diff --git a/src/computer.h b/src/computer.h
index e556991..44bb37b 100644
--- a/src/computer.h
+++ b/src/computer.h
@@ -5,6 +5,7 @@
 
 typedef struct nn_computer {
     char state;
+    nn_guard *lock;
     nn_component *components;
     size_t componentLen;
     size_t componentCap;