diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index c2c217d..347982c 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -193,6 +193,10 @@
   return 4;
 }
 
+void ExampleAppBeep(IPDF_JSPLATFORM*, int type) {
+  printf("BEEP!!! %d\n", type);
+}
+
 void ExampleDocGotoPage(IPDF_JSPLATFORM*, int page_number) {
   printf("Goto Page: %d\n", page_number);
 }
@@ -682,6 +686,7 @@
   platform_callbacks.version = 3;
   platform_callbacks.app_alert = ExampleAppAlert;
   platform_callbacks.app_response = ExampleAppResponse;
+  platform_callbacks.app_beep = ExampleAppBeep;
   platform_callbacks.Doc_gotoPage = ExampleDocGotoPage;
   platform_callbacks.Doc_mail = ExampleDocMail;