diff --git a/src/message.c b/src/message.c
index 07566da..02380e9 100644
--- a/src/message.c
+++ b/src/message.c
@@ -949,8 +949,10 @@
     int		n;
     int		room;
 
+    // If something unexpected happened "room" may be negative, check for that
+    // just in case.
     room = (int)(Rows - cmdline_row - 1) * Columns + sc_col - 1;
-    if ((force || (shortmess(SHM_TRUNC) && !exmode_active))
+    if (room > 0 && (force || (shortmess(SHM_TRUNC) && !exmode_active))
 	    && (n = (int)STRLEN(s) - room) > 0)
     {
 	if (has_mbyte)