1 files changed, 1 insertions, 0 deletions
diff --git a/gr-blocks/include/blocks/control_loop.h b/gr-blocks/include/blocks/control_loop.h
index e59429a1f7..475b28f944 100644
--- a/gr-blocks/include/blocks/control_loop.h
+++ b/gr-blocks/include/blocks/control_loop.h
@@ -37,6 +37,7 @@ namespace gr {
       float d_alpha, d_beta;
 
     public:
+      control_loop(void) {}
       control_loop(float loop_bw, float max_freq, float min_freq);
       virtual ~control_loop();