diff --git a/cextern/helloworld.c b/cextern/helloworld.c
new file mode 100644
index 0000000000000000000000000000000000000000..6c28d43fe5cc99e9139b46d8c4196fe82a3a92a3
--- /dev/null
+++ b/cextern/helloworld.c
@@ -0,0 +1,15 @@
+// Simple C program to display "Hello World"
+
+// Header file for input output functions
+#include <stdio.h>
+
+// main function -
+// where the execution of program begins
+int main()
+{
+
+    // prints hello world
+    printf("Hello World");
+
+    return 0;
+}
\ No newline at end of file
diff --git a/install_local.sh b/install_local.sh
index 7e0632543d0d28529d9cecda8aa81938e8bac690..f34deebdf22b60bc5cb34d34e227bcb14440ee93 100644
--- a/install_local.sh
+++ b/install_local.sh
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 rm -rf build
 rm -rf dist
-#python setup.py build_ext --inplace
+python setup.py build_ext
 #python setup.py install
 python setup.py sdist
 pip install dist/*.tar.gz --force-reinstall
diff --git a/setup.py b/setup.py
index 366e9b05458dd0010f42d0a6f238af80cd7f39c2..70a1a8cdf02e2059f9a82584f8a6337be9efd9d4 100644
--- a/setup.py
+++ b/setup.py
@@ -37,4 +37,9 @@ setuptools.setup(
     #                   'astropy',
     #                   ],
     python_requires='>=3.9',
-)
+    ext_modules=[
+        setuptools.Extension(
+            name="csst_proto.cext.helloworld", sources=["cextern/helloworld.c"]
+        )
+    ]
+)
\ No newline at end of file