diff --git a/src/XlibInt.c b/src/XlibInt.c
index 4c8eaeb7..075648e6 100644
--- a/src/XlibInt.c
+++ b/src/XlibInt.c
@@ -1238,7 +1238,7 @@ _XWireToEvent(
  * _XDefaultIOError - Default fatal system error reporting routine.  Called
  * when an X internal system error is encountered.
  */
-int _XDefaultIOError(
+_X_NORETURN int _XDefaultIOError(
 	Display *dpy)
 {
 	if (ECHECK(EPIPE)) {