diff --git a/lib/cpp/src/thrift/server/TNonblockingServer.cpp b/lib/cpp/src/thrift/server/TNonblockingServer.cpp
index 8590bff..631c2d5 100644
--- a/lib/cpp/src/thrift/server/TNonblockingServer.cpp
+++ b/lib/cpp/src/thrift/server/TNonblockingServer.cpp
@@ -1106,7 +1106,7 @@
 
   if (!port_) {
     sockaddr_in addr;
-    unsigned int size = sizeof(addr);
+    socklen_t size = sizeof(addr);
     if (!getsockname(serverSocket_, reinterpret_cast<sockaddr*>(&addr), &size)) {
       listenPort_ = ntohs(addr.sin_port);
     } else {