diff --git a/FFX_CAS/cas-samples/libs/cauldron/src/common/Misc/threadpool.h b/FFX_CAS/cas-samples/libs/cauldron/src/common/Misc/threadpool.h
index 2c3d058..28a6289 100644
--- a/FFX_CAS/cas-samples/libs/cauldron/src/common/Misc/threadpool.h
+++ b/FFX_CAS/cas-samples/libs/cauldron/src/common/Misc/threadpool.h
@@ -24,6 +24,7 @@
 #include <mutex>
 #include <deque>
 #include <condition_variable>
+#include <functional>
 
 struct Task
 {