diff --git a/src/os_unix.c b/src/os_unix.c
index 5bcac85..194e4d3 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -4594,7 +4594,7 @@
 
     // Only require pressing Enter when redrawing, to avoid that system() gets
     // the hit-enter prompt even though it didn't output anything.
-    if (!RedrawingDisabled)
+    if (RedrawingDisabled == 0)
 	wait_return(TRUE);
     do_buffer(DOBUF_WIPE, DOBUF_FIRST, FORWARD, buf->b_fnum, TRUE);