diff --git a/lib/cpp/src/thrift/server/TNonblockingServer.cpp b/lib/cpp/src/thrift/server/TNonblockingServer.cpp
index 7bd42e2..86a96c6 100644
--- a/lib/cpp/src/thrift/server/TNonblockingServer.cpp
+++ b/lib/cpp/src/thrift/server/TNonblockingServer.cpp
@@ -265,7 +265,7 @@
    * @param v void* callback arg where we placed TConnection's "this".
    */
   static void eventHandler(evutil_socket_t fd, short /* which */, void* v) {
-    assert(fd == ((TConnection*)v)->getTSocket()->getSocketFD());
+    assert(fd == static_cast<evutil_socket_t>(((TConnection*)v)->getTSocket()->getSocketFD()));
     ((TConnection*)v)->workSocket();
   }