diff --git a/lib/cpp/src/concurrency/Mutex.cpp b/lib/cpp/src/concurrency/Mutex.cpp
index 0cfa0ad..332d415 100644
--- a/lib/cpp/src/concurrency/Mutex.cpp
+++ b/lib/cpp/src/concurrency/Mutex.cpp
@@ -154,6 +154,7 @@
     PROFILE_MUTEX_NOT_LOCKED();
     return false;
 #else
+    (void)milliseconds;
     // If pthread_mutex_timedlock isn't supported, the safest thing to do
     // is just do a nonblocking trylock.
     return trylock();