diff --git a/src/ls.c b/src/ls.c
index f248ff7d9..f3d5e891a 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -1400,7 +1400,7 @@ decode_switches (int argc, char **argv)
     struct winsize ws;
 
     if (ioctl (STDOUT_FILENO, TIOCGWINSZ, &ws) != -1
-	&& 0 < ws.ws_col && ws.ws_col <= SIZE_MAX)
+	&& 0 < ws.ws_col && ws.ws_col == (size_t) ws.ws_col)
       line_length = ws.ws_col;
   }
 #endif