diff --git a/src/signalhandler_unittest.cc b/src/signalhandler_unittest.cc
index 8dae5f5ca..59be2315f 100644
--- a/src/signalhandler_unittest.cc
+++ b/src/signalhandler_unittest.cc
@@ -43,7 +43,7 @@
 
 #ifdef HAVE_LIB_GFLAGS
 #include <gflags/gflags.h>
-using namespace gflags;
+using namespace GFLAGS_NAMESPACE;
 #endif
 
 using namespace GOOGLE_NAMESPACE;