diff --git a/src/if_py_both.h b/src/if_py_both.h
index c25be53..280c248 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -22,6 +22,7 @@
 #else
 # define ENC_OPT "latin1"
 #endif
+#define DOPY_FUNC "_vim_pydo"
 
 #define PyErr_SetVim(str) PyErr_SetString(VimError, str)