diff --git a/cpp/utils.cc b/cpp/utils.cc
index 8575284..592a48c 100644
--- a/cpp/utils.cc
+++ b/cpp/utils.cc
@@ -283,7 +283,7 @@ namespace f8
         std::vector<std::string> strings;
         a8::Split(sessionid, strings, '_');
         if (strings.size() < 4) {
-            return false;
+            return 0;
         }
         std::string session_createtime = strings[0];
         std::string account_registertime = strings[1];