diff --git a/pid/pidthread.hpp b/pid/pidthread.hpp
index 670d558..37c416a 100644
--- a/pid/pidthread.hpp
+++ b/pid/pidthread.hpp
@@ -3,4 +3,4 @@
 #include "pid/zone.hpp"
 
 /* Given a zone, run through the loops. */
-void PIDControlThread(std::shared_ptr<PIDZone> zone);
+void PIDControlThread(PIDZone* zone);