diff --git a/Include/fileutils.h b/Include/fileutils.h
index 21eefde..e4bf6d4 100644
--- a/Include/fileutils.h
+++ b/Include/fileutils.h
@@ -152,6 +152,9 @@
 PyAPI_FUNC(int) _Py_set_inheritable(int fd, int inheritable,
                                     int *atomic_flag_works);
 
+PyAPI_FUNC(int) _Py_set_inheritable_async_safe(int fd, int inheritable,
+                                               int *atomic_flag_works);
+
 PyAPI_FUNC(int) _Py_dup(int fd);
 
 #ifndef MS_WINDOWS