN64 pBandwidthMeasureStart BandwidthMeasureStart;               /* 18 */
-		ALIGN64 pBandwidthMeasurePayload BandwidthMeasurePayload;           /* 19 */
-		ALIGN64 pBandwidthMeasureStop BandwidthMeasureStop;                 /* 20 */
-		ALIGN64 pBandwidthMeasureResults BandwidthMeasureResults;           /* 21 */
-		ALIGN64 pNetworkCharacteristicsResult NetworkCharacteristicsResult; /* 22 */
-		ALIGN64 pClientBandwidthMeasureResult ClientBandwidthMeasureResult; /* 23 */
-		ALIGN64 pNetworkCharacteristicsSync NetworkCharacteristicsSync;     /* 24 */
-		ALIGN64 pRxTxReceived RequestReceived;                              /* 25 */
-		ALIGN64 pRxTxReceived ResponseReceived;                             /* 26 */
-		ALIGN64 pOnConnectTimeAutoDetect OnConnectTimeAutoDetectBegin;      /* 27 */
-		ALIGN64 pOnConnectTimeAutoDetect OnConnectTimeAutoDetectProgress;   /* 28 */
+		ALIGN64 WINPR_ATTR_NODISCARD pRTTMeasureRequest RTTMeasureRequest;             /* 16 */
+		ALIGN64 WINPR_ATTR_NODISCARD pRTTMeasureResponse RTTMeasureResponse;           /* 17 */
+		ALIGN64 WINPR_ATTR_NODISCARD pBandwidthMeasureStart BandwidthMeasureStart;     /* 18 */
+		ALIGN64 WINPR_ATTR_NODISCARD pBandwidthMeasurePayload BandwidthMeasurePayload; /* 19 */
+		ALIGN64 WINPR_ATTR_NODISCARD pBandwidthMeasureStop BandwidthMeasureStop;       /* 20 */
+		ALIGN64 WINPR_ATTR_NODISCARD pBandwidthMeasureResults BandwidthMeasureResults; /* 21 */
+		ALIGN64 WINPR_ATTR_NODISCARD pNetworkCharacteristicsResult
+		    NetworkCharacteristicsResult; /* 22 */
+		ALIGN64 WINPR_ATTR_NODISCARD pClientBandwidthMeasureResult
+		    ClientBandwidthMeasureResult; /* 23 */
+		ALIGN64 WINPR_ATTR_NODISCARD pNetworkCharacteristicsSync
+		    NetworkCharacteristicsSync;                                                     /* 24 */
+		ALIGN64 WINPR_ATTR_NODISCARD pRxTxReceived RequestReceived;                         /* 25 */
+		ALIGN64 WINPR_ATTR_NODISCARD pRxTxReceived ResponseReceived;                        /* 26 */
+		ALIGN64 WINPR_ATTR_NODISCARD pOnConnectTimeAutoDetect OnConnectTimeAutoDetectBegin; /* 27 */
+		ALIGN64 WINPR_ATTR_NODISCARD pOnConnectTimeAutoDetect
+		    OnConnectTimeAutoDetectProgress;                                /* 28 */
 		UINT64 paddingB[32 - 29];                                           /* 29 */
 	};
 	FREERDP_API rdpAutoDetect* autodetect_get(rdpContext* context);
--- a/include/freerdp/channels/rdpdr.h
+++ b/include/freerdp/channels/rdpdr.h
@@ -325,7 +325,7 @@ typedef struct S_IRP IRP;
 typedef struct S_DEVMAN DEVMAN;

 typedef UINT (*pcCustomComponentRequest)(DEVICE* device, UINT16 component, UINT16 packetId,
-                                         wStream* s);
+	                                     wStream* s);
 typedef UINT (*pcIRPRequest)(DEVICE* device, IRP* irp);
 typedef UINT (*pcInitDevice)(DEVICE* device);
 typedef UINT (*pcFreeDevice)(DEVICE* device);
@@ -338,9 +338,9 @@ struct S_DEVICE
 	const char* name;
 	wStream* data;

-	pcCustomComponentRequest CustomComponentRequest;
-	pcIRPRequest IRPRequest;
-	pcInitDevice Init;
+	WINPR_ATTR_NODISCARD pcCustomComponentRequest CustomComponentRequest;
+	WINPR_ATTR_NODISCARD pcIRPRequest IRPRequest;
+	WINPR_ATTR_NODISCARD pcInitDevice Init;
 	pcFreeDevice Free;
 };

@@ -361,7 +361,7 @@ struct S_IRP
 	NTSTATUS IoStatus;
 	wStream* output;

-	pcIRPResponse Complete;
+	WINPR_ATTR_NODISCARD pcIRPResponse Complete;
 	pcIRPResponse Discard;

 	HANDLE thread;
@@ -381,7 +381,7 @@ typedef struct
 {
 	DEVMAN* devman;

-	pcRegisterDevice RegisterDevice;
+	WINPR_ATTR_NODISCARD pcRegisterDevice RegisterDevice;
 	RDPDR_DEVICE* device;
 	rdpContext* rdpcontext;
 } DEVICE_SERVICE_ENTRY_POINTS;
--- a/include/freerdp/client.h
+++ b/include/freerdp/client.h
@@ -72,14 +72,14 @@ extern "C"

 		rdpSettings* settings;

-		pRdpGlobalInit GlobalInit;
+		WINPR_ATTR_NODISCARD pRdpGlobalInit GlobalInit;
 		pRdpGlobalUninit GlobalUninit;

 		DWORD ContextSize;
-		pRdpClientNew ClientNew;
+		WINPR_ATTR_NODISCARD pRdpClientNew ClientNew;
 		pRdpClientFree ClientFree;

-		pRdpClientStart ClientStart;
+		WINPR_ATTR_NODISCARD pRdpClientStart ClientStart;
 		pRdpClientStop ClientStop;
 	};

--- a/include/freerdp/client/ainput.h
+++ b/include/freerdp/client/ainput.h
@@ -38,7 +38,7 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcAInputSendInputEvent AInputSendInputEvent;
+		WINPR_ATTR_NODISCARD pcAInputSendInputEvent AInputSendInputEvent;
 	};

 #ifdef __cplusplus
--- a/include/freerdp/client/audin.h
+++ b/include/freerdp/client/audin.h
@@ -43,25 +43,27 @@ extern "C"
 	typedef struct s_IAudinDevice IAudinDevice;
 	struct s_IAudinDevice
 	{
-		UINT (*Open)(IAudinDevice* devplugin, AudinReceive receive, void* userData);
-		BOOL (*FormatSupported)(IAudinDevice* devplugin, const AUDIO_FORMAT* format);
-		UINT(*SetFormat)
-		(IAudinDevice* devplugin, const AUDIO_FORMAT* format, UINT32 FramesPerPacket);
-		UINT (*Close)(IAudinDevice* devplugin);
-		UINT (*Free)(IAudinDevice* devplugin);
+		WINPR_ATTR_NODISCARD UINT (*Open)(IAudinDevice* devplugin, AudinReceive receive,
+		                                  void* userData);
+		WINPR_ATTR_NODISCARD BOOL (*FormatSupported)(IAudinDevice* devplugin,
+		                                             const AUDIO_FORMAT* format);
+		WINPR_ATTR_NODISCARD UINT (*SetFormat)(IAudinDevice* devplugin, const AUDIO_FORMAT* format,
+		                                       UINT32 FramesPerPacket);
+		WINPR_ATTR_NODISCARD UINT (*Close)(IAudinDevice* devplugin);
+		WINPR_ATTR_NODISCARD UINT (*Free)(IAudinDevice* devplugin);
 	};

 #define AUDIN_DEVICE_EXPORT_FUNC_NAME "freerdp_audin_client_subsystem_entry"

-typedef UINT (*PREGISTERAUDINDEVICE)(IWTSPlugin* plugin, IAudinDevice* device);
+	typedef UINT (*PREGISTERAUDINDEVICE)(IWTSPlugin* plugin, IAudinDevice* device);

-typedef struct
-{
-	IWTSPlugin* plugin;
-	PREGISTERAUDINDEVICE pRegisterAudinDevice;
-	const ADDIN_ARGV* args;
-	rdpContext* rdpcontext;
-} FREERDP_AUDIN_DEVICE_ENTRY_POINTS;
+	typedef struct
+	{
+		IWTSPlugin* plugin;
+		WINPR_ATTR_NODISCARD PREGISTERAUDINDEVICE pRegisterAudinDevice;
+		const ADDIN_ARGV* args;
+		rdpContext* rdpcontext;
+	} FREERDP_AUDIN_DEVICE_ENTRY_POINTS;
 typedef FREERDP_AUDIN_DEVICE_ENTRY_POINTS* PFREERDP_AUDIN_DEVICE_ENTRY_POINTS;

 typedef UINT(VCAPITYPE* PFREERDP_AUDIN_DEVICE_ENTRY)(
--- a/include/freerdp/client/cliprdr.h
+++ b/include/freerdp/client/cliprdr.h
@@ -85,26 +85,26 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcCliprdrServerCapabilities ServerCapabilities;
-		pcCliprdrClientCapabilities ClientCapabilities;
-		pcCliprdrMonitorReady MonitorReady;
-		pcCliprdrTempDirectory TempDirectory;
-		pcCliprdrClientFormatList ClientFormatList;
-		pcCliprdrServerFormatList ServerFormatList;
-		pcCliprdrClientFormatListResponse ClientFormatListResponse;
-		pcCliprdrServerFormatListResponse ServerFormatListResponse;
-		pcCliprdrClientLockClipboardData ClientLockClipboardData;
-		pcCliprdrServerLockClipboardData ServerLockClipboardData;
-		pcCliprdrClientUnlockClipboardData ClientUnlockClipboardData;
-		pcCliprdrServerUnlockClipboardData ServerUnlockClipboardData;
-		pcCliprdrClientFormatDataRequest ClientFormatDataRequest;
-		pcCliprdrServerFormatDataRequest ServerFormatDataRequest;
-		pcCliprdrClientFormatDataResponse ClientFormatDataResponse;
-		pcCliprdrServerFormatDataResponse ServerFormatDataResponse;
-		pcCliprdrClientFileContentsRequest ClientFileContentsRequest;
-		pcCliprdrServerFileContentsRequest ServerFileContentsRequest;
-		pcCliprdrClientFileContentsResponse ClientFileContentsResponse;
-		pcCliprdrServerFileContentsResponse ServerFileContentsResponse;
+		WINPR_ATTR_NODISCARD pcCliprdrServerCapabilities ServerCapabilities;
+		WINPR_ATTR_NODISCARD pcCliprdrClientCapabilities ClientCapabilities;
+		WINPR_ATTR_NODISCARD pcCliprdrMonitorReady MonitorReady;
+		WINPR_ATTR_NODISCARD pcCliprdrTempDirectory TempDirectory;
+		WINPR_ATTR_NODISCARD pcCliprdrClientFormatList ClientFormatList;
+		WINPR_ATTR_NODISCARD pcCliprdrServerFormatList ServerFormatList;
+		WINPR_ATTR_NODISCARD pcCliprdrClientFormatListResponse ClientFormatListResponse;
+		WINPR_ATTR_NODISCARD pcCliprdrServerFormatListResponse ServerFormatListResponse;
+		WINPR_ATTR_NODISCARD pcCliprdrClientLockClipboardData ClientLockClipboardData;
+		WINPR_ATTR_NODISCARD pcCliprdrServerLockClipboardData ServerLockClipboardData;
+		WINPR_ATTR_NODISCARD pcCliprdrClientUnlockClipboardData ClientUnlockClipboardData;
+		WINPR_ATTR_NODISCARD pcCliprdrServerUnlockClipboardData ServerUnlockClipboardData;
+		WINPR_ATTR_NODISCARD pcCliprdrClientFormatDataRequest ClientFormatDataRequest;
+		WINPR_ATTR_NODISCARD pcCliprdrServerFormatDataRequest ServerFormatDataRequest;
+		WINPR_ATTR_NODISCARD pcCliprdrClientFormatDataResponse ClientFormatDataResponse;
+		WINPR_ATTR_NODISCARD pcCliprdrServerFormatDataResponse ServerFormatDataResponse;
+		WINPR_ATTR_NODISCARD pcCliprdrClientFileContentsRequest ClientFileContentsRequest;
+		WINPR_ATTR_NODISCARD pcCliprdrServerFileContentsRequest ServerFileContentsRequest;
+		WINPR_ATTR_NODISCARD pcCliprdrClientFileContentsResponse ClientFileContentsResponse;
+		WINPR_ATTR_NODISCARD pcCliprdrServerFileContentsResponse ServerFileContentsResponse;

 		UINT32 lastRequestedFormatId;
 		rdpContext* rdpcontext;
--- a/include/freerdp/client/disp.h
+++ b/include/freerdp/client/disp.h
@@ -41,8 +41,8 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcDispCaps DisplayControlCaps;
-		pcDispSendMonitorLayout SendMonitorLayout;
+		WINPR_ATTR_NODISCARD pcDispCaps DisplayControlCaps;
+		WINPR_ATTR_NODISCARD pcDispSendMonitorLayout SendMonitorLayout;
 	};

 #ifdef __cplusplus
--- a/include/freerdp/client/drdynvc.h
+++ b/include/freerdp/client/drdynvc.h
@@ -22,6 +22,8 @@
 #ifndef FREERDP_CHANNEL_DRDYNVC_CLIENT_DRDYNVC_H
 #define FREERDP_CHANNEL_DRDYNVC_CLIENT_DRDYNVC_H

+#include <winpr/wtypes.h>
+
 #ifdef __cplusplus
 extern "C"
 {
@@ -48,11 +50,11 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcDrdynvcGetVersion GetVersion;
-		pcDrdynvcOnChannelConnected OnChannelConnected;
-		pcDrdynvcOnChannelDisconnected OnChannelDisconnected;
-		pcDrdynvcOnChannelAttached OnChannelAttached;
-		pcDrdynvcOnChannelDetached OnChannelDetached;
+		WINPR_ATTR_NODISCARD pcDrdynvcGetVersion GetVersion;
+		WINPR_ATTR_NODISCARD pcDrdynvcOnChannelConnected OnChannelConnected;
+		WINPR_ATTR_NODISCARD pcDrdynvcOnChannelDisconnected OnChannelDisconnected;
+		WINPR_ATTR_NODISCARD pcDrdynvcOnChannelAttached OnChannelAttached;
+		WINPR_ATTR_NODISCARD pcDrdynvcOnChannelDetached OnChannelDetached;
 	};

 #ifdef __cplusplus
--- a/include/freerdp/client/encomsp.h
+++ b/include/freerdp/client/encomsp.h
@@ -66,17 +66,17 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcEncomspFilterUpdated FilterUpdated;
-		pcEncomspApplicationCreated ApplicationCreated;
-		pcEncomspApplicationRemoved ApplicationRemoved;
-		pcEncomspWindowCreated WindowCreated;
-		pcEncomspWindowRemoved WindowRemoved;
-		pcEncomspShowWindow ShowWindow;
-		pcEncomspParticipantCreated ParticipantCreated;
-		pcEncomspParticipantRemoved ParticipantRemoved;
-		pcEncomspChangeParticipantControlLevel ChangeParticipantControlLevel;
-		pcEncomspGraphicsStreamPaused GraphicsStreamPaused;
-		pcEncomspGraphicsStreamResumed GraphicsStreamResumed;
+		WINPR_ATTR_NODISCARD pcEncomspFilterUpdated FilterUpdated;
+		WINPR_ATTR_NODISCARD pcEncomspApplicationCreated ApplicationCreated;
+		WINPR_ATTR_NODISCARD pcEncomspApplicationRemoved ApplicationRemoved;
+		WINPR_ATTR_NODISCARD pcEncomspWindowCreated WindowCreated;
+		WINPR_ATTR_NODISCARD pcEncomspWindowRemoved WindowRemoved;
+		WINPR_ATTR_NODISCARD pcEncomspShowWindow ShowWindow;
+		WINPR_ATTR_NODISCARD pcEncomspParticipantCreated ParticipantCreated;
+		WINPR_ATTR_NODISCARD pcEncomspParticipantRemoved ParticipantRemoved;
+		WINPR_ATTR_NODISCARD pcEncomspChangeParticipantControlLevel ChangeParticipantControlLevel;
+		WINPR_ATTR_NODISCARD pcEncomspGraphicsStreamPaused GraphicsStreamPaused;
+		WINPR_ATTR_NODISCARD pcEncomspGraphicsStreamResumed GraphicsStreamResumed;

 		UINT32 participantId;
 	};
--- a/include/freerdp/client/geometry.h
+++ b/include/freerdp/client/geometry.h
@@ -51,8 +51,8 @@ extern "C"
 		FREERDP_RGNDATA geometry;

 		void* custom;
-		pcMappedGeometryUpdate MappedGeometryUpdate;
-		pcMappedGeometryClear MappedGeometryClear;
+		WINPR_ATTR_NODISCARD pcMappedGeometryUpdate MappedGeometryUpdate;
+		WINPR_ATTR_NODISCARD pcMappedGeometryClear MappedGeometryClear;
 	};

 	/** @brief the geometry context for client channel */
@@ -62,7 +62,7 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcMappedGeometryAdded MappedGeometryAdded;
+		WINPR_ATTR_NODISCARD pcMappedGeometryAdded MappedGeometryAdded;
 		UINT32 remoteVersion;
 	};

--- a/include/freerdp/client/location.h
+++ b/include/freerdp/client/location.h
@@ -58,7 +58,7 @@ extern "C"
 		 *
 		 * \return \b CHANNEL_RC_OK for success, an appropriate error otherwise.
 		 */
-		pcLocationStart LocationStart;
+		WINPR_ATTR_NODISCARD pcLocationStart LocationStart;

 		/**! \brief stop location services on client
 		 *
@@ -66,7 +66,7 @@ extern "C"
 		 *
 		 * \return \b CHANNEL_RC_OK for success, an appropriate error otherwise.
 		 */
-		pcLocationStop LocationStop;
+		WINPR_ATTR_NODISCARD pcLocationStop LocationStop;

 		/**! \brief Send a location update.
 		 *
@@ -97,7 +97,7 @@ extern "C"
 		 *
 		 * return \b CHANNEL_RC_OK for success, an appropriate error otherwise.
 		 */
-		pcLocationSend LocationSend;
+		WINPR_ATTR_NODISCARD pcLocationSend LocationSend;
 	};

 #ifdef __cplusplus
--- a/include/freerdp/client/printer.h
+++ b/include/freerdp/client/printer.h
@@ -44,9 +44,9 @@ extern "C"

 	struct rdp_printer_driver
 	{
-		pcEnumPrinters EnumPrinters;
+		WINPR_ATTR_NODISCARD pcEnumPrinters EnumPrinters;
 		pcReleaseEnumPrinters ReleaseEnumPrinters;
-		pcGetPrinter GetPrinter;
+		WINPR_ATTR_NODISCARD pcGetPrinter GetPrinter;

 		pcReferencePrinterDriver AddRef;
 		pcReferencePrinterDriver ReleaseRef;
@@ -64,8 +64,8 @@ extern "C"

 		size_t references;
 		rdpPrinterDriver* backend;
-		pcCreatePrintJob CreatePrintJob;
-		pcFindPrintJob FindPrintJob;
+		WINPR_ATTR_NODISCARD pcCreatePrintJob CreatePrintJob;
+		WINPR_ATTR_NODISCARD pcFindPrintJob FindPrintJob;
 		pcReferencePrinter AddRef;
 		pcReferencePrinter ReleaseRef;
 	};
@@ -78,7 +78,7 @@ extern "C"
 		UINT32 id;
 		rdpPrinter* printer;

-		pcWritePrintJob Write;
+		WINPR_ATTR_NODISCARD pcWritePrintJob Write;
 		pcClosePrintJob Close;
 	};

--- a/include/freerdp/client/rail.h
+++ b/include/freerdp/client/rail.h
@@ -101,37 +101,37 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcRailClientExecute ClientExecute;
-		pcRailClientActivate ClientActivate;
-		pcRailClientSystemParam ClientSystemParam;
-		pcRailServerSystemParam ServerSystemParam;
-		pcRailClientSystemCommand ClientSystemCommand;
-		pcRailClientHandshake ClientHandshake;
-		pcRailServerHandshake ServerHandshake;
-		pcRailServerHandshakeEx ServerHandshakeEx;
-		pcRailClientNotifyEvent ClientNotifyEvent;
-		pcRailClientWindowMove ClientWindowMove;
-		pcRailServerLocalMoveSize ServerLocalMoveSize;
-		pcRailServerMinMaxInfo ServerMinMaxInfo;
-		pcRailClientInformation ClientInformation;
-		pcRailClientSystemMenu ClientSystemMenu;
-		pcRailServerTaskBarInfo ServerTaskBarInfo;
-		pcRailClientLanguageBarInfo ClientLanguageBarInfo;
-		pcRailServerLanguageBarInfo ServerLanguageBarInfo;
-		pcRailClientLanguageIMEInfo ClientLanguageIMEInfo;
-		pcRailServerExecuteResult ServerExecuteResult;
-		pcRailClientGetAppIdRequest ClientGetAppIdRequest;
-		pcRailServerGetAppIdResponse ServerGetAppIdResponse;
-		pcRailServerZOrderSync ServerZOrderSync;
-		pcRailClientCloak ClientCloak;
-		pcRailServerCloak ServerCloak;
-		pcRailServerPowerDisplayRequest ServerPowerDisplayRequest;
-		pcRailClientSnapArrange ClientSnapArrange;
-		pcRailServerGetAppidResponseExtended ServerGetAppidResponseExtended;
-		pcRailClientCompartmentInfo ClientCompartmentInfo;
-		pcRailOnOpen OnOpen;
-		pcRailClientTextScale ClientTextScale;
-		pcRailClientCaretBlinkRate ClientCaretBlinkRate;
+		WINPR_ATTR_NODISCARD pcRailClientExecute ClientExecute;
+		WINPR_ATTR_NODISCARD pcRailClientActivate ClientActivate;
+		WINPR_ATTR_NODISCARD pcRailClientSystemParam ClientSystemParam;
+		WINPR_ATTR_NODISCARD pcRailServerSystemParam ServerSystemParam;
+		WINPR_ATTR_NODISCARD pcRailClientSystemCommand ClientSystemCommand;
+		WINPR_ATTR_NODISCARD pcRailClientHandshake ClientHandshake;
+		WINPR_ATTR_NODISCARD pcRailServerHandshake ServerHandshake;
+		WINPR_ATTR_NODISCARD pcRailServerHandshakeEx ServerHandshakeEx;
+		WINPR_ATTR_NODISCARD pcRailClientNotifyEvent ClientNotifyEvent;
+		WINPR_ATTR_NODISCARD pcRailClientWindowMove ClientWindowMove;
+		WINPR_ATTR_NODISCARD pcRailServerLocalMoveSize ServerLocalMoveSize;
+		WINPR_ATTR_NODISCARD pcRailServerMinMaxInfo ServerMinMaxInfo;
+		WINPR_ATTR_NODISCARD pcRailClientInformation ClientInformation;
+		WINPR_ATTR_NODISCARD pcRailClientSystemMenu ClientSystemMenu;
+		WINPR_ATTR_NODISCARD pcRailServerTaskBarInfo ServerTaskBarInfo;
+		WINPR_ATTR_NODISCARD pcRailClientLanguageBarInfo ClientLanguageBarInfo;
+		WINPR_ATTR_NODISCARD pcRailServerLanguageBarInfo ServerLanguageBarInfo;
+		WINPR_ATTR_NODISCARD pcRailClientLanguageIMEInfo ClientLanguageIMEInfo;
+		WINPR_ATTR_NODISCARD pcRailServerExecuteResult ServerExecuteResult;
+		WINPR_ATTR_NODISCARD pcRailClientGetAppIdRequest ClientGetAppIdRequest;
+		WINPR_ATTR_NODISCARD pcRailServerGetAppIdResponse ServerGetAppIdResponse;
+		WINPR_ATTR_NODISCARD pcRailServerZOrderSync ServerZOrderSync;
+		WINPR_ATTR_NODISCARD pcRailClientCloak ClientCloak;
+		WINPR_ATTR_NODISCARD pcRailServerCloak ServerCloak;
+		WINPR_ATTR_NODISCARD pcRailServerPowerDisplayRequest ServerPowerDisplayRequest;
+		WINPR_ATTR_NODISCARD pcRailClientSnapArrange ClientSnapArrange;
+		WINPR_ATTR_NODISCARD pcRailServerGetAppidResponseExtended ServerGetAppidResponseExtended;
+		WINPR_ATTR_NODISCARD pcRailClientCompartmentInfo ClientCompartmentInfo;
+		WINPR_ATTR_NODISCARD pcRailOnOpen OnOpen;
+		WINPR_ATTR_NODISCARD pcRailClientTextScale ClientTextScale;
+		WINPR_ATTR_NODISCARD pcRailClientCaretBlinkRate ClientCaretBlinkRate;
 	};

 	FREERDP_API UINT client_rail_server_start_cmd(RailClientContext* context);
--- a/include/freerdp/client/rdpdr.h
+++ b/include/freerdp/client/rdpdr.h
@@ -86,9 +86,9 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcRdpdrRegisterDevice RdpdrRegisterDevice;
-		pcRdpdrUnregisterDevice RdpdrUnregisterDevice;
-		pcRdpdrHotplugDevice RdpdrHotplugDevice;
+		WINPR_ATTR_NODISCARD pcRdpdrRegisterDevice RdpdrRegisterDevice;
+		WINPR_ATTR_NODISCARD pcRdpdrUnregisterDevice RdpdrUnregisterDevice;
+		WINPR_ATTR_NODISCARD pcRdpdrHotplugDevice RdpdrHotplugDevice;
 	};

 #ifdef __cplusplus
--- a/include/freerdp/client/rdpei.h
+++ b/include/freerdp/client/rdpei.h
@@ -71,34 +71,34 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcRdpeiGetVersion GetVersion;
-		pcRdpeiGetFeatures GetFeatures;
+		WINPR_ATTR_NODISCARD pcRdpeiGetVersion GetVersion;
+		WINPR_ATTR_NODISCARD pcRdpeiGetFeatures GetFeatures;

-		pcRdpeiAddContact AddContact;
+		WINPR_ATTR_NODISCARD pcRdpeiAddContact AddContact;

-		pcRdpeiTouchEvent TouchBegin;
-		pcRdpeiTouchEvent TouchUpdate;
-		pcRdpeiTouchEvent TouchEnd;
+		WINPR_ATTR_NODISCARD pcRdpeiTouchEvent TouchBegin;
+		WINPR_ATTR_NODISCARD pcRdpeiTouchEvent TouchUpdate;
+		WINPR_ATTR_NODISCARD pcRdpeiTouchEvent TouchEnd;

-		pcRdpeiAddPen AddPen;
+		WINPR_ATTR_NODISCARD pcRdpeiAddPen AddPen;

-		pcRdpeiPen PenBegin;
-		pcRdpeiPen PenUpdate;
-		pcRdpeiPen PenEnd;
-		pcRdpeiPen PenHoverBegin;
-		pcRdpeiPen PenHoverUpdate;
-		pcRdpeiPen PenHoverCancel;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenBegin;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenUpdate;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenEnd;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenHoverBegin;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenHoverUpdate;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenHoverCancel;

-		pcRdpeiSuspendTouch SuspendTouch;
-		pcRdpeiResumeTouch ResumeTouch;
+		WINPR_ATTR_NODISCARD pcRdpeiSuspendTouch SuspendTouch;
+		WINPR_ATTR_NODISCARD pcRdpeiResumeTouch ResumeTouch;

-		pcRdpeiTouchEvent TouchCancel;
-		pcRdpeiTouchRawEvent TouchRawEvent;
-		pcRdpeiTouchRawEventVA TouchRawEventVA;
+		WINPR_ATTR_NODISCARD pcRdpeiTouchEvent TouchCancel;
+		WINPR_ATTR_NODISCARD pcRdpeiTouchRawEvent TouchRawEvent;
+		WINPR_ATTR_NODISCARD pcRdpeiTouchRawEventVA TouchRawEventVA;

-		pcRdpeiPen PenCancel;
-		pcRdpeiPenRawEvent PenRawEvent;
-		pcRdpeiPenRawEventVA PenRawEventVA;
+		WINPR_ATTR_NODISCARD pcRdpeiPen PenCancel;
+		WINPR_ATTR_NODISCARD pcRdpeiPenRawEvent PenRawEvent;
+		WINPR_ATTR_NODISCARD pcRdpeiPenRawEventVA PenRawEventVA;

 		UINT32 clientFeaturesMask;
 	};
--- a/include/freerdp/client/rdpgfx.h
+++ b/include/freerdp/client/rdpgfx.h
@@ -125,52 +125,52 @@ extern "C"
 		void* custom;

 		/* Implementations require locking */
-		pcRdpgfxResetGraphics ResetGraphics;
-		pcRdpgfxStartFrame StartFrame;
-		pcRdpgfxEndFrame EndFrame;
-		pcRdpgfxSurfaceCommand SurfaceCommand;
-		pcRdpgfxDeleteEncodingContext DeleteEncodingContext;
-		pcRdpgfxCreateSurface CreateSurface;
-		pcRdpgfxDeleteSurface DeleteSurface;
-		pcRdpgfxSolidFill SolidFill;
-		pcRdpgfxSurfaceToSurface SurfaceToSurface;
-		pcRdpgfxSurfaceToCache SurfaceToCache;
-		pcRdpgfxCacheToSurface CacheToSurface;
-		pcRdpgfxCacheImportOffer CacheImportOffer;
-		pcRdpgfxCacheImportReply CacheImportReply;
-		pcRdpgfxImportCacheEntry ImportCacheEntry;
-		pcRdpgfxExportCacheEntry ExportCacheEntry;
-		pcRdpgfxEvictCacheEntry EvictCacheEntry;
-		pcRdpgfxMapSurfaceToOutput MapSurfaceToOutput;
-		pcRdpgfxMapSurfaceToScaledOutput MapSurfaceToScaledOutput;
-		pcRdpgfxMapSurfaceToWindow MapSurfaceToWindow;
-		pcRdpgfxMapSurfaceToScaledWindow MapSurfaceToScaledWindow;
+		WINPR_ATTR_NODISCARD pcRdpgfxResetGraphics ResetGraphics;
+		WINPR_ATTR_NODISCARD pcRdpgfxStartFrame StartFrame;
+		WINPR_ATTR_NODISCARD pcRdpgfxEndFrame EndFrame;
+		WINPR_ATTR_NODISCARD pcRdpgfxSurfaceCommand SurfaceCommand;
+		WINPR_ATTR_NODISCARD pcRdpgfxDeleteEncodingContext DeleteEncodingContext;
+		WINPR_ATTR_NODISCARD pcRdpgfxCreateSurface CreateSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxDeleteSurface DeleteSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxSolidFill SolidFill;
+		WINPR_ATTR_NODISCARD pcRdpgfxSurfaceToSurface SurfaceToSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxSurfaceToCache SurfaceToCache;
+		WINPR_ATTR_NODISCARD pcRdpgfxCacheToSurface CacheToSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxCacheImportOffer CacheImportOffer;
+		WINPR_ATTR_NODISCARD pcRdpgfxCacheImportReply CacheImportReply;
+		WINPR_ATTR_NODISCARD pcRdpgfxImportCacheEntry ImportCacheEntry;
+		WINPR_ATTR_NODISCARD pcRdpgfxExportCacheEntry ExportCacheEntry;
+		WINPR_ATTR_NODISCARD pcRdpgfxEvictCacheEntry EvictCacheEntry;
+		WINPR_ATTR_NODISCARD pcRdpgfxMapSurfaceToOutput MapSurfaceToOutput;
+		WINPR_ATTR_NODISCARD pcRdpgfxMapSurfaceToScaledOutput MapSurfaceToScaledOutput;
+		WINPR_ATTR_NODISCARD pcRdpgfxMapSurfaceToWindow MapSurfaceToWindow;
+		WINPR_ATTR_NODISCARD pcRdpgfxMapSurfaceToScaledWindow MapSurfaceToScaledWindow;

-		pcRdpgfxGetSurfaceIds GetSurfaceIds;
-		pcRdpgfxSetSurfaceData SetSurfaceData;
-		pcRdpgfxGetSurfaceData GetSurfaceData;
-		pcRdpgfxSetCacheSlotData SetCacheSlotData;
-		pcRdpgfxGetCacheSlotData GetCacheSlotData;
+		WINPR_ATTR_NODISCARD pcRdpgfxGetSurfaceIds GetSurfaceIds;
+		WINPR_ATTR_NODISCARD pcRdpgfxSetSurfaceData SetSurfaceData;
+		WINPR_ATTR_NODISCARD pcRdpgfxGetSurfaceData GetSurfaceData;
+		WINPR_ATTR_NODISCARD pcRdpgfxSetCacheSlotData SetCacheSlotData;
+		WINPR_ATTR_NODISCARD pcRdpgfxGetCacheSlotData GetCacheSlotData;

 		/* Proxy callbacks */
-		pcRdpgfxOnOpen OnOpen;
-		pcRdpgfxOnClose OnClose;
-		pcRdpgfxCapsAdvertise CapsAdvertise;
-		pcRdpgfxCapsConfirm CapsConfirm;
-		pcRdpgfxFrameAcknowledge FrameAcknowledge;
-		pcRdpgfxQoeFrameAcknowledge QoeFrameAcknowledge;
+		WINPR_ATTR_NODISCARD pcRdpgfxOnOpen OnOpen;
+		WINPR_ATTR_NODISCARD pcRdpgfxOnClose OnClose;
+		WINPR_ATTR_NODISCARD pcRdpgfxCapsAdvertise CapsAdvertise;
+		WINPR_ATTR_NODISCARD pcRdpgfxCapsConfirm CapsConfirm;
+		WINPR_ATTR_NODISCARD pcRdpgfxFrameAcknowledge FrameAcknowledge;
+		WINPR_ATTR_NODISCARD pcRdpgfxQoeFrameAcknowledge QoeFrameAcknowledge;

 		/* No locking required */
-		pcRdpgfxUpdateSurfaces UpdateSurfaces;
-		pcRdpgfxUpdateSurfaceArea UpdateSurfaceArea;
-		pcRdpgfxUpdateWindowFromSurface UpdateWindowFromSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxUpdateSurfaces UpdateSurfaces;
+		WINPR_ATTR_NODISCARD pcRdpgfxUpdateSurfaceArea UpdateSurfaceArea;
+		WINPR_ATTR_NODISCARD pcRdpgfxUpdateWindowFromSurface UpdateWindowFromSurface;

 		/* These callbacks allow creating/destroying a window directly
 		 * mapped to a surface.
 		 * NOTE: The surface is already locked.
 		 */
-		pcRdpgfxMapWindowForSurface MapWindowForSurface;
-		pcRdpgfxUnmapWindowForSurface UnmapWindowForSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxMapWindowForSurface MapWindowForSurface;
+		WINPR_ATTR_NODISCARD pcRdpgfxUnmapWindowForSurface UnmapWindowForSurface;

 		CRITICAL_SECTION mux;
 		rdpCodecs* codecs;
--- a/include/freerdp/client/rdpsnd.h
+++ b/include/freerdp/client/rdpsnd.h
@@ -55,17 +55,17 @@ extern "C"
 	{
 		rdpsndPlugin* rdpsnd;

-		pcFormatSupported FormatSupported;
-		pcOpen Open;
-		pcGetVolume GetVolume;
-		pcSetVolume SetVolume;
-		pcPlay Play;
+		WINPR_ATTR_NODISCARD pcFormatSupported FormatSupported;
+		WINPR_ATTR_NODISCARD pcOpen Open;
+		WINPR_ATTR_NODISCARD pcGetVolume GetVolume;
+		WINPR_ATTR_NODISCARD pcSetVolume SetVolume;
+		WINPR_ATTR_NODISCARD pcPlay Play;
 		pcStart Start; /* Deprecated, unused. */
 		pcClose Close;
 		pcFree Free;
-		pcDefaultFormat DefaultFormat;
-		pcServerFormatAnnounce ServerFormatAnnounce;
-		pcPlayEx PlayEx;
+		WINPR_ATTR_NODISCARD pcDefaultFormat DefaultFormat;
+		WINPR_ATTR_NODISCARD pcServerFormatAnnounce ServerFormatAnnounce;
+		WINPR_ATTR_NODISCARD pcPlayEx PlayEx;
 	};

 #define RDPSND_DEVICE_EXPORT_FUNC_NAME "freerdp_rdpsnd_client_subsystem_entry"
--- a/include/freerdp/client/tsmf.h
+++ b/include/freerdp/client/tsmf.h
@@ -69,7 +69,7 @@ extern "C"
 		void* handle;
 		void* custom;

-		pcTsmfFrameEvent FrameEvent;
+		WINPR_ATTR_NODISCARD pcTsmfFrameEvent FrameEvent;
 	};

 #ifdef __cplusplus
--- a/include/freerdp/client/video.h
+++ b/include/freerdp/client/video.h
@@ -58,8 +58,8 @@ extern "C"

 		pcVideoSetGeometry setGeometry;
 		pcVideoTimer timer;
-		pcVideoCreateSurface createSurface;
-		pcVideoShowSurface showSurface;
+		WINPR_ATTR_NODISCARD pcVideoCreateSurface createSurface;
+		WINPR_ATTR_NODISCARD pcVideoShowSurface showSurface;
 		pcVideoDeleteSurface deleteSurface;
 	};

--- a/include/freerdp/dvc.h
+++ b/include/freerdp/dvc.h
@@ -73,7 +73,8 @@ extern "C"
 	struct s_IWTSListener
 	{
 		/* Retrieves the listener-specific configuration. */
-		UINT (*GetConfiguration)(IWTSListener* pListener, void** ppPropertyBag);
+		WINPR_ATTR_NODISCARD UINT (*GetConfiguration)(IWTSListener* pListener,
+		                                              void** ppPropertyBag);

 		void* pInterface;
 	};
@@ -81,45 +82,47 @@ extern "C"
 	struct s_IWTSVirtualChannel
 	{
 		/* Starts a write request on the channel. */
-		UINT(*Write)
-		(IWTSVirtualChannel* pChannel, ULONG cbSize, const BYTE* pBuffer, void* pReserved);
+		WINPR_ATTR_NODISCARD UINT (*Write)(IWTSVirtualChannel* pChannel, ULONG cbSize,
+		                                   const BYTE* pBuffer, void* pReserved);
 		/* Closes the channel. */
-		UINT (*Close)(IWTSVirtualChannel* pChannel);
+		WINPR_ATTR_NODISCARD UINT (*Close)(IWTSVirtualChannel* pChannel);
 	};

 	struct s_IWTSVirtualChannelManager
 	{
 		/* Returns an instance of a listener object that listens on a specific
 		   endpoint, or creates a static channel. */
-		UINT(*CreateListener)
-		(IWTSVirtualChannelManager* pChannelMgr, const char* pszChannelName, ULONG ulFlags,
-		 IWTSListenerCallback* pListenerCallback, IWTSListener** ppListener);
+		WINPR_ATTR_NODISCARD UINT (*CreateListener)(IWTSVirtualChannelManager* pChannelMgr,
+		                                            const char* pszChannelName, ULONG ulFlags,
+		                                            IWTSListenerCallback* pListenerCallback,
+		                                            IWTSListener** ppListener);
 		/* Find the channel or ID to send data to a specific endpoint. */
-		UINT32 (*GetChannelId)(IWTSVirtualChannel* channel);
-		IWTSVirtualChannel* (*FindChannelById)(IWTSVirtualChannelManager* pChannelMgr,
-		                                       UINT32 ChannelId);
-		const char* (*GetChannelName)(IWTSVirtualChannel* channel);
+		WINPR_ATTR_NODISCARD UINT32 (*GetChannelId)(IWTSVirtualChannel* channel);
+		WINPR_ATTR_NODISCARD IWTSVirtualChannel* (*FindChannelById)(
+		    IWTSVirtualChannelManager* pChannelMgr, UINT32 ChannelId);
+		WINPR_ATTR_NODISCARD const char* (*GetChannelName)(IWTSVirtualChannel* channel);
 		UINT (*DestroyListener)(IWTSVirtualChannelManager* pChannelMgr, IWTSListener* ppListener);
 	};

 	struct s_IWTSPlugin
 	{
 		/* Used for the first call that is made from the client to the plug-in. */
-		UINT (*Initialize)(IWTSPlugin* pPlugin, IWTSVirtualChannelManager* pChannelMgr);
+		WINPR_ATTR_NODISCARD UINT (*Initialize)(IWTSPlugin* pPlugin,
+		                                        IWTSVirtualChannelManager* pChannelMgr);
 		/* Notifies the plug-in that the Remote Desktop Connection (RDC) client
 		   has successfully connected to the Remote Desktop Session Host (RD
 		   Session Host) server. */
-		UINT (*Connected)(IWTSPlugin* pPlugin);
+		WINPR_ATTR_NODISCARD UINT (*Connected)(IWTSPlugin* pPlugin);
 		/* Notifies the plug-in that the Remote Desktop Connection (RDC) client
 		   has disconnected from the RD Session Host server. */
-		UINT (*Disconnected)(IWTSPlugin* pPlugin, DWORD dwDisconnectCode);
+		WINPR_ATTR_NODISCARD UINT (*Disconnected)(IWTSPlugin* pPlugin, DWORD dwDisconnectCode);
 		/* Notifies the plug-in that the Remote Desktop Connection (RDC) client
 		   has terminated. */
-		UINT (*Terminated)(IWTSPlugin* pPlugin);
+		WINPR_ATTR_NODISCARD UINT (*Terminated)(IWTSPlugin* pPlugin);

-		UINT (*Attached)(IWTSPlugin* pPlugin);
+		WINPR_ATTR_NODISCARD UINT (*Attached)(IWTSPlugin* pPlugin);

-		UINT (*Detached)(IWTSPlugin* pPlugin);
+		WINPR_ATTR_NODISCARD UINT (*Detached)(IWTSPlugin* pPlugin);

 		/* Extended */

@@ -130,24 +133,25 @@ extern "C"
 	{
 		/* Accepts or denies a connection request for an incoming connection to
 		   the associated listener. */
-		UINT(*OnNewChannelConnection)
-		(IWTSListenerCallback* pListenerCallback, IWTSVirtualChannel* pChannel, BYTE* Data,
-		 BOOL* pbAccept, IWTSVirtualChannelCallback** ppCallback);
+		WINPR_ATTR_NODISCARD
+		UINT (*OnNewChannelConnection)(IWTSListenerCallback* pListenerCallback,
+		                               IWTSVirtualChannel* pChannel, BYTE* Data, BOOL* pbAccept,
+		                               IWTSVirtualChannelCallback** ppCallback);

 		void* pInterface;
 	};

 	struct s_IWTSVirtualChannelCallback
 	{
-		UINT(*OnDataReceived)
-		(IWTSVirtualChannelCallback* pChannelCallback,
-		 wStream* data); /**< Notifies the user about data that is being received. */
-		UINT(*OnOpen)
-		(IWTSVirtualChannelCallback*
-		     pChannelCallback); /**< Notifies the user that the channel has been opened. */
-		UINT(*OnClose)
-		(IWTSVirtualChannelCallback*
-		     pChannelCallback); /**< Notifies the user that the channel has been closed. */
+		WINPR_ATTR_NODISCARD UINT (*OnDataReceived)(
+		    IWTSVirtualChannelCallback* pChannelCallback,
+		    wStream* data); /**< Notifies the user about data that is being received. */
+		WINPR_ATTR_NODISCARD UINT (*OnOpen)(
+		    IWTSVirtualChannelCallback*
+		        pChannelCallback); /**< Notifies the user that the channel has been opened. */
+		WINPR_ATTR_NODISCARD UINT (*OnClose)(
+		    IWTSVirtualChannelCallback*
+		        pChannelCallback); /**< Notifies the user that the channel has been closed. */

 		void* pInterface;
 	};
@@ -159,15 +163,15 @@ extern "C"
 	typedef struct S_IDRDYNVC_ENTRY_POINTS IDRDYNVC_ENTRY_POINTS;
 	struct S_IDRDYNVC_ENTRY_POINTS
 	{
-		UINT(*RegisterPlugin)
-		(IDRDYNVC_ENTRY_POINTS* pEntryPoints, const char* name, IWTSPlugin* pPlugin);
+		WINPR_ATTR_NODISCARD UINT (*RegisterPlugin)(IDRDYNVC_ENTRY_POINTS* pEntryPoints,
+		                                            const char* name, IWTSPlugin* pPlugin);
 		IWTSPlugin* (*GetPlugin)(IDRDYNVC_ENTRY_POINTS* pEntryPoints, const char* name);
 		const ADDIN_ARGV* (*GetPluginData)(IDRDYNVC_ENTRY_POINTS* pEntryPoints);
-		rdpSettings* (*GetRdpSettings)(IDRDYNVC_ENTRY_POINTS* pEntryPoints);
-		rdpContext* (*GetRdpContext)(IDRDYNVC_ENTRY_POINTS* pEntryPoints);
+		WINPR_ATTR_NODISCARD rdpSettings* (*GetRdpSettings)(IDRDYNVC_ENTRY_POINTS* pEntryPoints);
+		WINPR_ATTR_NODISCARD rdpContext* (*GetRdpContext)(IDRDYNVC_ENTRY_POINTS* pEntryPoints);
 	};

-	typedef UINT(VCAPITYPE* PDVC_PLUGIN_ENTRY)(IDRDYNVC_ENTRY_POINTS*);
+	typedef WINPR_ATTR_NODISCARD UINT(VCAPITYPE* PDVC_PLUGIN_ENTRY)(IDRDYNVC_ENTRY_POINTS*);

 	void* get_callback_by_name(const char* name, void** context);
 	void add_callback_by_name(const char* name, void* fkt, void* context);
--- a/include/freerdp/extension.h
+++ b/include/freerdp/extension.h
@@ -35,29 +35,32 @@ extern "C"
 	struct rdp_ext_plugin
 	{
 		void* ext;
-		int (*init)(rdpExtPlugin* plugin, freerdp* instance);
-		int (*uninit)(rdpExtPlugin* plugin, freerdp* instance);
+		WINPR_ATTR_NODISCARD int (*init)(rdpExtPlugin* plugin, freerdp* instance);
+		WINPR_ATTR_NODISCARD int (*uninit)(rdpExtPlugin* plugin, freerdp* instance);
 	};

-	typedef UINT32(FREERDP_CC* PFREERDP_EXTENSION_HOOK)(rdpExtPlugin* plugin, freerdp* instance);
+	typedef WINPR_ATTR_NODISCARD UINT32(FREERDP_CC* PFREERDP_EXTENSION_HOOK)(rdpExtPlugin* plugin,
+	                                                                         freerdp* instance);

-	typedef UINT32(FREERDP_CC* PREGISTEREXTENSION)(rdpExtPlugin* plugin);
-	typedef UINT32(FREERDP_CC* PREGISTERPRECONNECTHOOK)(rdpExtPlugin* plugin,
-	                                                    PFREERDP_EXTENSION_HOOK hook);
-	typedef UINT32(FREERDP_CC* PREGISTERPOSTCONNECTHOOK)(rdpExtPlugin* plugin,
-	                                                     PFREERDP_EXTENSION_HOOK hook);
+	typedef WINPR_ATTR_NODISCARD UINT32(FREERDP_CC* PREGISTEREXTENSION)(rdpExtPlugin* plugin);
+	typedef WINPR_ATTR_NODISCARD
+	UINT32(FREERDP_CC* PREGISTERPRECONNECTHOOK)(rdpExtPlugin* plugin, PFREERDP_EXTENSION_HOOK hook);
+	typedef WINPR_ATTR_NODISCARD
+	UINT32(FREERDP_CC* PREGISTERPOSTCONNECTHOOK)(rdpExtPlugin* plugin,
+	                                             PFREERDP_EXTENSION_HOOK hook);

 	typedef struct
 	{
 		void* ext; /* Reference to internal instance */
-		PREGISTEREXTENSION pRegisterExtension;
-		PREGISTERPRECONNECTHOOK pRegisterPreConnectHook;
-		PREGISTERPOSTCONNECTHOOK pRegisterPostConnectHook;
+		WINPR_ATTR_NODISCARD PREGISTEREXTENSION pRegisterExtension;
+		WINPR_ATTR_NODISCARD PREGISTERPRECONNECTHOOK pRegisterPreConnectHook;
+		WINPR_ATTR_NODISCARD PREGISTERPOSTCONNECTHOOK pRegisterPostConnectHook;
 		void* data;
 	} FREERDP_EXTENSION_ENTRY_POINTS;
 	typedef FREERDP_EXTENSION_ENTRY_POINTS* PFREERDP_EXTENSION_ENTRY_POINTS;

-	typedef int(FREERDP_CC* PFREERDP_EXTENSION_ENTRY)(PFREERDP_EXTENSION_ENTRY_POINTS pEntryPoints);
+	typedef WINPR_ATTR_NODISCARD int(FREERDP_CC* PFREERDP_EXTENSION_ENTRY)(
+	    PFREERDP_EXTENSION_ENTRY_POINTS pEntryPoints);

 #ifdef __cplusplus
 }
--- a/include/freerdp/freerdp.h
+++ b/include/freerdp/freerdp.h
@@ -477,7 +477,7 @@ owned by rdpRdp */
 		             additional information after that.
 		          */

-		ALIGN64 pContextNew
+		ALIGN64 WINPR_ATTR_NODISCARD pContextNew
 		    ContextNew; /**< (offset 33)
 		             Callback for context allocation
 		             Can be set before calling freerdp_context_new() to have it executed after
@@ -492,36 +492,37 @@ owned by rdpRdp */

 		ALIGN64 UINT ConnectionCallbackState; /* 47 */

-		ALIGN64 pConnectCallback
+		ALIGN64 WINPR_ATTR_NODISCARD pConnectCallback
 		    PreConnect; /**< (offset 48)
 		             Callback for pre-connect operations.
 		             Can be set before calling freerdp_connect() to have it executed before the
 		             actual connection happens. Must be set to NULL if not needed. */

-		ALIGN64 pConnectCallback
+		ALIGN64 WINPR_ATTR_NODISCARD pConnectCallback
 		    PostConnect; /**< (offset 49)
 		              Callback for post-connect operations.
 		              Can be set before calling freerdp_connect() to have it executed after the
 		              actual connection has succeeded. Must be set to NULL if not needed. */

-		ALIGN64 pAuthenticate Authenticate; /**< (offset 50)
+		ALIGN64 WINPR_ATTR_NODISCARD pAuthenticate Authenticate; /**< (offset 50)
 		                                 Callback for authentication.
 		                                 It is used to get the username/password when it was not
 		                                 provided at connection time. */
 #if defined(WITH_FREERDP_DEPRECATED)
 		WINPR_DEPRECATED_VAR("Use VerifyCertificateEx or VerifyX509Certificate  instead",
-		                     ALIGN64 pVerifyCertificate VerifyCertificate;) /**< (offset 51) */
+		                     ALIGN64 WINPR_ATTR_NODISCARD pVerifyCertificate
+		                         VerifyCertificate;) /**< (offset 51) */
 		WINPR_DEPRECATED_VAR("Use VerifyChangedCertificateEx or VerifyX509Certificate  instead",
-		                     ALIGN64 pVerifyChangedCertificate
+		                     ALIGN64 WINPR_ATTR_NODISCARD pVerifyChangedCertificate
 		                         VerifyChangedCertificate;) /**< (offset 52) */
 #else
 	ALIGN64 UINT64 reserved[2];
 #endif
-		ALIGN64 pVerifyX509Certificate
+		ALIGN64 WINPR_ATTR_NODISCARD pVerifyX509Certificate
 		    VerifyX509Certificate; /**< (offset 53)  Callback for X509 certificate verification
 		                              (PEM format) */

-		ALIGN64 pLogonErrorInfo
+		ALIGN64 WINPR_ATTR_NODISCARD pLogonErrorInfo
 		    LogonErrorInfo; /**< (offset 54)  Callback for logon error info, important for logon
 		                       system messages with RemoteApp */

@@ -534,22 +535,22 @@ owned by rdpRdp */
 		                       channels.
 */

-		ALIGN64 pAuthenticate GatewayAuthenticate; /**< (offset 56)
+		ALIGN64 WINPR_ATTR_NODISCARD pAuthenticate GatewayAuthenticate; /**< (offset 56)
 		                                 Callback for gateway authentication.
 		                                 It is used to get the username/password when it was not
 		                                 provided at connection time. */

-		ALIGN64 pPresentGatewayMessage PresentGatewayMessage; /**< (offset 57)
+		ALIGN64 WINPR_ATTR_NODISCARD pPresentGatewayMessage PresentGatewayMessage; /**< (offset 57)
 		                                  Callback for gateway consent messages.
 		                                  It is used to present consent messages to the user. */

-		ALIGN64 pConnectCallback Redirect; /**< (offset 58)
+		ALIGN64 WINPR_ATTR_NODISCARD pConnectCallback Redirect; /**< (offset 58)
 		                                               Callback for redirect operations.
 		                                               Can be set after
 		             rdp_client_disconnect_and_clear and applying redirection settings but before
 		             rdp_client_connect() to have it executed after the actual connection has
 		             succeeded. Must be set to NULL if not needed. */
-		ALIGN64 pConnectCallback
+		ALIGN64 WINPR_ATTR_NODISCARD pConnectCallback
 		    LoadChannels; /**< (offset 59)
 		                   * callback for loading channel configuration. Might be called multiple
 		                   * times when redirection occurs. */
@@ -563,46 +564,47 @@ owned by rdpRdp */
 		                           */
 		UINT64 paddingD[64 - 61]; /* 61 */

-		ALIGN64 pSendChannelData
+		ALIGN64 WINPR_ATTR_NODISCARD pSendChannelData
 		    SendChannelData; /* (offset 64)
 		                Callback for sending data to a channel.
 		                By default, it is set by freerdp_new() to freerdp_send_channel_data(), which
 		                eventually calls freerdp_channel_send() */
-		ALIGN64 pReceiveChannelData
+		ALIGN64 WINPR_ATTR_NODISCARD pReceiveChannelData
 		    ReceiveChannelData; /* (offset 65)
 		                   Callback for receiving data from a channel.
 		                   This is called by freerdp_channel_process() (if not NULL).
 		                   Clients will typically use a function that calls freerdp_channels_data()
 		                   to perform the needed tasks. */

-		ALIGN64 pVerifyCertificateEx
+		ALIGN64 WINPR_ATTR_NODISCARD pVerifyCertificateEx
 		    VerifyCertificateEx; /**< (offset 66)
 		                  Callback for certificate validation.
 		                  Used to verify that an unknown certificate is trusted. */
-		ALIGN64 pVerifyChangedCertificateEx
+		ALIGN64 WINPR_ATTR_NODISCARD pVerifyChangedCertificateEx
 		    VerifyChangedCertificateEx; /**< (offset 67)
 		                         Callback for changed certificate validation.
 		                         Used when a certificate differs from stored fingerprint. */
-		ALIGN64 pSendChannelPacket
-		    SendChannelPacket;                  /* (offset 68)
-		                                         * Callback for sending RAW data to a channel. In contrast to
-		                                         * SendChannelData data fragmentation    is up to the user and this
-		                                         * function sends data as is with the provided flags.
-		                                         */
-		ALIGN64 pAuthenticateEx AuthenticateEx; /**< (offset 69)
+		ALIGN64 WINPR_ATTR_NODISCARD pSendChannelPacket
+		    SendChannelPacket;                                       /* (offset 68)
+		                                                              * Callback for sending RAW data to a channel. In contrast to
+		                                                              * SendChannelData data fragmentation    is up to the user and this
+		                                                              * function sends data as is with the provided flags.
+		                                                              */
+		ALIGN64 WINPR_ATTR_NODISCARD pAuthenticateEx AuthenticateEx; /**< (offset 69)
 		                                 Callback for authentication.
 		                                 It is used to get the username/password. The reason
 		                                 argument tells why it was called.  */
-		ALIGN64 pChooseSmartcard
-		    ChooseSmartcard;                    /* (offset 70)
-		                                      Callback for choosing a smartcard for logon.
-		                                      Used when multiple smartcards are available. Returns an index into a list
-		                                      of SmartcardCertInfo pointers	*/
-		ALIGN64 pGetAccessToken GetAccessToken; /* (offset 71)
+		ALIGN64 WINPR_ATTR_NODISCARD pChooseSmartcard
+		    ChooseSmartcard;                                         /* (offset 70)
+		                                                           Callback for choosing a smartcard for logon.
+		                                                           Used when multiple smartcards are available. Returns an index into a list
+		                                                           of SmartcardCertInfo pointers	*/
+		ALIGN64 WINPR_ATTR_NODISCARD pGetAccessToken GetAccessToken; /* (offset 71)
 		                                            Callback for obtaining an access token
 		                                            for \b AccessTokenType authentication */
-		ALIGN64 pRetryDialog RetryDialog; /* (offset 72) Callback for displaying a dialog in case of
-		                                     something needs a retry */
+		ALIGN64 WINPR_ATTR_NODISCARD pRetryDialog
+		    RetryDialog;                  /* (offset 72) Callback for displaying a dialog in case of
+		                something needs a retry */
 		UINT64 paddingE[80 - 73];         /* 73 */
 	};

--- a/include/freerdp/graphics.h
+++ b/include/freerdp/graphics.h
@@ -47,11 +47,11 @@ extern "C"
 	struct rdp_bitmap
 	{
 		size_t size;                   /* 0 */
-		pBitmap_New New;               /* 1 */
-		pBitmap_Free Free;             /* 2 */
-		pBitmap_Paint Paint;           /* 3 */
-		pBitmap_Decompress Decompress; /* 4 */
-		pBitmap_SetSurface SetSurface; /* 5 */
+		WINPR_ATTR_NODISCARD pBitmap_New New;               /* 1 */
+		pBitmap_Free Free;                                  /* 2 */
+		WINPR_ATTR_NODISCARD pBitmap_Paint Paint;           /* 3 */
+		WINPR_ATTR_NODISCARD pBitmap_Decompress Decompress; /* 4 */
+		WINPR_ATTR_NODISCARD pBitmap_SetSurface SetSurface; /* 5 */
 		UINT32 paddingA[16 - 6];       /* 6 */

 		UINT32 left;              /* 16 */
@@ -89,12 +89,12 @@ extern "C"
 	struct rdp_pointer
 	{
 		size_t size;                      /* 0 */
-		pPointer_New New;                 /* 1 */
+		WINPR_ATTR_NODISCARD pPointer_New New; /* 1 */
 		pPointer_Free Free;               /* 2 */
-		pPointer_Set Set;                 /* 3 */
-		pPointer_SetNull SetNull;         /* 4*/
-		pPointer_SetDefault SetDefault;   /* 5 */
-		pPointer_SetPosition SetPosition; /* 6 */
+		WINPR_ATTR_NODISCARD pPointer_Set Set;                 /* 3 */
+		WINPR_ATTR_NODISCARD pPointer_SetNull SetNull;         /* 4*/
+		WINPR_ATTR_NODISCARD pPointer_SetDefault SetDefault;   /* 5 */
+		WINPR_ATTR_NODISCARD pPointer_SetPosition SetPosition; /* 6 */
 		UINT32 paddingA[16 - 7];          /* 7 */

 		UINT32 xPos;              /* 16 */
@@ -127,12 +127,12 @@ extern "C"
 	struct rdp_glyph
 	{
 		size_t size;                /* 0 */
-		pGlyph_New New;             /* 1 */
+		WINPR_ATTR_NODISCARD pGlyph_New New; /* 1 */
 		pGlyph_Free Free;           /* 2 */
-		pGlyph_Draw Draw;           /* 3 */
-		pGlyph_BeginDraw BeginDraw; /* 4 */
-		pGlyph_EndDraw EndDraw;     /* 5 */
-		pGlyph_SetBounds SetBounds; /* 6 */
+		WINPR_ATTR_NODISCARD pGlyph_Draw Draw;           /* 3 */
+		WINPR_ATTR_NODISCARD pGlyph_BeginDraw BeginDraw; /* 4 */
+		WINPR_ATTR_NODISCARD pGlyph_EndDraw EndDraw;     /* 5 */
+		WINPR_ATTR_NODISCARD pGlyph_SetBounds SetBounds; /* 6 */
 		UINT32 paddingA[16 - 7];    /* 7 */

 		INT32 x;                  /* 16 */
--- a/include/freerdp/heartbeat.h
+++ b/include/freerdp/heartbeat.h
@@ -34,7 +34,7 @@ extern "C"

 	struct rdp_heartbeat
 	{
-		pServerHeartbeat ServerHeartbeat;
+		WINPR_ATTR_NODISCARD pServerHeartbeat ServerHeartbeat;
 	};

 	FREERDP_API BOOL freerdp_heartbeat_send_heartbeat_pdu(freerdp_peer* peer, BYTE period,
--- a/include/freerdp/input.h
+++ b/include/freerdp/input.h
@@ -90,15 +90,15 @@ extern "C"
 		void* param1;            /* 1 */
 		UINT32 paddingA[16 - 2]; /* 2 */

-		pSynchronizeEvent SynchronizeEvent;         /* 16 */
-		pKeyboardEvent KeyboardEvent;               /* 17 */
-		pUnicodeKeyboardEvent UnicodeKeyboardEvent; /* 18 */
-		pMouseEvent MouseEvent;                     /* 19 */
-		pExtendedMouseEvent ExtendedMouseEvent;     /* 20 */
-		pFocusInEvent FocusInEvent;                 /*21 */
-		pKeyboardPauseEvent KeyboardPauseEvent;     /* 22 */
-		pRelMouseEvent RelMouseEvent;               /* 23 */
-		pQoEEvent QoEEvent;                         /* 24 */
+		WINPR_ATTR_NODISCARD pSynchronizeEvent SynchronizeEvent;         /* 16 */
+		WINPR_ATTR_NODISCARD pKeyboardEvent KeyboardEvent;               /* 17 */
+		WINPR_ATTR_NODISCARD pUnicodeKeyboardEvent UnicodeKeyboardEvent; /* 18 */
+		WINPR_ATTR_NODISCARD pMouseEvent MouseEvent;                     /* 19 */
+		WINPR_ATTR_NODISCARD pExtendedMouseEvent ExtendedMouseEvent;     /* 20 */
+		WINPR_ATTR_NODISCARD pFocusInEvent FocusInEvent;                 /*21 */
+		WINPR_ATTR_NODISCARD pKeyboardPauseEvent KeyboardPauseEvent;     /* 22 */
+		WINPR_ATTR_NODISCARD pRelMouseEvent RelMouseEvent;               /* 23 */
+		WINPR_ATTR_NODISCARD pQoEEvent QoEEvent;                         /* 24 */

 		UINT32 paddingB[32 - 25]; /* 25 */
 	};
--- a/include/freerdp/listener.h
+++ b/include/freerdp/listener.h
@@ -56,22 +56,22 @@ extern "C"
 		void* param3;
 		void* param4;

-		psListenerOpen Open;
-		psListenerOpenLocal OpenLocal;
+		WINPR_ATTR_NODISCARD psListenerOpen Open;
+		WINPR_ATTR_NODISCARD psListenerOpenLocal OpenLocal;
 #if defined(WITH_FREERDP_DEPRECATED)
 		WINPR_DEPRECATED_VAR("Use rdp_freerdp_listener::GetEventHandles instead",
-		                     psListenerGetFileDescriptor GetFileDescriptor;)
+		                     WINPR_ATTR_NODISCARD psListenerGetFileDescriptor GetFileDescriptor;)
 #else
 	void* reserved;
 #endif
-		psListenerGetEventHandles GetEventHandles;
-		psListenerCheckFileDescriptor CheckFileDescriptor;
+		WINPR_ATTR_NODISCARD psListenerGetEventHandles GetEventHandles;
+		WINPR_ATTR_NODISCARD psListenerCheckFileDescriptor CheckFileDescriptor;
 		psListenerClose Close;

-		psPeerAccepted PeerAccepted;
-		psListenerOpenFromSocket OpenFromSocket;
+		WINPR_ATTR_NODISCARD psPeerAccepted PeerAccepted;
+		WINPR_ATTR_NODISCARD psListenerOpenFromSocket OpenFromSocket;

-		psListenerCheckFileDescriptor CheckPeerAcceptRestrictions;
+		WINPR_ATTR_NODISCARD psListenerCheckFileDescriptor CheckPeerAcceptRestrictions;
 	};

 	FREERDP_API void freerdp_listener_free(freerdp_listener* instance);
--- a/include/freerdp/peer.h
+++ b/include/freerdp/peer.h
@@ -140,38 +140,39 @@ extern "C"

 		ALIGN64 void* ContextExtra;
 		ALIGN64 size_t ContextSize;
-		ALIGN64 psPeerContextNew ContextNew;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerContextNew ContextNew;
 		ALIGN64 psPeerContextFree ContextFree;

-		ALIGN64 psPeerInitialize Initialize;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerInitialize Initialize;
 #if defined(WITH_FREERDP_DEPRECATED)
 		WINPR_DEPRECATED_VAR("Use freerdp_peer::GetEventHandle instead",
-		                     ALIGN64 psPeerGetFileDescriptor GetFileDescriptor;)
+		                     ALIGN64 WINPR_ATTR_NODISCARD psPeerGetFileDescriptor
+		                         GetFileDescriptor;)
 #else
 	UINT64 reserved;
 #endif
-		ALIGN64 psPeerGetEventHandle GetEventHandle;
-		ALIGN64 psPeerGetReceiveEventHandle GetReceiveEventHandle;
-		ALIGN64 psPeerCheckFileDescriptor CheckFileDescriptor;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerGetEventHandle GetEventHandle;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerGetReceiveEventHandle GetReceiveEventHandle;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerCheckFileDescriptor CheckFileDescriptor;
 		ALIGN64 psPeerClose Close;
 		ALIGN64 psPeerDisconnect Disconnect;

-		ALIGN64 psPeerCapabilities Capabilities;
-		ALIGN64 psPeerPostConnect PostConnect;
-		ALIGN64 psPeerActivate Activate;
-		ALIGN64 psPeerLogon Logon;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerCapabilities Capabilities;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerPostConnect PostConnect;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerActivate Activate;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerLogon Logon;

-		ALIGN64 psPeerSendServerRedirection SendServerRedirection;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerSendServerRedirection SendServerRedirection;

-		ALIGN64 psPeerSendChannelData SendChannelData;
-		ALIGN64 psPeerReceiveChannelData ReceiveChannelData;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerSendChannelData SendChannelData;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerReceiveChannelData ReceiveChannelData;

-		ALIGN64 psPeerVirtualChannelOpen VirtualChannelOpen;
-		ALIGN64 psPeerVirtualChannelClose VirtualChannelClose;
-		ALIGN64 psPeerVirtualChannelRead VirtualChannelRead;
-		ALIGN64 psPeerVirtualChannelWrite VirtualChannelWrite;
-		ALIGN64 psPeerVirtualChannelGetData VirtualChannelGetData;
-		ALIGN64 psPeerVirtualChannelSetData VirtualChannelSetData;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerVirtualChannelOpen VirtualChannelOpen;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerVirtualChannelClose VirtualChannelClose;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerVirtualChannelRead VirtualChannelRead;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerVirtualChannelWrite VirtualChannelWrite;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerVirtualChannelGetData VirtualChannelGetData;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerVirtualChannelSetData VirtualChannelSetData;

 		ALIGN64 int pId;
 		ALIGN64 UINT32 ack_frame_id;
@@ -181,21 +182,21 @@ extern "C"
 		ALIGN64 BOOL authenticated;
 		ALIGN64 SEC_WINNT_AUTH_IDENTITY identity;

-		ALIGN64 psPeerIsWriteBlocked IsWriteBlocked;
-		ALIGN64 psPeerDrainOutputBuffer DrainOutputBuffer;
-		ALIGN64 psPeerHasMoreToRead HasMoreToRead;
-		ALIGN64 psPeerGetEventHandles GetEventHandles;
-		ALIGN64 psPeerAdjustMonitorsLayout AdjustMonitorsLayout;
-		ALIGN64 psPeerClientCapabilities ClientCapabilities;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerIsWriteBlocked IsWriteBlocked;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerDrainOutputBuffer DrainOutputBuffer;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerHasMoreToRead HasMoreToRead;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerGetEventHandles GetEventHandles;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerAdjustMonitorsLayout AdjustMonitorsLayout;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerClientCapabilities ClientCapabilities;
 #if defined(WITH_FREERDP_DEPRECATED)
 		WINPR_DEPRECATED_VAR("Use freerdp_peer::SspiNtlmHashCallback instead",
-		                     ALIGN64 psPeerComputeNtlmHash ComputeNtlmHash;)
+		                     ALIGN64 WINPR_ATTR_NODISCARD psPeerComputeNtlmHash ComputeNtlmHash;)
 #else
 	UINT64 reserved2;
 #endif
-		ALIGN64 psPeerLicenseCallback LicenseCallback;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerLicenseCallback LicenseCallback;

-		ALIGN64 psPeerSendChannelPacket SendChannelPacket;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerSendChannelPacket SendChannelPacket;

 		/**
 		 * @brief SetState Function pointer allowing to manually set the state of the
@@ -207,15 +208,15 @@ extern "C"
 		 *
 		 * \note Must be called after \b Initialize as that also modifies the state.
 		 */
-		ALIGN64 psPeerSetState SetState;
-		ALIGN64 psPeerReachedState ReachedState;
-		ALIGN64 psSspiNtlmHashCallback SspiNtlmHashCallback;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerSetState SetState;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerReachedState ReachedState;
+		ALIGN64 WINPR_ATTR_NODISCARD psSspiNtlmHashCallback SspiNtlmHashCallback;
 		/**
 		 * @brief RemoteCredentials Function pointer that will be called when remote
 		 * credentials guard are used by the peer and we receive the logonCreds (kerberos)
 		 * and supplementary creds (NTLM).
 		 */
-		ALIGN64 psPeerRemoteCredentials RemoteCredentials;
+		ALIGN64 WINPR_ATTR_NODISCARD psPeerRemoteCredentials RemoteCredentials;
 	};

 	FREERDP_API void freerdp_peer_context_free(freerdp_peer* client);
--- a/include/freerdp/pointer.h
+++ b/include/freerdp/pointer.h
@@ -101,12 +101,12 @@ extern "C"
 		rdpContext* context;     /* 0 */
 		UINT32 paddingA[16 - 1]; /* 1 */

-		pPointerPosition PointerPosition; /* 16 */
-		pPointerSystem PointerSystem;     /* 17 */
-		pPointerColor PointerColor;       /* 18 */
-		pPointerNew PointerNew;           /* 19 */
-		pPointerCached PointerCached;     /* 20 */
-		pPointerLarge PointerLarge;       /* 21 */
+		WINPR_ATTR_NODISCARD pPointerPosition PointerPosition; /* 16 */
+		WINPR_ATTR_NODISCARD pPointerSystem PointerSystem;     /* 17 */
+		WINPR_ATTR_NODISCARD pPointerColor PointerColor;       /* 18 */
+		WINPR_ATTR_NODISCARD pPointerNew PointerNew;           /* 19 */
+		WINPR_ATTR_NODISCARD pPointerCached PointerCached;     /* 20 */
+		WINPR_ATTR_NODISCARD pPointerLarge PointerLarge;       /* 21 */
 		UINT32 paddingB[32 - 22];         /* 22 */
 	};
 	typedef struct rdp_pointer_update rdpPointerUpdate;
--- a/include/freerdp/primary.h
+++ b/include/freerdp/primary.h
@@ -423,9 +423,9 @@ typedef BOOL (*pMultiDstBlt)(rdpContext* context, const MULTI_DSTBLT_ORDER* mult
 typedef BOOL (*pMultiPatBlt)(rdpContext* context, const MULTI_PATBLT_ORDER* multi_patblt);
 typedef BOOL (*pMultiScrBlt)(rdpContext* context, const MULTI_SCRBLT_ORDER* multi_scrblt);
 typedef BOOL (*pMultiOpaqueRect)(rdpContext* context,
-                                 const MULTI_OPAQUE_RECT_ORDER* multi_opaque_rect);
+	                             const MULTI_OPAQUE_RECT_ORDER* multi_opaque_rect);
 typedef BOOL (*pMultiDrawNineGrid)(rdpContext* context,
-                                   const MULTI_DRAW_NINE_GRID_ORDER* multi_draw_nine_grid);
+	                               const MULTI_DRAW_NINE_GRID_ORDER* multi_draw_nine_grid);
 typedef BOOL (*pLineTo)(rdpContext* context, const LINE_TO_ORDER* line_to);
 typedef BOOL (*pPolyline)(rdpContext* context, const POLYLINE_ORDER* polyline);
 typedef BOOL (*pMemBlt)(rdpContext* context, MEMBLT_ORDER* memblt);
@@ -439,37 +439,37 @@ typedef BOOL (*pPolygonCB)(rdpContext* context, POLYGON_CB_ORDER* polygon_cb);
 typedef BOOL (*pEllipseSC)(rdpContext* context, const ELLIPSE_SC_ORDER* ellipse_sc);
 typedef BOOL (*pEllipseCB)(rdpContext* context, const ELLIPSE_CB_ORDER* ellipse_cb);
 typedef BOOL (*pOrderInfo)(rdpContext* context, const ORDER_INFO* order_info,
-                           const char* order_name);
+	                       const char* order_name);

 struct rdp_primary_update
 {
 	rdpContext* context;     /* 0 */
 	UINT32 paddingA[16 - 1]; /* 1 */

-	pDstBlt DstBlt;                       /* 16 */
-	pPatBlt PatBlt;                       /* 17 */
-	pScrBlt ScrBlt;                       /* 18 */
-	pOpaqueRect OpaqueRect;               /* 19 */
-	pDrawNineGrid DrawNineGrid;           /* 20 */
-	pMultiDstBlt MultiDstBlt;             /* 21 */
-	pMultiPatBlt MultiPatBlt;             /* 22 */
-	pMultiScrBlt MultiScrBlt;             /* 23 */
-	pMultiOpaqueRect MultiOpaqueRect;     /* 24 */
-	pMultiDrawNineGrid MultiDrawNineGrid; /* 25 */
-	pLineTo LineTo;                       /* 26 */
-	pPolyline Polyline;                   /* 27 */
-	pMemBlt MemBlt;                       /* 28 */
-	pMem3Blt Mem3Blt;                     /* 29 */
-	pSaveBitmap SaveBitmap;               /* 30 */
-	pGlyphIndex GlyphIndex;               /* 31 */
-	pFastIndex FastIndex;                 /* 32 */
-	pFastGlyph FastGlyph;                 /* 33 */
-	pPolygonSC PolygonSC;                 /* 34 */
-	pPolygonCB PolygonCB;                 /* 35 */
-	pEllipseSC EllipseSC;                 /* 36 */
-	pEllipseCB EllipseCB;                 /* 37 */
-	/* Statistics callback */
-	pOrderInfo OrderInfo;     /* 38 */
+	WINPR_ATTR_NODISCARD pDstBlt DstBlt;                       /* 16 */
+	WINPR_ATTR_NODISCARD pPatBlt PatBlt;                       /* 17 */
+	WINPR_ATTR_NODISCARD pScrBlt ScrBlt;                       /* 18 */
+	WINPR_ATTR_NODISCARD pOpaqueRect OpaqueRect;               /* 19 */
+	WINPR_ATTR_NODISCARD pDrawNineGrid DrawNineGrid;           /* 20 */
+	WINPR_ATTR_NODISCARD pMultiDstBlt MultiDstBlt;             /* 21 */
+	WINPR_ATTR_NODISCARD pMultiPatBlt MultiPatBlt;             /* 22 */
+	WINPR_ATTR_NODISCARD pMultiScrBlt MultiScrBlt;             /* 23 */
+	WINPR_ATTR_NODISCARD pMultiOpaqueRect MultiOpaqueRect;     /* 24 */
+	WINPR_ATTR_NODISCARD pMultiDrawNineGrid MultiDrawNineGrid; /* 25 */
+	WINPR_ATTR_NODISCARD pLineTo LineTo;                       /* 26 */
+	WINPR_ATTR_NODISCARD pPolyline Polyline;                   /* 27 */
+	WINPR_ATTR_NODISCARD pMemBlt MemBlt;                       /* 28 */
+	WINPR_ATTR_NODISCARD pMem3Blt Mem3Blt;                     /* 29 */
+	WINPR_ATTR_NODISCARD pSaveBitmap SaveBitmap;               /* 30 */
+	WINPR_ATTR_NODISCARD pGlyphIndex GlyphIndex;               /* 31 */
+	WINPR_ATTR_NODISCARD pFastIndex FastIndex;                 /* 32 */
+	WINPR_ATTR_NODISCARD pFastGlyph FastGlyph;                 /* 33 */
+	WINPR_ATTR_NODISCARD pPolygonSC PolygonSC;                 /* 34 */
+	WINPR_ATTR_NODISCARD pPolygonCB PolygonCB;                 /* 35 */
+	WINPR_ATTR_NODISCARD pEllipseSC EllipseSC;                 /* 36 */
+	WINPR_ATTR_NODISCARD pEllipseCB EllipseCB;                 /* 37 */
+		                                                       /* Statistics callback */
+	WINPR_ATTR_NODISCARD pOrderInfo OrderInfo;                 /* 38 */
 	UINT32 paddingB[48 - 39]; /* 39 */
 };
 typedef struct rdp_primary_update rdpPrimaryUpdate;
--- a/include/freerdp/primitives.h
+++ b/include/freerdp/primitives.h
@@ -254,44 +254,44 @@ typedef fn_orC_32u_t __orC_32u_t;
 typedef struct
 {
 	/* Memory-to-memory copy routines */
-	fn_copy_t copy;                 /* memcpy/memmove, basically */
-	fn_copy_8u_t copy_8u;           /* more strongly typed */
-	fn_copy_8u_AC4r_t copy_8u_AC4r; /* pixel copy function */
-	/* Memory setting routines */
-	fn_set_8u_t set_8u; /* memset, basically */
-	fn_set_32s_t set_32s;
-	fn_set_32u_t set_32u;
-	fn_zero_t zero; /* bzero or faster */
-	/* Arithmetic functions */
-	fn_add_16s_t add_16s;
+	WINPR_ATTR_NODISCARD fn_copy_t copy;                 /* memcpy/memmove, basically */
+	WINPR_ATTR_NODISCARD fn_copy_8u_t copy_8u;           /* more strongly typed */
+	WINPR_ATTR_NODISCARD fn_copy_8u_AC4r_t copy_8u_AC4r; /* pixel copy function */
+		                                                 /* Memory setting routines */
+	WINPR_ATTR_NODISCARD fn_set_8u_t set_8u;             /* memset, basically */
+	WINPR_ATTR_NODISCARD fn_set_32s_t set_32s;
+	WINPR_ATTR_NODISCARD fn_set_32u_t set_32u;
+	WINPR_ATTR_NODISCARD fn_zero_t zero; /* bzero or faster */
+		                                 /* Arithmetic functions */
+	WINPR_ATTR_NODISCARD fn_add_16s_t add_16s;
 	/* And/or */
-	fn_andC_32u_t andC_32u;
-	fn_orC_32u_t orC_32u;
+	WINPR_ATTR_NODISCARD fn_andC_32u_t andC_32u;
+	WINPR_ATTR_NODISCARD fn_orC_32u_t orC_32u;
 	/* Shifts */
-	fn_lShiftC_16s_t lShiftC_16s;
-	fn_lShiftC_16u_t lShiftC_16u;
-	fn_rShiftC_16s_t rShiftC_16s;
-	fn_rShiftC_16u_t rShiftC_16u;
-	fn_shiftC_16s_t shiftC_16s;
-	fn_shiftC_16u_t shiftC_16u;
+	WINPR_ATTR_NODISCARD fn_lShiftC_16s_t lShiftC_16s;
+	WINPR_ATTR_NODISCARD fn_lShiftC_16u_t lShiftC_16u;
+	WINPR_ATTR_NODISCARD fn_rShiftC_16s_t rShiftC_16s;
+	WINPR_ATTR_NODISCARD fn_rShiftC_16u_t rShiftC_16u;
+	WINPR_ATTR_NODISCARD fn_shiftC_16s_t shiftC_16s;
+	WINPR_ATTR_NODISCARD fn_shiftC_16u_t shiftC_16u;
 	/* Alpha Composition */
-	fn_alphaComp_argb_t alphaComp_argb;
+	WINPR_ATTR_NODISCARD fn_alphaComp_argb_t alphaComp_argb;
 	/* Sign */
-	fn_sign_16s_t sign_16s;
+	WINPR_ATTR_NODISCARD fn_sign_16s_t sign_16s;
 	/* Color conversions */
-	fn_yCbCrToRGB_16s8u_P3AC4R_t yCbCrToRGB_16s8u_P3AC4R;
-	fn_yCbCrToRGB_16s16s_P3P3_t yCbCrToRGB_16s16s_P3P3;
-	fn_RGBToYCbCr_16s16s_P3P3_t RGBToYCbCr_16s16s_P3P3;
-	fn_RGBToRGB_16s8u_P3AC4R_t RGBToRGB_16s8u_P3AC4R;
-	fn_YCoCgToRGB_8u_AC4R_t YCoCgToRGB_8u_AC4R;
-	fn_YUV420ToRGB_8u_P3AC4R_t YUV420ToRGB_8u_P3AC4R;
-	fn_RGBToYUV420_8u_P3AC4R_t RGBToYUV420_8u_P3AC4R;
-	fn_RGBToYUV444_8u_P3AC4R_t RGBToYUV444_8u_P3AC4R;
-	fn_YUV420CombineToYUV444_t YUV420CombineToYUV444;
-	fn_YUV444SplitToYUV420_t YUV444SplitToYUV420;
-	fn_YUV444ToRGB_8u_P3AC4R_t YUV444ToRGB_8u_P3AC4R;
-	fn_RGBToAVC444YUV_t RGBToAVC444YUV;
-	fn_RGBToAVC444YUV_t RGBToAVC444YUVv2;
+	WINPR_ATTR_NODISCARD fn_yCbCrToRGB_16s8u_P3AC4R_t yCbCrToRGB_16s8u_P3AC4R;
+	WINPR_ATTR_NODISCARD fn_yCbCrToRGB_16s16s_P3P3_t yCbCrToRGB_16s16s_P3P3;
+	WINPR_ATTR_NODISCARD fn_RGBToYCbCr_16s16s_P3P3_t RGBToYCbCr_16s16s_P3P3;
+	WINPR_ATTR_NODISCARD fn_RGBToRGB_16s8u_P3AC4R_t RGBToRGB_16s8u_P3AC4R;
+	WINPR_ATTR_NODISCARD fn_YCoCgToRGB_8u_AC4R_t YCoCgToRGB_8u_AC4R;
+	WINPR_ATTR_NODISCARD fn_YUV420ToRGB_8u_P3AC4R_t YUV420ToRGB_8u_P3AC4R;
+	WINPR_ATTR_NODISCARD fn_RGBToYUV420_8u_P3AC4R_t RGBToYUV420_8u_P3AC4R;
+	WINPR_ATTR_NODISCARD fn_RGBToYUV444_8u_P3AC4R_t RGBToYUV444_8u_P3AC4R;
+	WINPR_ATTR_NODISCARD fn_YUV420CombineToYUV444_t YUV420CombineToYUV444;
+	WINPR_ATTR_NODISCARD fn_YUV444SplitToYUV420_t YUV444SplitToYUV420;
+	WINPR_ATTR_NODISCARD fn_YUV444ToRGB_8u_P3AC4R_t YUV444ToRGB_8u_P3AC4R;
+	WINPR_ATTR_NODISCARD fn_RGBToAVC444YUV_t RGBToAVC444YUV;
+	WINPR_ATTR_NODISCARD fn_RGBToAVC444YUV_t RGBToAVC444YUVv2;
 	/* flags */
 	DWORD flags;
 	primitives_uninit_t uninit;
@@ -299,9 +299,9 @@ typedef struct
 	/** \brief Do vecotor addition, store result in both input buffers
 	 *  pSrcDst1 = pSrcDst2 = pSrcDst1  + pSrcDst2
 	 */
-	fn_add_16s_inplace_t add_16s_inplace;         /** @since version 3.6.0 */
-	fn_lShiftC_16s_inplace_t lShiftC_16s_inplace; /** @since version 3.6.0 */
-	fn_copy_no_overlap_t copy_no_overlap;         /** @since version 3.6.0 */
+	WINPR_ATTR_NODISCARD fn_add_16s_inplace_t add_16s_inplace;         /** @since version 3.6.0 */
+	WINPR_ATTR_NODISCARD fn_lShiftC_16s_inplace_t lShiftC_16s_inplace; /** @since version 3.6.0 */
+	WINPR_ATTR_NODISCARD fn_copy_no_overlap_t copy_no_overlap;         /** @since version 3.6.0 */
 } primitives_t;

 typedef enum
--- a/include/freerdp/secondary.h
+++ b/include/freerdp/secondary.h
@@ -164,28 +164,28 @@ typedef BOOL (*pCacheBitmap)(rdpContext* context, const CACHE_BITMAP_ORDER* cach
 typedef BOOL (*pCacheBitmapV2)(rdpContext* context, CACHE_BITMAP_V2_ORDER* cache_bitmap_v2_order);
 typedef BOOL (*pCacheBitmapV3)(rdpContext* context, CACHE_BITMAP_V3_ORDER* cache_bitmap_v3_order);
 typedef BOOL (*pCacheColorTable)(rdpContext* context,
-                                 const CACHE_COLOR_TABLE_ORDER* cache_color_table_order);
+	                             const CACHE_COLOR_TABLE_ORDER* cache_color_table_order);
 typedef BOOL (*pCacheGlyph)(rdpContext* context, const CACHE_GLYPH_ORDER* cache_glyph_order);
 typedef BOOL (*pCacheGlyphV2)(rdpContext* context,
-                              const CACHE_GLYPH_V2_ORDER* cache_glyph_v2_order);
+	                          const CACHE_GLYPH_V2_ORDER* cache_glyph_v2_order);
 typedef BOOL (*pCacheBrush)(rdpContext* context, const CACHE_BRUSH_ORDER* cache_brush_order);
 typedef BOOL (*pCacheOrderInfo)(rdpContext* context, INT16 orderLength, UINT16 extraFlags,
-                                UINT8 orderType, const char* orderName);
+	                            UINT8 orderType, const char* orderName);

 struct rdp_secondary_update
 {
 	rdpContext* context;     /* 0 */
 	UINT32 paddingA[16 - 1]; /* 1 */

-	pCacheBitmap CacheBitmap;         /* 16 */
-	pCacheBitmapV2 CacheBitmapV2;     /* 17 */
-	pCacheBitmapV3 CacheBitmapV3;     /* 18 */
-	pCacheColorTable CacheColorTable; /* 19 */
-	pCacheGlyph CacheGlyph;           /* 20 */
-	pCacheGlyphV2 CacheGlyphV2;       /* 21 */
-	pCacheBrush CacheBrush;           /* 22 */
-	/* Statistics callback */
-	pCacheOrderInfo CacheOrderInfo; /* 23 */
+	WINPR_ATTR_NODISCARD pCacheBitmap CacheBitmap;         /* 16 */
+	WINPR_ATTR_NODISCARD pCacheBitmapV2 CacheBitmapV2;     /* 17 */
+	WINPR_ATTR_NODISCARD pCacheBitmapV3 CacheBitmapV3;     /* 18 */
+	WINPR_ATTR_NODISCARD pCacheColorTable CacheColorTable; /* 19 */
+	WINPR_ATTR_NODISCARD pCacheGlyph CacheGlyph;           /* 20 */
+	WINPR_ATTR_NODISCARD pCacheGlyphV2 CacheGlyphV2;       /* 21 */
+	WINPR_ATTR_NODISCARD pCacheBrush CacheBrush;           /* 22 */
+		                                                   /* Statistics callback */
+	WINPR_ATTR_NODISCARD pCacheOrderInfo CacheOrderInfo;   /* 23 */
 	UINT32 paddingE[32 - 24];       /* 24 */
 };
 typedef struct rdp_secondary_update rdpSecondaryUpdate;
--- a/include/freerdp/server/ainput.h
+++ b/include/freerdp/server/ainput.h
@@ -65,7 +65,7 @@ extern "C"
 		/**
 		 * Open the ainput channel.
 		 */
-		psAInputServerOpen Open;
+		WINPR_ATTR_NODISCARD psAInputServerOpen Open;

 		/**
 		 * Optional: Set thread handling.
@@ -74,42 +74,42 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psAInputServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psAInputServerInitialize Initialize;

 		/**
 		 * @brief Poll When externalThread=TRUE call periodically from your main loop.
 		 * if externalThread=FALSE do not call.
 		 */
-		psAInputServerPoll Poll;
+		WINPR_ATTR_NODISCARD psAInputServerPoll Poll;

 		/**
 		 * @brief Poll When externalThread=TRUE call to get a handle to wait for events.
 		 * Will return FALSE until the handle is available.
 		 */
-		psAInputServerChannelHandle ChannelHandle;
+		WINPR_ATTR_NODISCARD psAInputServerChannelHandle ChannelHandle;

 		/**
 		 * Close the ainput channel.
 		 */
-		psAInputServerClose Close;
+		WINPR_ATTR_NODISCARD psAInputServerClose Close;
 		/**
 		 * Status of the ainput channel.
 		 */
-		psAInputServerIsOpen IsOpen;
+		WINPR_ATTR_NODISCARD psAInputServerIsOpen IsOpen;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Receive ainput mouse event PDU.
 		 */
-		psAInputServerMouseEvent MouseEvent;
+		WINPR_ATTR_NODISCARD psAInputServerMouseEvent MouseEvent;

 		rdpContext* rdpcontext;

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psAInputChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psAInputChannelIdAssigned ChannelIdAssigned;
 	};

 	FREERDP_API void ainput_server_context_free(ainput_server_context* context);
--- a/include/freerdp/server/audin.h
+++ b/include/freerdp/server/audin.h
@@ -76,17 +76,17 @@ extern "C"
 		/**
 		 * Open the audio input channel.
 		 */
-		psAudinServerChannelOpen Open;
+		WINPR_ATTR_NODISCARD psAudinServerChannelOpen Open;

 		/**
 		 * Check, whether the audio input channel thread was created
 		 */
-		psAudinServerChannelIsOpen IsOpen;
+		WINPR_ATTR_NODISCARD psAudinServerChannelIsOpen IsOpen;

 		/**
 		 * Close the audio input channel.
 		 */
-		psAudinServerChannelClose Close;
+		WINPR_ATTR_NODISCARD psAudinServerChannelClose Close;

 		/**
 		 * For the following server to client PDUs,
@@ -96,59 +96,59 @@ extern "C"
 		/**
 		 * Send a Version PDU.
 		 */
-		psAudinServerVersion SendVersion;
+		WINPR_ATTR_NODISCARD psAudinServerVersion SendVersion;

 		/**
 		 * Send a Sound Formats PDU.
 		 */
-		psAudinServerFormats SendFormats;
+		WINPR_ATTR_NODISCARD psAudinServerFormats SendFormats;

 		/**
 		 * Send an Open PDU.
 		 */
-		psAudinServerOpen SendOpen;
+		WINPR_ATTR_NODISCARD psAudinServerOpen SendOpen;

 		/**
 		 * Send a Format Change PDU.
 		 */
-		psAudinServerFormatChange SendFormatChange;
+		WINPR_ATTR_NODISCARD psAudinServerFormatChange SendFormatChange;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psAudinServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psAudinServerChannelIdAssigned ChannelIdAssigned;

 		/*
 		 * Callback for the Version PDU.
 		 */
-		psAudinServerVersion ReceiveVersion;
+		WINPR_ATTR_NODISCARD psAudinServerVersion ReceiveVersion;

 		/*
 		 * Callback for the Sound Formats PDU.
 		 */
-		psAudinServerFormats ReceiveFormats;
+		WINPR_ATTR_NODISCARD psAudinServerFormats ReceiveFormats;

 		/*
 		 * Callback for the Open Reply PDU.
 		 */
-		psAudinServerOpenReply OpenReply;
+		WINPR_ATTR_NODISCARD psAudinServerOpenReply OpenReply;

 		/*
 		 * Callback for the Incoming Data PDU.
 		 */
-		psAudinServerIncomingData IncomingData;
+		WINPR_ATTR_NODISCARD psAudinServerIncomingData IncomingData;

 		/*
 		 * Callback for the Data PDU.
 		 */
-		psAudinServerData Data;
+		WINPR_ATTR_NODISCARD psAudinServerData Data;

 		/*
 		 * Callback for the Format Change PDU.
 		 */
-		psAudinServerFormatChange ReceiveFormatChange;
+		WINPR_ATTR_NODISCARD psAudinServerFormatChange ReceiveFormatChange;

 		rdpContext* rdpcontext;
 	};
--- a/include/freerdp/server/cliprdr.h
+++ b/include/freerdp/server/cliprdr.h
@@ -100,33 +100,33 @@ extern "C"
 		BOOL fileClipNoFilePaths;
 		BOOL canLockClipData;

-		psCliprdrOpen Open;
+		WINPR_ATTR_NODISCARD psCliprdrOpen Open;
 		psCliprdrClose Close;
-		psCliprdrStart Start;
+		WINPR_ATTR_NODISCARD psCliprdrStart Start;
 		psCliprdrStop Stop;
-		psCliprdrGetEventHandle GetEventHandle;
-		psCliprdrCheckEventHandle CheckEventHandle;
+		WINPR_ATTR_NODISCARD psCliprdrGetEventHandle GetEventHandle;
+		WINPR_ATTR_NODISCARD psCliprdrCheckEventHandle CheckEventHandle;

-		psCliprdrServerCapabilities ServerCapabilities;
-		psCliprdrClientCapabilities ClientCapabilities;
-		psCliprdrMonitorReady MonitorReady;
-		psCliprdrTempDirectory TempDirectory;
-		psCliprdrClientFormatList ClientFormatList;
-		psCliprdrServerFormatList ServerFormatList;
-		psCliprdrClientFormatListResponse ClientFormatListResponse;
-		psCliprdrServerFormatListResponse ServerFormatListResponse;
-		psCliprdrClientLockClipboardData ClientLockClipboardData;
-		psCliprdrServerLockClipboardData ServerLockClipboardData;
-		psCliprdrClientUnlockClipboardData ClientUnlockClipboardData;
-		psCliprdrServerUnlockClipboardData ServerUnlockClipboardData;
-		psCliprdrClientFormatDataRequest ClientFormatDataRequest;
-		psCliprdrServerFormatDataRequest ServerFormatDataRequest;
-		psCliprdrClientFormatDataResponse ClientFormatDataResponse;
-		psCliprdrServerFormatDataResponse ServerFormatDataResponse;
-		psCliprdrClientFileContentsRequest ClientFileContentsRequest;
-		psCliprdrServerFileContentsRequest ServerFileContentsRequest;
-		psCliprdrClientFileContentsResponse ClientFileContentsResponse;
-		psCliprdrServerFileContentsResponse ServerFileContentsResponse;
+		WINPR_ATTR_NODISCARD psCliprdrServerCapabilities ServerCapabilities;
+		WINPR_ATTR_NODISCARD psCliprdrClientCapabilities ClientCapabilities;
+		WINPR_ATTR_NODISCARD psCliprdrMonitorReady MonitorReady;
+		WINPR_ATTR_NODISCARD psCliprdrTempDirectory TempDirectory;
+		WINPR_ATTR_NODISCARD psCliprdrClientFormatList ClientFormatList;
+		WINPR_ATTR_NODISCARD psCliprdrServerFormatList ServerFormatList;
+		WINPR_ATTR_NODISCARD psCliprdrClientFormatListResponse ClientFormatListResponse;
+		WINPR_ATTR_NODISCARD psCliprdrServerFormatListResponse ServerFormatListResponse;
+		WINPR_ATTR_NODISCARD psCliprdrClientLockClipboardData ClientLockClipboardData;
+		WINPR_ATTR_NODISCARD psCliprdrServerLockClipboardData ServerLockClipboardData;
+		WINPR_ATTR_NODISCARD psCliprdrClientUnlockClipboardData ClientUnlockClipboardData;
+		WINPR_ATTR_NODISCARD psCliprdrServerUnlockClipboardData ServerUnlockClipboardData;
+		WINPR_ATTR_NODISCARD psCliprdrClientFormatDataRequest ClientFormatDataRequest;
+		WINPR_ATTR_NODISCARD psCliprdrServerFormatDataRequest ServerFormatDataRequest;
+		WINPR_ATTR_NODISCARD psCliprdrClientFormatDataResponse ClientFormatDataResponse;
+		WINPR_ATTR_NODISCARD psCliprdrServerFormatDataResponse ServerFormatDataResponse;
+		WINPR_ATTR_NODISCARD psCliprdrClientFileContentsRequest ClientFileContentsRequest;
+		WINPR_ATTR_NODISCARD psCliprdrServerFileContentsRequest ServerFileContentsRequest;
+		WINPR_ATTR_NODISCARD psCliprdrClientFileContentsResponse ClientFileContentsResponse;
+		WINPR_ATTR_NODISCARD psCliprdrServerFileContentsResponse ServerFileContentsResponse;

 		rdpContext* rdpcontext;
 		BOOL autoInitializationSequence;
--- a/include/freerdp/server/disp.h
+++ b/include/freerdp/server/disp.h
@@ -51,11 +51,11 @@ extern "C"
 		UINT32 MaxMonitorAreaFactorA;
 		UINT32 MaxMonitorAreaFactorB;

-		psDispOpen Open;
-		psDispClose Close;
+		WINPR_ATTR_NODISCARD psDispOpen Open;
+		WINPR_ATTR_NODISCARD psDispClose Close;

-		psDispMonitorLayout DispMonitorLayout;
-		psDispCaps DisplayControlCaps;
+		WINPR_ATTR_NODISCARD psDispMonitorLayout DispMonitorLayout;
+		WINPR_ATTR_NODISCARD psDispCaps DisplayControlCaps;

 		DispServerPrivate* priv;
 		rdpContext* rdpcontext;
@@ -63,7 +63,7 @@ extern "C"
 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psDispChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psDispChannelIdAssigned ChannelIdAssigned;
 	};

 	FREERDP_API void disp_server_context_free(DispServerContext* context);
--- a/include/freerdp/server/drdynvc.h
+++ b/include/freerdp/server/drdynvc.h
@@ -45,7 +45,7 @@ extern "C"
 	{
 		HANDLE vcm;

-		psDrdynvcStart Start;
+		WINPR_ATTR_NODISCARD psDrdynvcStart Start;
 		psDrdynvcStop Stop;

 		DrdynvcServerPrivate* priv;
--- a/include/freerdp/server/echo.h
+++ b/include/freerdp/server/echo.h
@@ -62,25 +62,25 @@ extern "C"
 		/**
 		 * Open the echo channel.
 		 */
-		psEchoServerOpen Open;
+		WINPR_ATTR_NODISCARD psEchoServerOpen Open;
 		/**
 		 * Close the echo channel.
 		 */
-		psEchoServerClose Close;
+		WINPR_ATTR_NODISCARD psEchoServerClose Close;
 		/**
 		 * Send echo request PDU.
 		 */
-		psEchoServerRequest Request;
+		WINPR_ATTR_NODISCARD psEchoServerRequest Request;

 		/*** Callbacks registered by the server. ***/
 		/**
 		 * Indicate whether the channel is opened successfully.
 		 */
-		psEchoServerOpenResult OpenResult;
+		WINPR_ATTR_NODISCARD psEchoServerOpenResult OpenResult;
 		/**
 		 * Receive echo response PDU.
 		 */
-		psEchoServerResponse Response;
+		WINPR_ATTR_NODISCARD psEchoServerResponse Response;

 		rdpContext* rdpcontext;

--- a/include/freerdp/server/encomsp.h
+++ b/include/freerdp/server/encomsp.h
@@ -72,20 +72,20 @@ extern "C"
 		HANDLE vcm;
 		void* custom;

-		psEncomspStart Start;
+		WINPR_ATTR_NODISCARD psEncomspStart Start;
 		psEncomspStop Stop;

-		psEncomspFilterUpdated FilterUpdated;
-		psEncomspApplicationCreated ApplicationCreated;
-		psEncomspApplicationRemoved ApplicationRemoved;
-		psEncomspWindowCreated WindowCreated;
-		psEncomspWindowRemoved WindowRemoved;
-		psEncomspShowWindow ShowWindow;
-		psEncomspParticipantCreated ParticipantCreated;
-		psEncomspParticipantRemoved ParticipantRemoved;
-		psEncomspChangeParticipantControlLevel ChangeParticipantControlLevel;
-		psEncomspGraphicsStreamPaused GraphicsStreamPaused;
-		psEncomspGraphicsStreamResumed GraphicsStreamResumed;
+		WINPR_ATTR_NODISCARD psEncomspFilterUpdated FilterUpdated;
+		WINPR_ATTR_NODISCARD psEncomspApplicationCreated ApplicationCreated;
+		WINPR_ATTR_NODISCARD psEncomspApplicationRemoved ApplicationRemoved;
+		WINPR_ATTR_NODISCARD psEncomspWindowCreated WindowCreated;
+		WINPR_ATTR_NODISCARD psEncomspWindowRemoved WindowRemoved;
+		WINPR_ATTR_NODISCARD psEncomspShowWindow ShowWindow;
+		WINPR_ATTR_NODISCARD psEncomspParticipantCreated ParticipantCreated;
+		WINPR_ATTR_NODISCARD psEncomspParticipantRemoved ParticipantRemoved;
+		WINPR_ATTR_NODISCARD psEncomspChangeParticipantControlLevel ChangeParticipantControlLevel;
+		WINPR_ATTR_NODISCARD psEncomspGraphicsStreamPaused GraphicsStreamPaused;
+		WINPR_ATTR_NODISCARD psEncomspGraphicsStreamResumed GraphicsStreamResumed;

 		EncomspServerPrivate* priv;

--- a/include/freerdp/server/gfxredir.h
+++ b/include/freerdp/server/gfxredir.h
@@ -67,24 +67,26 @@ extern "C"
 		void* custom;
 		HANDLE vcm;

-		psGfxRedirOpen Open;
-		psGfxRedirClose Close;
+		WINPR_ATTR_NODISCARD psGfxRedirOpen Open;
+		WINPR_ATTR_NODISCARD psGfxRedirClose Close;

-		psGfxRedirError Error;
+		WINPR_ATTR_NODISCARD psGfxRedirError Error;

-		psGfxRedirGraphicsRedirectionLegacyCaps GraphicsRedirectionLegacyCaps;
+		WINPR_ATTR_NODISCARD psGfxRedirGraphicsRedirectionLegacyCaps GraphicsRedirectionLegacyCaps;

-		psGfxRedirGraphicsRedirectionCapsAdvertise GraphicsRedirectionCapsAdvertise;
-		psGfxRedirGraphicsRedirectionCapsConfirm GraphicsRedirectionCapsConfirm;
+		WINPR_ATTR_NODISCARD psGfxRedirGraphicsRedirectionCapsAdvertise
+		    GraphicsRedirectionCapsAdvertise;
+		WINPR_ATTR_NODISCARD psGfxRedirGraphicsRedirectionCapsConfirm
+		    GraphicsRedirectionCapsConfirm;

-		psGfxRedirOpenPool OpenPool;
-		psGfxRedirClosePool ClosePool;
+		WINPR_ATTR_NODISCARD psGfxRedirOpenPool OpenPool;
+		WINPR_ATTR_NODISCARD psGfxRedirClosePool ClosePool;

-		psGfxRedirCreateBuffer CreateBuffer;
-		psGfxRedirDestroyBuffer DestroyBuffer;
+		WINPR_ATTR_NODISCARD psGfxRedirCreateBuffer CreateBuffer;
+		WINPR_ATTR_NODISCARD psGfxRedirDestroyBuffer DestroyBuffer;

-		psGfxRedirPresentBuffer PresentBuffer;
-		psGfxRedirPresentBufferAck PresentBufferAck;
+		WINPR_ATTR_NODISCARD psGfxRedirPresentBuffer PresentBuffer;
+		WINPR_ATTR_NODISCARD psGfxRedirPresentBufferAck PresentBufferAck;

 		GfxRedirServerPrivate* priv;
 		rdpContext* rdpcontext;
--- a/include/freerdp/server/location.h
+++ b/include/freerdp/server/location.h
@@ -68,64 +68,64 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psLocationServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psLocationServerInitialize Initialize;

 		/**
 		 * Open the location channel.
 		 */
-		psLocationServerOpen Open;
+		WINPR_ATTR_NODISCARD psLocationServerOpen Open;

 		/**
 		 * Close the location channel.
 		 */
-		psLocationServerClose Close;
+		WINPR_ATTR_NODISCARD psLocationServerClose Close;

 		/**
 		 * Poll
 		 * When externalThread=TRUE, call Poll() periodically from your main loop.
 		 * If externalThread=FALSE do not call.
 		 */
-		psLocationServerPoll Poll;
+		WINPR_ATTR_NODISCARD psLocationServerPoll Poll;

 		/**
 		 * Retrieve the channel handle for use in conjunction with Poll().
 		 * If externalThread=FALSE do not call.
 		 */
-		psLocationServerChannelHandle ChannelHandle;
+		WINPR_ATTR_NODISCARD psLocationServerChannelHandle ChannelHandle;

 		/* All PDUs sent by the server don't require the header to be set */

 		/*
 		 * Send a ServerReady PDU.
 		 */
-		psLocationServerServerReady ServerReady;
+		WINPR_ATTR_NODISCARD psLocationServerServerReady ServerReady;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psLocationServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psLocationServerChannelIdAssigned ChannelIdAssigned;

 		/**
 		 * Callback for the ClientReady PDU.
 		 */
-		psLocationServerClientReady ClientReady;
+		WINPR_ATTR_NODISCARD psLocationServerClientReady ClientReady;

 		/**
 		 * Callback for the BaseLocation3D PDU.
 		 */
-		psLocationServerBaseLocation3D BaseLocation3D;
+		WINPR_ATTR_NODISCARD psLocationServerBaseLocation3D BaseLocation3D;

 		/**
 		 * Callback for the Location2DDelta PDU.
 		 */
-		psLocationServerLocation2DDelta Location2DDelta;
+		WINPR_ATTR_NODISCARD psLocationServerLocation2DDelta Location2DDelta;

 		/**
 		 * Callback for the Location3DDelta PDU.
 		 */
-		psLocationServerLocation3DDelta Location3DDelta;
+		WINPR_ATTR_NODISCARD psLocationServerLocation3DDelta Location3DDelta;

 		rdpContext* rdpcontext;
 	};
--- a/include/freerdp/server/proxy/proxy_context.h
+++ b/include/freerdp/server/proxy/proxy_context.h
@@ -63,8 +63,8 @@ extern "C"
 		UINT32 front_channel_id;
 		UINT32 back_channel_id;
 		pf_utils_channel_mode channelMode;
-		proxyChannelDataFn onFrontData;
-		proxyChannelDataFn onBackData;
+		WINPR_ATTR_NODISCARD proxyChannelDataFn onFrontData;
+		WINPR_ATTR_NODISCARD proxyChannelDataFn onBackData;
 		proxyChannelContextDtor contextDtor;
 		void* context;
 	};
@@ -120,7 +120,8 @@ extern "C"

 		pReceiveChannelData client_receive_channel_data_original;
 		wQueue* cached_server_channel_data;
-		BOOL (*sendChannelData)(pClientContext* pc, const proxyChannelDataEventInfo* ev);
+		WINPR_ATTR_NODISCARD BOOL (*sendChannelData)(pClientContext* pc,
+		                                             const proxyChannelDataEventInfo* ev);

 		/* X509 specific */
 		char* remote_hostname;
--- a/include/freerdp/server/proxy/proxy_modules_api.h
+++ b/include/freerdp/server/proxy/proxy_modules_api.h
@@ -65,52 +65,54 @@ extern "C"

 		UINT64 reserved1[32 - 2]; /* 2-32 */

-		BOOL (*PluginUnload)(proxyPlugin* plugin); /* 33 */
+		WINPR_ATTR_NODISCARD BOOL (*PluginUnload)(proxyPlugin* plugin); /* 33 */
 		UINT64 reserved2[66 - 34];                 /* 34 - 65 */

 		/* proxy hooks. a module can set these function pointers to register hooks */
-		proxyHookFn ClientInitConnect;     /* 66 custom=rdpContext* */
-		proxyHookFn ClientUninitConnect;   /* 67 custom=rdpContext* */
-		proxyHookFn ClientPreConnect;      /* 68 custom=rdpContext* */
-		proxyHookFn ClientPostConnect;     /* 69 custom=rdpContext* */
-		proxyHookFn ClientPostDisconnect;  /* 70 custom=rdpContext* */
-		proxyHookFn ClientX509Certificate; /* 71 custom=rdpContext* */
-		proxyHookFn ClientLoginFailure;    /* 72 custom=rdpContext* */
-		proxyHookFn ClientEndPaint;        /* 73 custom=rdpContext* */
-		proxyHookFn ClientRedirect;        /* 74 custom=rdpContext* */
-		proxyHookFn ClientLoadChannels;    /* 75 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientInitConnect;     /* 66 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientUninitConnect;   /* 67 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientPreConnect;      /* 68 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientPostConnect;     /* 69 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientPostDisconnect;  /* 70 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientX509Certificate; /* 71 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientLoginFailure;    /* 72 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientEndPaint;        /* 73 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientRedirect;        /* 74 custom=rdpContext* */
+		WINPR_ATTR_NODISCARD proxyHookFn ClientLoadChannels;    /* 75 custom=rdpContext* */
 		UINT64 reserved3[96 - 76];         /* 76-95 */

-		proxyHookFn ServerPostConnect;       /* 96  custom=freerdp_peer* */
-		proxyHookFn ServerPeerActivate;      /* 97  custom=freerdp_peer* */
-		proxyHookFn ServerChannelsInit;      /* 98  custom=freerdp_peer* */
-		proxyHookFn ServerChannelsFree;      /* 99  custom=freerdp_peer* */
-		proxyHookFn ServerSessionEnd;        /* 100 custom=freerdp_peer* */
-		proxyHookFn ServerSessionInitialize; /* 101 custom=freerdp_peer* */
-		proxyHookFn ServerSessionStarted;    /* 102 custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerPostConnect;       /* 96  custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerPeerActivate;      /* 97  custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerChannelsInit;      /* 98  custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerChannelsFree;      /* 99  custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerSessionEnd;        /* 100 custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerSessionInitialize; /* 101 custom=freerdp_peer* */
+		WINPR_ATTR_NODISCARD proxyHookFn ServerSessionStarted;    /* 102 custom=freerdp_peer* */

 		UINT64 reserved4[128 - 103]; /* 103 - 127 */

 		/* proxy filters. a module can set these function pointers to register filters */
-		proxyFilterFn KeyboardEvent;         /* 128 */
-		proxyFilterFn MouseEvent;            /* 129 */
-		proxyFilterFn ClientChannelData;     /* 130 passthrough channels data */
-		proxyFilterFn ServerChannelData;     /* 131 passthrough channels data */
-		proxyFilterFn DynamicChannelCreate;  /* 132 passthrough drdynvc channel create data */
-		proxyFilterFn ServerFetchTargetAddr; /* 133 */
-		proxyFilterFn ServerPeerLogon;       /* 134 */
-		proxyFilterFn ChannelCreate;         /* 135 passthrough drdynvc channel create data */
-		proxyFilterFn UnicodeEvent;          /* 136 */
-		proxyFilterFn MouseExEvent;          /* 137 */
+		WINPR_ATTR_NODISCARD proxyFilterFn KeyboardEvent;     /* 128 */
+		WINPR_ATTR_NODISCARD proxyFilterFn MouseEvent;        /* 129 */
+		WINPR_ATTR_NODISCARD proxyFilterFn ClientChannelData; /* 130 passthrough channels data */
+		WINPR_ATTR_NODISCARD proxyFilterFn ServerChannelData; /* 131 passthrough channels data */
+		WINPR_ATTR_NODISCARD proxyFilterFn
+		    DynamicChannelCreate; /* 132 passthrough drdynvc channel create data */
+		WINPR_ATTR_NODISCARD proxyFilterFn ServerFetchTargetAddr; /* 133 */
+		WINPR_ATTR_NODISCARD proxyFilterFn ServerPeerLogon;       /* 134 */
+		WINPR_ATTR_NODISCARD proxyFilterFn
+		    ChannelCreate; /* 135 passthrough drdynvc channel create data */
+		WINPR_ATTR_NODISCARD proxyFilterFn UnicodeEvent; /* 136 */
+		WINPR_ATTR_NODISCARD proxyFilterFn MouseExEvent; /* 137 */

 		/* proxy dynamic channel filters:
 		 *
 		 * - a function that returns the list of channels to intercept
 		 * - a function to call with the data received
 		 */
-		proxyFilterFn DynChannelToIntercept;    /* 138 */
-		proxyFilterFn DynChannelIntercept;      /* 139 */
-		proxyFilterFn StaticChannelToIntercept; /* 140 */
+		WINPR_ATTR_NODISCARD proxyFilterFn DynChannelToIntercept;    /* 138 */
+		WINPR_ATTR_NODISCARD proxyFilterFn DynChannelIntercept;      /* 139 */
+		WINPR_ATTR_NODISCARD proxyFilterFn StaticChannelToIntercept; /* 140 */
 		UINT64 reserved5[160 - 141];            /* 141-159 */

 		/* Runtime data fields */
@@ -134,13 +136,16 @@ extern "C"
 	struct proxy_plugins_manager
 	{
 		/* 0 used for registering a fresh new proxy plugin. */
-		BOOL (*RegisterPlugin)(struct proxy_plugins_manager* mgr, const proxyPlugin* plugin);
+		WINPR_ATTR_NODISCARD BOOL (*RegisterPlugin)(struct proxy_plugins_manager* mgr,
+		                                            const proxyPlugin* plugin);

 		/* 1 used for setting plugin's per-session info. */
-		BOOL (*SetPluginData)(struct proxy_plugins_manager* mgr, const char*, proxyData*, void*);
+		WINPR_ATTR_NODISCARD BOOL (*SetPluginData)(struct proxy_plugins_manager* mgr, const char*,
+		                                           proxyData*, void*);

 		/* 2 used for getting plugin's per-session info. */
-		void* (*GetPluginData)(struct proxy_plugins_manager* mgr, const char*, proxyData*);
+		WINPR_ATTR_NODISCARD void* (*GetPluginData)(struct proxy_plugins_manager* mgr, const char*,
+		                                            proxyData*);

 		/* 3 used for aborting a session. */
 		void (*AbortConnect)(struct proxy_plugins_manager* mgr, proxyData*);
@@ -148,7 +153,8 @@ extern "C"
 		UINT64 reserved[128 - 4]; /* 4-127 reserved fields */
 	};

-	typedef BOOL (*proxyModuleEntryPoint)(proxyPluginsManager* plugins_manager, void* userdata);
+	typedef WINPR_ATTR_NODISCARD BOOL (*proxyModuleEntryPoint)(proxyPluginsManager* plugins_manager,
+	                                                           void* userdata);

 /* filter events parameters */
 #define WINPR_PACK_PUSH
--- a/include/freerdp/server/rail.h
+++ b/include/freerdp/server/rail.h
@@ -101,42 +101,42 @@ extern "C"
 		HANDLE vcm;
 		void* custom;

-		psRailStart Start;
+		WINPR_ATTR_NODISCARD psRailStart Start;
 		psRailStop Stop;

 		/* Callbacks from client */
-		psRailClientHandshake ClientHandshake;
-		psRailClientClientStatus ClientClientStatus;
-		psRailClientExec ClientExec;
-		psRailClientSysparam ClientSysparam;
-		psRailClientActivate ClientActivate;
-		psRailClientSysmenu ClientSysmenu;
-		psRailClientSyscommand ClientSyscommand;
-		psRailClientNotifyEvent ClientNotifyEvent;
-		psRailClientGetAppidReq ClientGetAppidReq;
-		psRailClientWindowMove ClientWindowMove;
-		psRailClientSnapArrange ClientSnapArrange;
-		psRailClientLangbarInfo ClientLangbarInfo;
-		psRailClientLanguageImeInfo ClientLanguageImeInfo;
-		psRailClientCompartmentInfo ClientCompartmentInfo;
-		psRailClientCloak ClientCloak;
-		psRailClientTextScale ClientTextScale;
-		psRailClientCaretBlinkRate ClientCaretBlinkRate;
+		WINPR_ATTR_NODISCARD psRailClientHandshake ClientHandshake;
+		WINPR_ATTR_NODISCARD psRailClientClientStatus ClientClientStatus;
+		WINPR_ATTR_NODISCARD psRailClientExec ClientExec;
+		WINPR_ATTR_NODISCARD psRailClientSysparam ClientSysparam;
+		WINPR_ATTR_NODISCARD psRailClientActivate ClientActivate;
+		WINPR_ATTR_NODISCARD psRailClientSysmenu ClientSysmenu;
+		WINPR_ATTR_NODISCARD psRailClientSyscommand ClientSyscommand;
+		WINPR_ATTR_NODISCARD psRailClientNotifyEvent ClientNotifyEvent;
+		WINPR_ATTR_NODISCARD psRailClientGetAppidReq ClientGetAppidReq;
+		WINPR_ATTR_NODISCARD psRailClientWindowMove ClientWindowMove;
+		WINPR_ATTR_NODISCARD psRailClientSnapArrange ClientSnapArrange;
+		WINPR_ATTR_NODISCARD psRailClientLangbarInfo ClientLangbarInfo;
+		WINPR_ATTR_NODISCARD psRailClientLanguageImeInfo ClientLanguageImeInfo;
+		WINPR_ATTR_NODISCARD psRailClientCompartmentInfo ClientCompartmentInfo;
+		WINPR_ATTR_NODISCARD psRailClientCloak ClientCloak;
+		WINPR_ATTR_NODISCARD psRailClientTextScale ClientTextScale;
+		WINPR_ATTR_NODISCARD psRailClientCaretBlinkRate ClientCaretBlinkRate;

 		/* Methods for sending server side messages */
-		psRailServerHandshake ServerHandshake;
-		psRailServerHandshakeEx ServerHandshakeEx;
-		psRailServerSysparam ServerSysparam;
-		psRailServerLocalMoveSize ServerLocalMoveSize;
-		psRailServerMinMaxInfo ServerMinMaxInfo;
-		psRailServerTaskbarInfo ServerTaskbarInfo;
-		psRailServerLangbarInfo ServerLangbarInfo;
-		psRailServerExecResult ServerExecResult;
-		psRailServerZOrderSync ServerZOrderSync;
-		psRailServerCloak ServerCloak;
-		psRailServerPowerDisplayRequest ServerPowerDisplayRequest;
-		psRailServerGetAppidResp ServerGetAppidResp;
-		psRailServerGetAppidRespEx ServerGetAppidRespEx;
+		WINPR_ATTR_NODISCARD psRailServerHandshake ServerHandshake;
+		WINPR_ATTR_NODISCARD psRailServerHandshakeEx ServerHandshakeEx;
+		WINPR_ATTR_NODISCARD psRailServerSysparam ServerSysparam;
+		WINPR_ATTR_NODISCARD psRailServerLocalMoveSize ServerLocalMoveSize;
+		WINPR_ATTR_NODISCARD psRailServerMinMaxInfo ServerMinMaxInfo;
+		WINPR_ATTR_NODISCARD psRailServerTaskbarInfo ServerTaskbarInfo;
+		WINPR_ATTR_NODISCARD psRailServerLangbarInfo ServerLangbarInfo;
+		WINPR_ATTR_NODISCARD psRailServerExecResult ServerExecResult;
+		WINPR_ATTR_NODISCARD psRailServerZOrderSync ServerZOrderSync;
+		WINPR_ATTR_NODISCARD psRailServerCloak ServerCloak;
+		WINPR_ATTR_NODISCARD psRailServerPowerDisplayRequest ServerPowerDisplayRequest;
+		WINPR_ATTR_NODISCARD psRailServerGetAppidResp ServerGetAppidResp;
+		WINPR_ATTR_NODISCARD psRailServerGetAppidRespEx ServerGetAppidRespEx;

 		RailServerPrivate* priv;
 		rdpContext* rdpcontext;
--- a/include/freerdp/server/rdpdr.h
+++ b/include/freerdp/server/rdpdr.h
@@ -72,40 +72,40 @@ typedef UINT (*psRdpdrStart)(RdpdrServerContext* context);
 typedef UINT (*psRdpdrStop)(RdpdrServerContext* context);

 typedef UINT (*psRdpdrCapablityPDU)(RdpdrServerContext* context,
-                                    const RDPDR_CAPABILITY_HEADER* header, size_t size,
-                                    const BYTE* data);
+	                                const RDPDR_CAPABILITY_HEADER* header, size_t size,
+	                                const BYTE* data);
 typedef UINT (*psRdpdrReceivePDU)(RdpdrServerContext* context, const RDPDR_HEADER* header,
-                                  UINT error);
+	                              UINT error);
 typedef UINT (*psRdpdrReceiveAnnounceResponse)(RdpdrServerContext* context, UINT16 VersionMajor,
-                                               UINT16 VersionMinor, UINT32 ClientId);
+	                                           UINT16 VersionMinor, UINT32 ClientId);
 typedef UINT (*psRdpdrSendServerAnnounce)(RdpdrServerContext* context);
 typedef UINT (*psRdpdrReceiveDeviceAnnounce)(RdpdrServerContext* context,
-                                             const RdpdrDevice* device);
+	                                         const RdpdrDevice* device);
 typedef UINT (*psRdpdrReceiveDeviceRemove)(RdpdrServerContext* context, UINT32 deviceId,
-                                           const RdpdrDevice* device);
+	                                       const RdpdrDevice* device);
 typedef UINT (*psRdpdrReceiveClientNameRequest)(RdpdrServerContext* context, size_t ComputerNameLen,
-                                                const char* name);
+	                                            const char* name);

 typedef UINT (*psRdpdrDriveCreateDirectory)(RdpdrServerContext* context, void* callbackData,
-                                            UINT32 deviceId, const char* path);
+	                                        UINT32 deviceId, const char* path);
 typedef UINT (*psRdpdrDriveDeleteDirectory)(RdpdrServerContext* context, void* callbackData,
-                                            UINT32 deviceId, const char* path);
+	                                        UINT32 deviceId, const char* path);
 typedef UINT (*psRdpdrDriveQueryDirectory)(RdpdrServerContext* context, void* callbackData,
-                                           UINT32 deviceId, const char* path);
+	                                       UINT32 deviceId, const char* path);
 typedef UINT (*psRdpdrDriveOpenFile)(RdpdrServerContext* context, void* callbackData,
-                                     UINT32 deviceId, const char* path, UINT32 desiredAccess,
-                                     UINT32 createDisposition);
+	                                 UINT32 deviceId, const char* path, UINT32 desiredAccess,
+	                                 UINT32 createDisposition);
 typedef UINT (*psRdpdrDriveReadFile)(RdpdrServerContext* context, void* callbackData,
-                                     UINT32 deviceId, UINT32 fileId, UINT32 length, UINT32 offset);
+	                                 UINT32 deviceId, UINT32 fileId, UINT32 length, UINT32 offset);
 typedef UINT (*psRdpdrDriveWriteFile)(RdpdrServerContext* context, void* callbackData,
-                                      UINT32 deviceId, UINT32 fileId, const char* buffer,
-                                      UINT32 length, UINT32 offset);
+	                                  UINT32 deviceId, UINT32 fileId, const char* buffer,
+	                                  UINT32 length, UINT32 offset);
 typedef UINT (*psRdpdrDriveCloseFile)(RdpdrServerContext* context, void* callbackData,
-                                      UINT32 deviceId, UINT32 fileId);
+	                                  UINT32 deviceId, UINT32 fileId);
 typedef UINT (*psRdpdrDriveDeleteFile)(RdpdrServerContext* context, void* callbackData,
-                                       UINT32 deviceId, const char* path);
+	                                   UINT32 deviceId, const char* path);
 typedef UINT (*psRdpdrDriveRenameFile)(RdpdrServerContext* context, void* callbackData,
-                                       UINT32 deviceId, const char* oldPath, const char* newPath);
+	                                   UINT32 deviceId, const char* oldPath, const char* newPath);

 typedef void (*psRdpdrOnDriveCreateDirectoryComplete)(RdpdrServerContext* context,
                                                      void* callbackData, UINT32 ioStatus);
@@ -134,7 +134,7 @@ struct s_rdpdr_server_context
 {
 	HANDLE vcm;

-	psRdpdrStart Start;
+	WINPR_ATTR_NODISCARD psRdpdrStart Start;
 	psRdpdrStop Stop;

 	RdpdrServerPrivate* priv;
@@ -152,37 +152,40 @@ struct s_rdpdr_server_context
 	UINT16 supported;

 	/*** RDPDR message intercept callbacks */
-	psRdpdrCapablityPDU ReceiveCaps; /**< Called for each received capability */
-	psRdpdrCapablityPDU SendCaps;    /**< Called for each capability to be sent */
-	psRdpdrReceivePDU ReceivePDU;    /**< Called after a RDPDR pdu was received and parsed */
-	psRdpdrSendServerAnnounce
-	    SendServerAnnounce; /**< Called before the server sends the announce message */
-	psRdpdrReceiveAnnounceResponse
-	    ReceiveAnnounceResponse; /**< Called after the client announce response is received */
-	psRdpdrReceiveClientNameRequest
-	    ReceiveClientNameRequest; /**< Called after a client name request is received */
-	psRdpdrReceiveDeviceAnnounce
-	    ReceiveDeviceAnnounce; /** < Called after a new device request was received but before the
-	                              device is added */
-	psRdpdrReceiveDeviceRemove ReceiveDeviceRemove; /**< Called after a new device request was
-	                                                   received, but before it is removed */
+	WINPR_ATTR_NODISCARD psRdpdrCapablityPDU
+		ReceiveCaps;                                   /**< Called for each received capability */
+	WINPR_ATTR_NODISCARD psRdpdrCapablityPDU SendCaps; /**< Called for each capability to be sent */
+	WINPR_ATTR_NODISCARD psRdpdrReceivePDU
+		ReceivePDU; /**< Called after a RDPDR pdu was received and parsed */
+	WINPR_ATTR_NODISCARD psRdpdrSendServerAnnounce
+		SendServerAnnounce; /**< Called before the server sends the announce message */
+	WINPR_ATTR_NODISCARD psRdpdrReceiveAnnounceResponse
+		ReceiveAnnounceResponse; /**< Called after the client announce response is received */
+	WINPR_ATTR_NODISCARD psRdpdrReceiveClientNameRequest
+		ReceiveClientNameRequest; /**< Called after a client name request is received */
+	WINPR_ATTR_NODISCARD psRdpdrReceiveDeviceAnnounce
+		ReceiveDeviceAnnounce; /** < Called after a new device request was received but before the
+		                          device is added */
+	WINPR_ATTR_NODISCARD psRdpdrReceiveDeviceRemove
+		ReceiveDeviceRemove; /**< Called after a new device request was
+		   received, but before it is removed */

 	/*** Drive APIs called by the server. ***/
-	psRdpdrDriveCreateDirectory DriveCreateDirectory;
-	psRdpdrDriveDeleteDirectory DriveDeleteDirectory;
-	psRdpdrDriveQueryDirectory DriveQueryDirectory;
-	psRdpdrDriveOpenFile DriveOpenFile;
-	psRdpdrDriveReadFile DriveReadFile;
-	psRdpdrDriveWriteFile DriveWriteFile;
-	psRdpdrDriveCloseFile DriveCloseFile;
-	psRdpdrDriveDeleteFile DriveDeleteFile;
-	psRdpdrDriveRenameFile DriveRenameFile;
+	WINPR_ATTR_NODISCARD psRdpdrDriveCreateDirectory DriveCreateDirectory;
+	WINPR_ATTR_NODISCARD psRdpdrDriveDeleteDirectory DriveDeleteDirectory;
+	WINPR_ATTR_NODISCARD psRdpdrDriveQueryDirectory DriveQueryDirectory;
+	WINPR_ATTR_NODISCARD psRdpdrDriveOpenFile DriveOpenFile;
+	WINPR_ATTR_NODISCARD psRdpdrDriveReadFile DriveReadFile;
+	WINPR_ATTR_NODISCARD psRdpdrDriveWriteFile DriveWriteFile;
+	WINPR_ATTR_NODISCARD psRdpdrDriveCloseFile DriveCloseFile;
+	WINPR_ATTR_NODISCARD psRdpdrDriveDeleteFile DriveDeleteFile;
+	WINPR_ATTR_NODISCARD psRdpdrDriveRenameFile DriveRenameFile;

 	/*** Drive callbacks registered by the server. ***/
-	psRdpdrOnDeviceCreate OnDriveCreate; /**< Called for devices of type \b RDPDR_DTYP_FILESYSTEM
-	                                        after \b ReceiveDeviceAnnounce */
-	psRdpdrOnDeviceDelete OnDriveDelete; /**< Called for devices of type \b RDPDR_DTYP_FILESYSTEM
-	                                        after \b ReceiveDeviceRemove */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceCreate OnDriveCreate; /**< Called for devices of type \b
+		                                    RDPDR_DTYP_FILESYSTEM after \b ReceiveDeviceAnnounce */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceDelete OnDriveDelete; /**< Called for devices of type \b
+		                                    RDPDR_DTYP_FILESYSTEM after \b ReceiveDeviceRemove */
 	psRdpdrOnDriveCreateDirectoryComplete OnDriveCreateDirectoryComplete;
 	psRdpdrOnDriveDeleteDirectoryComplete OnDriveDeleteDirectoryComplete;
 	psRdpdrOnDriveQueryDirectoryComplete OnDriveQueryDirectoryComplete;
@@ -194,28 +197,29 @@ struct s_rdpdr_server_context
 	psRdpdrOnDriveRenameFileComplete OnDriveRenameFileComplete;

 	/*** Serial Port callbacks registered by the server. ***/
-	psRdpdrOnDeviceCreate OnSerialPortCreate; /**< Called for devices of type \b RDPDR_DTYP_SERIAL
-	                                       after \b ReceiveDeviceAnnounce */
-	psRdpdrOnDeviceDelete OnSerialPortDelete; /**< Called for devices of type \b RDPDR_DTYP_SERIAL
-	                                       after \b ReceiveDeviceRemove */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceCreate OnSerialPortCreate; /**< Called for devices of type
+		                                   \b RDPDR_DTYP_SERIAL after \b ReceiveDeviceAnnounce */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceDelete OnSerialPortDelete; /**< Called for devices of type
+		                                   \b RDPDR_DTYP_SERIAL after \b ReceiveDeviceRemove */

 	/*** Parallel Port callbacks registered by the server. ***/
-	psRdpdrOnDeviceCreate OnParallelPortCreate; /**< Called for devices of type \b
-	                                       RDPDR_DTYP_PARALLEL after \b ReceiveDeviceAnnounce */
-	psRdpdrOnDeviceDelete OnParallelPortDelete; /**< Called for devices of type \b
-	                                       RDPDR_DTYP_PARALLEL after \b ReceiveDeviceRemove */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceCreate OnParallelPortCreate; /**< Called for devices of type
+		                                   \b RDPDR_DTYP_PARALLEL after \b ReceiveDeviceAnnounce */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceDelete OnParallelPortDelete; /**< Called for devices of type
+		                                   \b RDPDR_DTYP_PARALLEL after \b ReceiveDeviceRemove */

 	/*** Printer callbacks registered by the server. ***/
-	psRdpdrOnDeviceCreate OnPrinterCreate; /**< Called for devices of type RDPDR_DTYP_PRINT after \b
-	                                          ReceiveDeviceAnnounce */
-	psRdpdrOnDeviceDelete OnPrinterDelete; /**< Called for devices of type RDPDR_DTYP_PRINT after \b
-	                                          ReceiveDeviceRemove */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceCreate OnPrinterCreate; /**< Called for devices of type
+		                                      RDPDR_DTYP_PRINT after \b ReceiveDeviceAnnounce */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceDelete OnPrinterDelete; /**< Called for devices of type
+		                                      RDPDR_DTYP_PRINT after \b ReceiveDeviceRemove */

 	/*** Smartcard callbacks registered by the server. ***/
-	psRdpdrOnDeviceCreate OnSmartcardCreate; /**< Called for devices of type RDPDR_DTYP_SMARTCARD
-	                                            after                    \b ReceiveDeviceAnnounce */
-	psRdpdrOnDeviceDelete OnSmartcardDelete; /**< Called for devices of type RDPDR_DTYP_SMARTCARD
-	                                            after \b                ReceiveDeviceRemove */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceCreate
+		OnSmartcardCreate; /**< Called for devices of type RDPDR_DTYP_SMARTCARD
+		 after                    \b ReceiveDeviceAnnounce */
+	WINPR_ATTR_NODISCARD psRdpdrOnDeviceDelete OnSmartcardDelete; /**< Called for devices of type
+		                                        RDPDR_DTYP_SMARTCARD after \b ReceiveDeviceRemove */

 	rdpContext* rdpcontext;
 };
--- a/include/freerdp/server/rdpecam-enumerator.h
+++ b/include/freerdp/server/rdpecam-enumerator.h
@@ -70,57 +70,59 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psCamDevEnumServerServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerInitialize Initialize;

 		/**
 		 * Open the camera device enumerator channel.
 		 */
-		psCamDevEnumServerServerOpen Open;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerOpen Open;

 		/**
 		 * Close the camera device enumerator channel.
 		 */
-		psCamDevEnumServerServerClose Close;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerClose Close;

 		/**
 		 * Poll
 		 * When externalThread=TRUE, call Poll() periodically from your main loop.
 		 * If externalThread=FALSE do not call.
 		 */
-		psCamDevEnumServerServerPoll Poll;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerPoll Poll;

 		/**
 		 * Retrieve the channel handle for use in conjunction with Poll().
 		 * If externalThread=FALSE do not call.
 		 */
-		psCamDevEnumServerServerChannelHandle ChannelHandle;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerChannelHandle ChannelHandle;

 		/*
 		 * Send a Select Version Response PDU.
 		 */
-		psCamDevEnumServerServerSelectVersionResponse SelectVersionResponse;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerSelectVersionResponse SelectVersionResponse;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psCamDevEnumServerServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerChannelIdAssigned ChannelIdAssigned;

 		/**
 		 * Callback for the Select Version Request PDU.
 		 */
-		psCamDevEnumServerServerSelectVersionRequest SelectVersionRequest;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerSelectVersionRequest SelectVersionRequest;

 		/**
 		 * Callback for the Device Added Notification PDU.
 		 */
-		psCamDevEnumServerServerDeviceAddedNotification DeviceAddedNotification;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerDeviceAddedNotification
+		    DeviceAddedNotification;

 		/**
 		 * Callback for the Device Removed Notification PDU.
 		 */
-		psCamDevEnumServerServerDeviceRemovedNotification DeviceRemovedNotification;
+		WINPR_ATTR_NODISCARD psCamDevEnumServerServerDeviceRemovedNotification
+		    DeviceRemovedNotification;

 		rdpContext* rdpcontext;
 	};
--- a/include/freerdp/server/rdpecam.h
+++ b/include/freerdp/server/rdpecam.h
@@ -132,30 +132,30 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psCameraDeviceServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerInitialize Initialize;

 		/**
 		 * Open the camera device channel.
 		 */
-		psCameraDeviceServerOpen Open;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerOpen Open;

 		/**
 		 * Close the camera device channel.
 		 */
-		psCameraDeviceServerClose Close;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerClose Close;

 		/**
 		 * Poll
 		 * When externalThread=TRUE, call Poll() periodically from your main loop.
 		 * If externalThread=FALSE do not call.
 		 */
-		psCameraDeviceServerPoll Poll;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerPoll Poll;

 		/**
 		 * Retrieve the channel handle for use in conjunction with Poll().
 		 * If externalThread=FALSE do not call.
 		 */
-		psCameraDeviceServerChannelHandle ChannelHandle;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerChannelHandle ChannelHandle;

 		/**
 		 * For the following server to client PDUs,
@@ -165,109 +165,109 @@ extern "C"
 		/**
 		 * Send a Activate Device Request PDU.
 		 */
-		psCameraDeviceServerActivateDeviceRequest ActivateDeviceRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerActivateDeviceRequest ActivateDeviceRequest;

 		/**
 		 * Send a Deactivate Device Request PDU.
 		 */
-		psCameraDeviceServerDeactivateDeviceRequest DeactivateDeviceRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerDeactivateDeviceRequest DeactivateDeviceRequest;

 		/**
 		 * Send a Stream List Request PDU.
 		 */
-		psCameraDeviceServerStreamListRequest StreamListRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerStreamListRequest StreamListRequest;

 		/**
 		 * Send a Media Type List Request PDU.
 		 */
-		psCameraDeviceServerMediaTypeListRequest MediaTypeListRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerMediaTypeListRequest MediaTypeListRequest;

 		/**
 		 * Send a Current Media Type Request PDU.
 		 */
-		psCameraDeviceServerCurrentMediaTypeRequest CurrentMediaTypeRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerCurrentMediaTypeRequest CurrentMediaTypeRequest;

 		/**
 		 * Send a Start Streams Request PDU.
 		 */
-		psCameraDeviceServerStartStreamsRequest StartStreamsRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerStartStreamsRequest StartStreamsRequest;

 		/**
 		 * Send a Stop Streams Request PDU.
 		 */
-		psCameraDeviceServerStopStreamsRequest StopStreamsRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerStopStreamsRequest StopStreamsRequest;

 		/**
 		 * Send a Sample Request PDU.
 		 */
-		psCameraDeviceServerSampleRequest SampleRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerSampleRequest SampleRequest;

 		/**
 		 * Send a Property List Request PDU.
 		 */
-		psCameraDeviceServerPropertyListRequest PropertyListRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerPropertyListRequest PropertyListRequest;

 		/**
 		 * Send a Property Value Request PDU.
 		 */
-		psCameraDeviceServerPropertyValueRequest PropertyValueRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerPropertyValueRequest PropertyValueRequest;

 		/**
 		 * Send a Set Property Value Request PDU.
 		 */
-		psCameraDeviceServerSetPropertyValueRequest SetPropertyValueRequest;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerSetPropertyValueRequest SetPropertyValueRequest;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psCameraDeviceServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerChannelIdAssigned ChannelIdAssigned;

 		/**
 		 * Callback for the Success Response PDU.
 		 */
-		psCameraDeviceServerSuccessResponse SuccessResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerSuccessResponse SuccessResponse;

 		/**
 		 * Callback for the Error Response PDU.
 		 */
-		psCameraDeviceServerErrorResponse ErrorResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerErrorResponse ErrorResponse;

 		/**
 		 * Callback for the Stream List Response PDU.
 		 */
-		psCameraDeviceServerStreamListResponse StreamListResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerStreamListResponse StreamListResponse;

 		/**
 		 * Callback for the Media Type List Response PDU.
 		 */
-		psCameraDeviceServerMediaTypeListResponse MediaTypeListResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerMediaTypeListResponse MediaTypeListResponse;

 		/**
 		 * Callback for the Current Media Type Response PDU.
 		 */
-		psCameraDeviceServerCurrentMediaTypeResponse CurrentMediaTypeResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerCurrentMediaTypeResponse CurrentMediaTypeResponse;

 		/**
 		 * Callback for the Sample Response PDU.
 		 */
-		psCameraDeviceServerSampleResponse SampleResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerSampleResponse SampleResponse;

 		/**
 		 * Callback for the Sample Error Response PDU.
 		 */
-		psCameraDeviceServerSampleErrorResponse SampleErrorResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerSampleErrorResponse SampleErrorResponse;

 		/**
 		 * Callback for the Property List Response PDU.
 		 */
-		psCameraDeviceServerPropertyListResponse PropertyListResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerPropertyListResponse PropertyListResponse;

 		/**
 		 * Callback for the Property Value Response PDU.
 		 */
-		psCameraDeviceServerPropertyValueResponse PropertyValueResponse;
+		WINPR_ATTR_NODISCARD psCameraDeviceServerPropertyValueResponse PropertyValueResponse;

 		rdpContext* rdpcontext;
 	};
--- a/include/freerdp/server/rdpei.h
+++ b/include/freerdp/server/rdpei.h
@@ -48,17 +48,20 @@ extern "C"
 		UINT32 protocolFlags;

 		/** callbacks that can be set by the user */
-		UINT (*onClientReady)(RdpeiServerContext* context);
-		UINT (*onTouchEvent)(RdpeiServerContext* context, const RDPINPUT_TOUCH_EVENT* touchEvent);
-		UINT (*onPenEvent)(RdpeiServerContext* context, const RDPINPUT_PEN_EVENT* penEvent);
-		UINT (*onTouchReleased)(RdpeiServerContext* context, BYTE contactId);
+		WINPR_ATTR_NODISCARD UINT (*onClientReady)(RdpeiServerContext* context);
+		WINPR_ATTR_NODISCARD UINT (*onTouchEvent)(RdpeiServerContext* context,
+		                                          const RDPINPUT_TOUCH_EVENT* touchEvent);
+		WINPR_ATTR_NODISCARD UINT (*onPenEvent)(RdpeiServerContext* context,
+		                                        const RDPINPUT_PEN_EVENT* penEvent);
+		WINPR_ATTR_NODISCARD UINT (*onTouchReleased)(RdpeiServerContext* context, BYTE contactId);

 		void* user_data; /* user data, useful for callbacks */

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		BOOL (*onChannelIdAssigned)(RdpeiServerContext* context, UINT32 channelId);
+		WINPR_ATTR_NODISCARD BOOL (*onChannelIdAssigned)(RdpeiServerContext* context,
+		                                                 UINT32 channelId);

 		/*** APIs called by the server. ***/

@@ -66,13 +69,13 @@ extern "C"
 		 * Open the input channel.
 		 * @since version 3.15.0
 		 */
-		psRdpeiServerOpen Open;
+		WINPR_ATTR_NODISCARD psRdpeiServerOpen Open;

 		/**
 		 * Close the input channel.
 		 * @since version 3.15.0
 		 */
-		psRdpeiServerClose Close;
+		WINPR_ATTR_NODISCARD psRdpeiServerClose Close;
 	};

 	FREERDP_API void rdpei_server_context_free(RdpeiServerContext* context);
--- a/include/freerdp/server/rdpemsc.h
+++ b/include/freerdp/server/rdpemsc.h
@@ -68,54 +68,54 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psMouseCursorServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psMouseCursorServerInitialize Initialize;

 		/**
 		 * Open the mouse cursor channel.
 		 */
-		psMouseCursorServerOpen Open;
+		WINPR_ATTR_NODISCARD psMouseCursorServerOpen Open;

 		/**
 		 * Close the mouse cursor channel.
 		 */
-		psMouseCursorServerClose Close;
+		WINPR_ATTR_NODISCARD psMouseCursorServerClose Close;

 		/**
 		 * Poll
 		 * When externalThread=TRUE, call Poll() periodically from your main loop.
 		 * If externalThread=FALSE do not call.
 		 */
-		psMouseCursorServerPoll Poll;
+		WINPR_ATTR_NODISCARD psMouseCursorServerPoll Poll;

 		/**
 		 * Retrieve the channel handle for use in conjunction with Poll().
 		 * If externalThread=FALSE do not call.
 		 */
-		psMouseCursorServerChannelHandle ChannelHandle;
+		WINPR_ATTR_NODISCARD psMouseCursorServerChannelHandle ChannelHandle;

 		/* All PDUs sent by the server don't require the pduType to be set */

 		/*
 		 * Send a CapsConfirm PDU.
 		 */
-		psMouseCursorServerCapsConfirm CapsConfirm;
+		WINPR_ATTR_NODISCARD psMouseCursorServerCapsConfirm CapsConfirm;

 		/*
 		 * Send a MouseptrUpdate PDU.
 		 */
-		psMouseCursorServerMouseptrUpdate MouseptrUpdate;
+		WINPR_ATTR_NODISCARD psMouseCursorServerMouseptrUpdate MouseptrUpdate;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psMouseCursorServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psMouseCursorServerChannelIdAssigned ChannelIdAssigned;

 		/**
 		 * Callback for the CapsAdvertise PDU.
 		 */
-		psMouseCursorServerCapsAdvertise CapsAdvertise;
+		WINPR_ATTR_NODISCARD psMouseCursorServerCapsAdvertise CapsAdvertise;

 		rdpContext* rdpcontext;
 	};
--- a/include/freerdp/server/rdpgfx.h
+++ b/include/freerdp/server/rdpgfx.h
@@ -95,32 +95,32 @@ extern "C"
 		HANDLE vcm;
 		void* custom;

-		psRdpgfxServerOpen Open;
-		psRdpgfxServerClose Close;
+		WINPR_ATTR_NODISCARD psRdpgfxServerOpen Open;
+		WINPR_ATTR_NODISCARD psRdpgfxServerClose Close;

-		psRdpgfxResetGraphics ResetGraphics;
-		psRdpgfxStartFrame StartFrame;
-		psRdpgfxEndFrame EndFrame;
-		psRdpgfxSurfaceCommand SurfaceCommand;
-		psRdpgfxSurfaceFrameCommand SurfaceFrameCommand;
-		psRdpgfxDeleteEncodingContext DeleteEncodingContext;
-		psRdpgfxCreateSurface CreateSurface;
-		psRdpgfxDeleteSurface DeleteSurface;
-		psRdpgfxSolidFill SolidFill;
-		psRdpgfxSurfaceToSurface SurfaceToSurface;
-		psRdpgfxSurfaceToCache SurfaceToCache;
-		psRdpgfxCacheToSurface CacheToSurface;
-		psRdpgfxCacheImportOffer CacheImportOffer;
-		psRdpgfxCacheImportReply CacheImportReply;
-		psRdpgfxEvictCacheEntry EvictCacheEntry;
-		psRdpgfxMapSurfaceToOutput MapSurfaceToOutput;
-		psRdpgfxMapSurfaceToWindow MapSurfaceToWindow;
-		psRdpgfxMapSurfaceToScaledOutput MapSurfaceToScaledOutput;
-		psRdpgfxMapSurfaceToScaledWindow MapSurfaceToScaledWindow;
-		psRdpgfxCapsAdvertise CapsAdvertise;
-		psRdpgfxCapsConfirm CapsConfirm;
-		psRdpgfxFrameAcknowledge FrameAcknowledge;
-		psRdpgfxQoeFrameAcknowledge QoeFrameAcknowledge;
+		WINPR_ATTR_NODISCARD psRdpgfxResetGraphics ResetGraphics;
+		WINPR_ATTR_NODISCARD psRdpgfxStartFrame StartFrame;
+		WINPR_ATTR_NODISCARD psRdpgfxEndFrame EndFrame;
+		WINPR_ATTR_NODISCARD psRdpgfxSurfaceCommand SurfaceCommand;
+		WINPR_ATTR_NODISCARD psRdpgfxSurfaceFrameCommand SurfaceFrameCommand;
+		WINPR_ATTR_NODISCARD psRdpgfxDeleteEncodingContext DeleteEncodingContext;
+		WINPR_ATTR_NODISCARD psRdpgfxCreateSurface CreateSurface;
+		WINPR_ATTR_NODISCARD psRdpgfxDeleteSurface DeleteSurface;
+		WINPR_ATTR_NODISCARD psRdpgfxSolidFill SolidFill;
+		WINPR_ATTR_NODISCARD psRdpgfxSurfaceToSurface SurfaceToSurface;
+		WINPR_ATTR_NODISCARD psRdpgfxSurfaceToCache SurfaceToCache;
+		WINPR_ATTR_NODISCARD psRdpgfxCacheToSurface CacheToSurface;
+		WINPR_ATTR_NODISCARD psRdpgfxCacheImportOffer CacheImportOffer;
+		WINPR_ATTR_NODISCARD psRdpgfxCacheImportReply CacheImportReply;
+		WINPR_ATTR_NODISCARD psRdpgfxEvictCacheEntry EvictCacheEntry;
+		WINPR_ATTR_NODISCARD psRdpgfxMapSurfaceToOutput MapSurfaceToOutput;
+		WINPR_ATTR_NODISCARD psRdpgfxMapSurfaceToWindow MapSurfaceToWindow;
+		WINPR_ATTR_NODISCARD psRdpgfxMapSurfaceToScaledOutput MapSurfaceToScaledOutput;
+		WINPR_ATTR_NODISCARD psRdpgfxMapSurfaceToScaledWindow MapSurfaceToScaledWindow;
+		WINPR_ATTR_NODISCARD psRdpgfxCapsAdvertise CapsAdvertise;
+		WINPR_ATTR_NODISCARD psRdpgfxCapsConfirm CapsConfirm;
+		WINPR_ATTR_NODISCARD psRdpgfxFrameAcknowledge FrameAcknowledge;
+		WINPR_ATTR_NODISCARD psRdpgfxQoeFrameAcknowledge QoeFrameAcknowledge;

 		RdpgfxServerPrivate* priv;
 		rdpContext* rdpcontext;
@@ -128,7 +128,7 @@ extern "C"
 		/**
 		 * Callback, when the channel got its id assigned.
 		 */
-		psRdpgfxServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psRdpgfxServerChannelIdAssigned ChannelIdAssigned;
 		/**
 		 * Optional: Set thread handling.
 		 * When externalThread=TRUE, the application is responsible to call
@@ -136,7 +136,7 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psRdpgfxServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psRdpgfxServerInitialize Initialize;
 	};

 	FREERDP_API void rdpgfx_server_context_free(RdpgfxServerContext* context);
--- a/include/freerdp/server/rdpsnd.h
+++ b/include/freerdp/server/rdpsnd.h
@@ -64,7 +64,7 @@ extern "C"
 	{
 		HANDLE vcm;

-		psRdpsndStart Start;
+		WINPR_ATTR_NODISCARD psRdpsndStart Start;
 		psRdpsndStop Stop;

 		RdpsndServerPrivate* priv;
@@ -99,27 +99,27 @@ extern "C"
 		 * whether the initialization succeed. If not, the "Activated" callback
 		 * will not be called and the server must not call any API on this context.
 		 */
-		psRdpsndServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psRdpsndServerInitialize Initialize;

 		/**
 		 * Choose the audio format to be sent. The index argument is an index into
 		 * the client_formats array and must be smaller than num_client_formats.
 		 */
-		psRdpsndServerSelectFormat SelectFormat;
+		WINPR_ATTR_NODISCARD psRdpsndServerSelectFormat SelectFormat;
 		/**
 		 * Send audio samples. Actually bytes in the buffer must be:
 		 * nframes * src_format.nBitsPerSample * src_format.nChannels / 8
 		 */
-		psRdpsndServerSendSamples SendSamples;
+		WINPR_ATTR_NODISCARD psRdpsndServerSendSamples SendSamples;

 		/**
 		 * Called when block confirm is received from the client
 		 */
-		psRdpsndServerConfirmBlock ConfirmBlock;
+		WINPR_ATTR_NODISCARD psRdpsndServerConfirmBlock ConfirmBlock;
 		/**
 		 * Set the volume level of the client. Valid range is between 0 and 0xFFFF.
 		 */
-		psRdpsndServerSetVolume SetVolume;
+		WINPR_ATTR_NODISCARD psRdpsndServerSetVolume SetVolume;
 		/**
 		 * Close the audio stream.
 		 */
@@ -155,28 +155,28 @@ extern "C"
 		 * opening the channel.
 		 * Also used to restart the protocol after sending the Close PDU.
 		 */
-		psRdpsndServerSendFormats SendFormats;
+		WINPR_ATTR_NODISCARD psRdpsndServerSendFormats SendFormats;
 		/**
 		 * Send Training PDU.
 		 */
-		psRdpsndServerTraining Training;
+		WINPR_ATTR_NODISCARD psRdpsndServerTraining Training;

 		/**
 		 * Send encoded audio samples using a Wave2 PDU.
 		 * When successful, the block_no member is incremented.
 		 */
-		psRdpsndServerSendSamples2 SendSamples2;
+		WINPR_ATTR_NODISCARD psRdpsndServerSendSamples2 SendSamples2;

 		/**
 		 * Called when a TrainingConfirm PDU is received from the client.
 		 */
-		psRdpsndServerTrainingConfirm TrainingConfirm;
+		WINPR_ATTR_NODISCARD psRdpsndServerTrainingConfirm TrainingConfirm;

 		/**
 		 * Callback, when the channel got its id assigned.
 		 * Only called, when use_dynamic_virtual_channel=TRUE.
 		 */
-		psRdpsndChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psRdpsndChannelIdAssigned ChannelIdAssigned;

 		UINT16 udpPort;  /** @since version 3.14.0 */
 		UINT8 lastblock; /** @since version 3.14.0 */
--- a/include/freerdp/server/remdesk.h
+++ b/include/freerdp/server/remdesk.h
@@ -48,7 +48,7 @@ extern "C"
 		HANDLE vcm;
 		void* custom;

-		psRemdeskStart Start;
+		WINPR_ATTR_NODISCARD psRemdeskStart Start;
 		psRemdeskStop Stop;

 		RemdeskServerPrivate* priv;
--- a/include/freerdp/server/shadow.h
+++ b/include/freerdp/server/shadow.h
@@ -200,16 +200,16 @@ extern "C"

 	struct S_RDP_SHADOW_ENTRY_POINTS
 	{
-		pfnShadowSubsystemNew New;
+		WINPR_ATTR_NODISCARD pfnShadowSubsystemNew New;
 		pfnShadowSubsystemFree Free;

-		pfnShadowSubsystemInit Init;
+		WINPR_ATTR_NODISCARD pfnShadowSubsystemInit Init;
 		pfnShadowSubsystemUninit Uninit;

-		pfnShadowSubsystemStart Start;
+		WINPR_ATTR_NODISCARD pfnShadowSubsystemStart Start;
 		pfnShadowSubsystemStop Stop;

-		pfnShadowEnumMonitors EnumMonitors;
+		WINPR_ATTR_NODISCARD pfnShadowEnumMonitors EnumMonitors;
 	};

 	struct rdp_shadow_subsystem
@@ -236,21 +236,21 @@ extern "C"
 		AUDIO_FORMAT* audinFormats;
 		size_t nAudinFormats;

-		pfnShadowSynchronizeEvent SynchronizeEvent;
-		pfnShadowKeyboardEvent KeyboardEvent;
-		pfnShadowUnicodeKeyboardEvent UnicodeKeyboardEvent;
-		pfnShadowMouseEvent MouseEvent;
-		pfnShadowExtendedMouseEvent ExtendedMouseEvent;
-		pfnShadowChannelAudinServerReceiveSamples AudinServerReceiveSamples;
+		WINPR_ATTR_NODISCARD pfnShadowSynchronizeEvent SynchronizeEvent;
+		WINPR_ATTR_NODISCARD pfnShadowKeyboardEvent KeyboardEvent;
+		WINPR_ATTR_NODISCARD pfnShadowUnicodeKeyboardEvent UnicodeKeyboardEvent;
+		WINPR_ATTR_NODISCARD pfnShadowMouseEvent MouseEvent;
+		WINPR_ATTR_NODISCARD pfnShadowExtendedMouseEvent ExtendedMouseEvent;
+		WINPR_ATTR_NODISCARD pfnShadowChannelAudinServerReceiveSamples AudinServerReceiveSamples;

-		pfnShadowAuthenticate Authenticate;
-		pfnShadowClientConnect ClientConnect;
+		WINPR_ATTR_NODISCARD pfnShadowAuthenticate Authenticate;
+		WINPR_ATTR_NODISCARD pfnShadowClientConnect ClientConnect;
 		pfnShadowClientDisconnect ClientDisconnect;
-		pfnShadowClientCapabilities ClientCapabilities;
+		WINPR_ATTR_NODISCARD pfnShadowClientCapabilities ClientCapabilities;

 		rdpShadowServer* server;

-		pfnShadowRelMouseEvent RelMouseEvent; /** @since version 3.15.0 */
+		WINPR_ATTR_NODISCARD pfnShadowRelMouseEvent RelMouseEvent; /** @since version 3.15.0 */
 	};

 /* Definition of message between subsystem and clients */
--- a/include/freerdp/server/telemetry.h
+++ b/include/freerdp/server/telemetry.h
@@ -60,41 +60,41 @@ extern "C"
 		 *
 		 * Defaults to externalThread=FALSE
 		 */
-		psTelemetryServerInitialize Initialize;
+		WINPR_ATTR_NODISCARD psTelemetryServerInitialize Initialize;

 		/**
 		 * Open the telemetry channel.
 		 */
-		psTelemetryServerOpen Open;
+		WINPR_ATTR_NODISCARD psTelemetryServerOpen Open;

 		/**
 		 * Close the telemetry channel.
 		 */
-		psTelemetryServerClose Close;
+		WINPR_ATTR_NODISCARD psTelemetryServerClose Close;

 		/**
 		 * Poll
 		 * When externalThread=TRUE, call Poll() periodically from your main loop.
 		 * If externalThread=FALSE do not call.
 		 */
-		psTelemetryServerPoll Poll;
+		WINPR_ATTR_NODISCARD psTelemetryServerPoll Poll;

 		/**
 		 * Retrieve the channel handle for use in conjunction with Poll().
 		 * If externalThread=FALSE do not call.
 		 */
-		psTelemetryServerChannelHandle ChannelHandle;
+		WINPR_ATTR_NODISCARD psTelemetryServerChannelHandle ChannelHandle;

 		/*** Callbacks registered by the server. ***/

 		/**
 		 * Callback, when the channel got its id assigned
 		 */
-		psTelemetryServerChannelIdAssigned ChannelIdAssigned;
+		WINPR_ATTR_NODISCARD psTelemetryServerChannelIdAssigned ChannelIdAssigned;
 		/**
 		 * Callback for the RDP Telemetry PDU.
 		 */
-		psTelemetryServerRdpTelemetry RdpTelemetry;
+		WINPR_ATTR_NODISCARD psTelemetryServerRdpTelemetry RdpTelemetry;

 		rdpContext* rdpcontext;
 	};
--- a/include/freerdp/svc.h
+++ b/include/freerdp/svc.h
@@ -43,10 +43,10 @@ extern "C"
 	{
 		UINT32 cbSize;
 		UINT32 protocolVersion;
-		PVIRTUALCHANNELINIT pVirtualChannelInit;
-		PVIRTUALCHANNELOPEN pVirtualChannelOpen;
-		PVIRTUALCHANNELCLOSE pVirtualChannelClose;
-		PVIRTUALCHANNELWRITE pVirtualChannelWrite;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELINIT pVirtualChannelInit;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELOPEN pVirtualChannelOpen;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELCLOSE pVirtualChannelClose;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELWRITE pVirtualChannelWrite;

 		/* Extended Fields */
 		UINT32 MagicNumber;  /* identifies FreeRDP */
@@ -60,10 +60,10 @@ extern "C"
 	{
 		UINT32 cbSize;
 		UINT32 protocolVersion;
-		PVIRTUALCHANNELINITEX pVirtualChannelInitEx;
-		PVIRTUALCHANNELOPENEX pVirtualChannelOpenEx;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELINITEX pVirtualChannelInitEx;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELOPENEX pVirtualChannelOpenEx;
 		PVIRTUALCHANNELCLOSEEX pVirtualChannelCloseEx;
-		PVIRTUALCHANNELWRITEEX pVirtualChannelWriteEx;
+		WINPR_ATTR_NODISCARD PVIRTUALCHANNELWRITEEX pVirtualChannelWriteEx;

 		/* Extended Fields */
 		UINT32 MagicNumber;  /* identifies FreeRDP */
--- a/include/freerdp/transport_io.h
+++ b/include/freerdp/transport_io.h
@@ -68,11 +68,11 @@ extern "C"
 	typedef struct
 	{
 		ALIGN64 void* userContext;
-		ALIGN64 pTransportLayerRead Read;
-		ALIGN64 pTransportLayerWrite Write;
+		ALIGN64 WINPR_ATTR_NODISCARD pTransportLayerRead Read;
+		ALIGN64 WINPR_ATTR_NODISCARD pTransportLayerWrite Write;
 		ALIGN64 pTransportLayerFkt Close;
-		ALIGN64 pTransportLayerWait Wait;
-		ALIGN64 pTransportLayerGetEvent GetEvent;
+		ALIGN64 WINPR_ATTR_NODISCARD pTransportLayerWait Wait;
+		ALIGN64 WINPR_ATTR_NODISCARD pTransportLayerGetEvent GetEvent;
 		UINT64 reserved[64 - 6]; /* Reserve some space for ABI compatibility */
 	} rdpTransportLayer;

@@ -110,18 +110,18 @@ extern "C"

 	struct rdp_transport_io
 	{
-		pTCPConnect TCPConnect;
-		pTransportFkt TLSConnect;
-		pTransportFkt TLSAccept;
-		pTransportAttach TransportAttach;
-		pTransportFkt TransportDisconnect;
-		pTransportRWFkt ReadPdu;                   /* Reads a whole PDU from the transport */
-		pTransportRWFkt WritePdu;                  /* Writes a whole PDU to the transport */
-		pTransportRead ReadBytes;                  /* Reads up to a requested amount of bytes */
-		pTransportGetPublicKey GetPublicKey;       /** @since version 3.2.0 */
-		pTransportSetBlockingMode SetBlockingMode; /** @since version 3.3.0 */
-		pTransportConnectLayer ConnectLayer;       /** @since 3.9.0 */
-		pTransportAttachLayer AttachLayer;         /** @since 3.9.0 */
+		WINPR_ATTR_NODISCARD pTCPConnect TCPConnect;
+		WINPR_ATTR_NODISCARD pTransportFkt TLSConnect;
+		WINPR_ATTR_NODISCARD pTransportFkt TLSAccept;
+		WINPR_ATTR_NODISCARD pTransportAttach TransportAttach;
+		WINPR_ATTR_NODISCARD pTransportFkt TransportDisconnect;
+		WINPR_ATTR_NODISCARD pTransportRWFkt ReadPdu;  /* Reads a whole PDU from the transport */
+		WINPR_ATTR_NODISCARD pTransportRWFkt WritePdu; /* Writes a whole PDU to the transport */
+		WINPR_ATTR_NODISCARD pTransportRead ReadBytes; /* Reads up to a requested amount of bytes */
+		WINPR_ATTR_NODISCARD pTransportGetPublicKey GetPublicKey;       /** @since version 3.2.0 */
+		WINPR_ATTR_NODISCARD pTransportSetBlockingMode SetBlockingMode; /** @since version 3.3.0 */
+		WINPR_ATTR_NODISCARD pTransportConnectLayer ConnectLayer;       /** @since 3.9.0 */
+		WINPR_ATTR_NODISCARD pTransportAttachLayer AttachLayer;         /** @since 3.9.0 */
 		UINT64 reserved[64 - 12];                  /* Reserve some space for ABI compatibility */
 	};
 	typedef struct rdp_transport_io rdpTransportIo;
--- a/include/freerdp/update.h
+++ b/include/freerdp/update.h
@@ -202,16 +202,16 @@ extern "C"
 		rdpContext* context;     /* 0 */
 		UINT32 paddingA[16 - 1]; /* 1 */

-		pBeginPaint BeginPaint;                       /* 16 */
-		pEndPaint EndPaint;                           /* 17 */
-		pSetBounds SetBounds;                         /* 18 */
-		pSynchronize Synchronize;                     /* 19 */
-		pDesktopResize DesktopResize;                 /* 20 */
-		pBitmapUpdate BitmapUpdate;                   /* 21 */
-		pPalette Palette;                             /* 22 */
-		pPlaySound PlaySound;                         /* 23 */
-		pSetKeyboardIndicators SetKeyboardIndicators; /* 24 */
-		pSetKeyboardImeStatus SetKeyboardImeStatus;   /* 25 */
+		WINPR_ATTR_NODISCARD pBeginPaint BeginPaint;                       /* 16 */
+		WINPR_ATTR_NODISCARD pEndPaint EndPaint;                           /* 17 */
+		WINPR_ATTR_NODISCARD pSetBounds SetBounds;                         /* 18 */
+		WINPR_ATTR_NODISCARD pSynchronize Synchronize;                     /* 19 */
+		WINPR_ATTR_NODISCARD pDesktopResize DesktopResize;                 /* 20 */
+		WINPR_ATTR_NODISCARD pBitmapUpdate BitmapUpdate;                   /* 21 */
+		WINPR_ATTR_NODISCARD pPalette Palette;                             /* 22 */
+		WINPR_ATTR_NODISCARD pPlaySound PlaySound;                         /* 23 */
+		WINPR_ATTR_NODISCARD pSetKeyboardIndicators SetKeyboardIndicators; /* 24 */
+		WINPR_ATTR_NODISCARD pSetKeyboardImeStatus SetKeyboardImeStatus;   /* 25 */
 		UINT32 paddingB[32 - 26];                     /* 26 */

 		rdpPointerUpdate* pointer;     /* 32 */
@@ -226,13 +226,13 @@ extern "C"
 		pRemoteMonitors RemoteMonitors; /* 50 */
 		UINT32 paddingD[64 - 51];       /* 51 */

-		pSurfaceCommand SurfaceCommand;                   /* 64 */
-		pSurfaceBits SurfaceBits;                         /* 65 */
-		pSurfaceFrameMarker SurfaceFrameMarker;           /* 66 */
-		pSurfaceFrameBits SurfaceFrameBits;               /* 67 */
-		pSurfaceFrameAcknowledge SurfaceFrameAcknowledge; /* 68 */
-		pSaveSessionInfo SaveSessionInfo;                 /* 69 */
-		pServerStatusInfo ServerStatusInfo;               /* 70 */
+		WINPR_ATTR_NODISCARD pSurfaceCommand SurfaceCommand;                   /* 64 */
+		WINPR_ATTR_NODISCARD pSurfaceBits SurfaceBits;                         /* 65 */
+		WINPR_ATTR_NODISCARD pSurfaceFrameMarker SurfaceFrameMarker;           /* 66 */
+		WINPR_ATTR_NODISCARD pSurfaceFrameBits SurfaceFrameBits;               /* 67 */
+		WINPR_ATTR_NODISCARD pSurfaceFrameAcknowledge SurfaceFrameAcknowledge; /* 68 */
+		WINPR_ATTR_NODISCARD pSaveSessionInfo SaveSessionInfo;                 /* 69 */
+		WINPR_ATTR_NODISCARD pServerStatusInfo ServerStatusInfo;               /* 70 */
 		/* if autoCalculateBitmapData is set to TRUE, the server automatically
 		 * fills BITMAP_DATA struct members: flags, cbCompMainBodySize and cbCompFirstRowSize.
 		 */
--- a/include/freerdp/window.h
+++ b/include/freerdp/window.h
@@ -277,16 +277,16 @@ extern "C"
 		rdpContext* context;     /* 0 */
 		UINT32 paddingA[16 - 1]; /* 1 */

-		pWindowCreate WindowCreate;               /* 16 */
-		pWindowUpdate WindowUpdate;               /* 17 */
-		pWindowIcon WindowIcon;                   /* 18 */
-		pWindowCachedIcon WindowCachedIcon;       /* 19 */
-		pWindowDelete WindowDelete;               /* 20 */
-		pNotifyIconCreate NotifyIconCreate;       /* 21 */
-		pNotifyIconUpdate NotifyIconUpdate;       /* 22 */
-		pNotifyIconDelete NotifyIconDelete;       /* 23 */
-		pMonitoredDesktop MonitoredDesktop;       /* 24 */
-		pNonMonitoredDesktop NonMonitoredDesktop; /* 25 */
+		WINPR_ATTR_NODISCARD pWindowCreate WindowCreate;               /* 16 */
+		WINPR_ATTR_NODISCARD pWindowUpdate WindowUpdate;               /* 17 */
+		WINPR_ATTR_NODISCARD pWindowIcon WindowIcon;                   /* 18 */
+		WINPR_ATTR_NODISCARD pWindowCachedIcon WindowCachedIcon;       /* 19 */
+		WINPR_ATTR_NODISCARD pWindowDelete WindowDelete;               /* 20 */
+		WINPR_ATTR_NODISCARD pNotifyIconCreate NotifyIconCreate;       /* 21 */
+		WINPR_ATTR_NODISCARD pNotifyIconUpdate NotifyIconUpdate;       /* 22 */
+		WINPR_ATTR_NODISCARD pNotifyIconDelete NotifyIconDelete;       /* 23 */
+		WINPR_ATTR_NODISCARD pMonitoredDesktop MonitoredDesktop;       /* 24 */
+		WINPR_ATTR_NODISCARD pNonMonitoredDesktop NonMonitoredDesktop; /* 25 */
 		UINT32 paddingB[32 - 26];                 /* 26 */
 	};
 	typedef struct rdp_window_update rdpWindowUpdate;