diff --git a/examples/protocols/asio/asio_chat/main/chat_message.hpp b/examples/protocols/asio/asio_chat/main/chat_message.hpp
index 629105b05b..a6ffc83b8c 100644
--- a/examples/protocols/asio/asio_chat/main/chat_message.hpp
+++ b/examples/protocols/asio/asio_chat/main/chat_message.hpp
@@ -18,8 +18,8 @@
 class chat_message
 {
 public:
-  enum { header_length = 4 };
-  enum { max_body_length = 512 };
+  static constexpr std::size_t header_length = 4;
+  static constexpr std::size_t max_body_length = 512;
 
   chat_message()
     : body_length_(0)