diff --git a/utils/threadpool/threadpool.h b/utils/threadpool/threadpool.h
index a000f060b..f11bb4b2b 100644
--- a/utils/threadpool/threadpool.h
+++ b/utils/threadpool/threadpool.h
@@ -145,7 +145,7 @@ public:
 
     /** @brief Wait for a specific thread
       */
-    EXPORT void join(std::vector<uint64_t> thrHandle);
+    EXPORT void join(std::vector<uint64_t>& thrHandle);
 
     /** @brief for use in debugging
       */