diff --git a/lib/modules/Thread.pmod b/lib/modules/Thread.pmod
index faf0d5999a22383a0879137d2514cf7df9d8e594..0bdd21a9a2d6a4ce72dbb7f19c4b78dea07c250f 100644
--- a/lib/modules/Thread.pmod
+++ b/lib/modules/Thread.pmod
@@ -17,7 +17,7 @@ class Fifo {
       object key=lock::lock();
       while(!num) r_cond::wait(key);
       tmp=buffer[ptr++];
-      r_ptr%=sizeof(buffer);
+      ptr%=sizeof(buffer);
       num--;
       w_cond::signal();
       return tmp;