diff --git a/include/rabit/c_api.h b/include/rabit/c_api.h
index a2a2a9706..07ee08663 100644
--- a/include/rabit/c_api.h
+++ b/include/rabit/c_api.h
@@ -140,6 +140,7 @@ RABIT_DLL int RabitVersionNumber();
  * // force link rabit C API library.
  * static int must_link_rabit_ = RabitLinkTag();
  * \endcode
+ * \return a dummy integer.
  */
 RABIT_DLL int RabitLinkTag();
 
diff --git a/test/test.mk b/test/test.mk
index 9dadadff0..4a5451130 100644
--- a/test/test.mk
+++ b/test/test.mk
@@ -26,4 +26,4 @@ lazy_recover_10_10k_die_same:
 	../dmlc-core/tracker/dmlc-submit --cluster local --num-workers=10 lazy_recover 10000 mock=0,0,1,0 mock=1,1,1,0 mock=0,1,1,0 mock=4,1,1,0 mock=9,1,1,0
 
 ringallreduce_10_10k:
-	../dmlc-core/tracker/dmlc-submit --cluster local -num-workers=10 model_recover 100 rabit_reduce_ring_mincount=10
+	../dmlc-core/tracker/dmlc-submit --cluster local --num-workers=10 model_recover 100 rabit_reduce_ring_mincount=10