diff --git a/examples/threading/producer-consumer.scm b/examples/threading/producer-consumer.scm
index c4398624..42344066 100644
--- a/examples/threading/producer-consumer.scm
+++ b/examples/threading/producer-consumer.scm
@@ -34,7 +34,8 @@
     ;;   control flow problem
     ;; - try compiling this but commenting out the Cyc_mutex_lock
     ;;   code in the C. there is a gc_move bag tag error at runtime
-    (mutex-lock! *lock*)`
+    ;;   also get the same result by using read-char below... WTF?
+    (read-char) ;(mutex-lock! *lock*)`
     (cond
       ((not (null? *queue*))
        (write (car *queue*))