diff --git a/lib/cpp/test/JSONProtoTest.cpp b/lib/cpp/test/JSONProtoTest.cpp
index dcb34d1..be8f426 100644
--- a/lib/cpp/test/JSONProtoTest.cpp
+++ b/lib/cpp/test/JSONProtoTest.cpp
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+#define _USE_MATH_DEFINES
 #include <iostream>
 #include <cmath>
 #include <thrift/transport/TBufferTransports.h>