diff --git a/include/dix.h b/include/dix.h
index 893338f14..3d09bbe13 100644
--- a/include/dix.h
+++ b/include/dix.h
@@ -300,7 +300,7 @@ extern _X_EXPORT Bool ValidAtom(
 extern _X_EXPORT const char *NameForAtom(
     Atom /*atom*/);
 
-extern _X_EXPORT void AtomError(void);
+extern _X_EXPORT void AtomError(void) _X_NORETURN;
 
 extern _X_EXPORT void FreeAllAtoms(void);
 
diff --git a/include/dixstruct.h b/include/dixstruct.h
index 5b1a6981d..96104275d 100644
--- a/include/dixstruct.h
+++ b/include/dixstruct.h
@@ -53,7 +53,7 @@ typedef void (*ReplySwapPtr) (
 extern _X_EXPORT void ReplyNotSwappd (
 		ClientPtr	/* pClient */,
 		int		/* size */,
-		void *		/* pbuf */);
+		void *		/* pbuf */) _X_NORETURN;
 
 typedef enum {ClientStateInitial,
 	      ClientStateAuthenticating,
diff --git a/include/extnsionst.h b/include/extnsionst.h
index 19c76fcc4..bb66dfb6e 100644
--- a/include/extnsionst.h
+++ b/include/extnsionst.h
@@ -84,7 +84,7 @@ extern _X_EXPORT EventSwapPtr EventSwapVector[128];
 
 extern _X_EXPORT void NotImplemented (	/* FIXME: this may move to another file... */
 	xEvent *,
-	xEvent *);
+	xEvent *) _X_NORETURN;
 
 #define    SetGCVector(pGC, VectorElement, NewRoutineAddress, Atom)    \
     pGC->VectorElement = NewRoutineAddress;