diff --git a/lib/c_glib/test/testthrifttestclient.cpp b/lib/c_glib/test/testthrifttestclient.cpp
index 77cd24a..513f071 100644
--- a/lib/c_glib/test/testthrifttestclient.cpp
+++ b/lib/c_glib/test/testthrifttestclient.cpp
@@ -112,8 +112,8 @@
     out = thing;
   }
 
-  std::string testUuid(const std::string thing) override {
-    cout << "[C -> C++] testUuid(\"" << std::hex << thing << "\")" << '\n';
+  apache::thrift::TUuid testUuid(const apache::thrift::TUuid thing) override {
+    cout << "[C -> C++] testUuid(\"" << thing << "\")" << '\n';
     return thing;
   }
 
diff --git a/lib/c_glib/test/testthrifttestzlibclient.cpp b/lib/c_glib/test/testthrifttestzlibclient.cpp
index 7c0f24a..dbcd64e 100644
--- a/lib/c_glib/test/testthrifttestzlibclient.cpp
+++ b/lib/c_glib/test/testthrifttestzlibclient.cpp
@@ -107,8 +107,8 @@
     out = thing;
   }
 
-  std::string testUuid(const std::string thing) override {
-    cout << "[C -> C++] testUuid(\"" << std::hex << thing << "\")" << '\n';
+  apache::thrift::TUuid testUuid(const apache::thrift::TUuid thing) override {
+    cout << "[C -> C++] testUuid(\"" << thing << "\")" << '\n';
     return thing;
   }