diff --git a/include/utils/threads.h b/include/utils/threads.h
index 0bd69cf..432805e 100644
--- a/include/utils/threads.h
+++ b/include/utils/threads.h
@@ -510,6 +510,10 @@
     // that case.
             status_t    requestExitAndWait();
 
+    // Wait until this object's thread exits. Returns immediately if not yet running.
+    // Do not call from this object's thread; will return WOULD_BLOCK in that case.
+            status_t    join();
+
 protected:
     // exitPending() returns true if requestExit() has been called.
             bool        exitPending() const;