diff --git a/sim/SimSelect.c b/sim/SimSelect.c
index db0ffebd..41290dea 100644
--- a/sim/SimSelect.c
+++ b/sim/SimSelect.c
@@ -445,7 +445,7 @@ SimSelection(cmd)
     char		*strPtr;
     bool		goodReply;
 
-    extern 		RsimErrorMsg();
+    extern void		RsimErrorMsg();
 
     timeString[0] = 0;