1 files changed, 1 insertions, 0 deletions
diff --git a/gnuradio-runtime/lib/hier_block2_detail.h b/gnuradio-runtime/lib/hier_block2_detail.h
index 8c38c3754a..a5584fe92a 100644
--- a/gnuradio-runtime/lib/hier_block2_detail.h
+++ b/gnuradio-runtime/lib/hier_block2_detail.h
@@ -71,6 +71,7 @@ namespace gr {
     endpoint_vector_t d_outputs;             // Single internal endpoint per external output
     basic_block_vector_t d_blocks;
 
+    void refresh_io_signature();
     void connect_input(int my_port, int port, basic_block_sptr block);
     void connect_output(int my_port, int port, basic_block_sptr block);
     void disconnect_input(int my_port, int port, basic_block_sptr block);