diff --git a/Python/frozenmain.c b/Python/frozenmain.c
index c56938a..76309e9 100644
--- a/Python/frozenmain.c
+++ b/Python/frozenmain.c
@@ -40,6 +40,7 @@
     }
 
     PyConfig config;
+    config.struct_size = sizeof(PyConfig);
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
         PyConfig_Clear(&config);