1 files changed, 1 insertions, 1 deletions
diff --git a/gr-blocks/lib/delay_impl.h b/gr-blocks/lib/delay_impl.h
index cba81542cc..c58de83668 100644
--- a/gr-blocks/lib/delay_impl.h
+++ b/gr-blocks/lib/delay_impl.h
@@ -22,7 +22,7 @@ class delay_impl : public delay
 private:
     void forecast(int noutput_items, gr_vector_int& ninput_items_required);
 
-    size_t d_itemsize;
+    const size_t d_itemsize;
     int d_delta;
     gr::thread::mutex d_mutex_delay;