diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
index 1111021e1852b3..54cddf4b0929f2 100644
--- a/Modules/_testcapi/parts.h
+++ b/Modules/_testcapi/parts.h
@@ -1,3 +1,3 @@
 #include "Python.h"
 
-PyAPI_FUNC(int) _PyTestCapi_Init_Vectorcall(PyObject *module);
+int _PyTestCapi_Init_Vectorcall(PyObject *module);