diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3080e7e..112570c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,2 +1,4 @@
-idf_component_register(SRCS "blk_box.c"
-                    INCLUDE_DIRS "include")
+idf_component_register(
+    SRCS "blk_box.cpp"
+    INCLUDE_DIRS "include"
+)
diff --git a/blk_box.c b/blk_box.c
deleted file mode 100644
index e15d180..0000000
--- a/blk_box.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <stdio.h>
-#include "blk_box.h"
-
-void func(void)
-{
-    
-}
diff --git a/blk_box.cpp b/blk_box.cpp
new file mode 100644
index 0000000..3982225
--- /dev/null
+++ b/blk_box.cpp
@@ -0,0 +1,6 @@
+#include <stdio.h>
+#include "blk_box.h"
+
+const char* get_hello_world() {
+    return "hello, world!";
+}
diff --git a/include/blk_box.h b/include/blk_box.h
index f6f3a61..bd56e5d 100644
--- a/include/blk_box.h
+++ b/include/blk_box.h
@@ -1 +1 @@
-void func(void);
+const char* get_hello_world();