diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 31eea3c..61b9f52 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -112,8 +112,9 @@
 "'a' for appending (which on some Unix systems, means that all writes\n"
 "append to the end of the file regardless of the current seek position).\n"
 "In text mode, if encoding is not specified the encoding used is platform\n"
-"dependent. (For reading and writing raw bytes use binary mode and leave\n"
-"encoding unspecified.) The available modes are:\n"
+"dependent: locale.getpreferredencoding(False) is called to get the\n"
+"current locale encoding. (For reading and writing raw bytes use binary\n"
+"mode and leave encoding unspecified.) The available modes are:\n"
 "\n"
 "========= ===============================================================\n"
 "Character Meaning\n"
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index ae105e5..287f165 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -630,7 +630,7 @@
     "Character and line based layer over a BufferedIOBase object, buffer.\n"
     "\n"
     "encoding gives the name of the encoding that the stream will be\n"
-    "decoded or encoded with. It defaults to locale.getpreferredencoding.\n"
+    "decoded or encoded with. It defaults to locale.getpreferredencoding(False).\n"
     "\n"
     "errors determines the strictness of encoding and decoding (see the\n"
     "codecs.register) and defaults to \"strict\".\n"
@@ -898,7 +898,7 @@
         else {
           use_locale:
             self->encoding = _PyObject_CallMethodId(
-                state->locale_module, &PyId_getpreferredencoding, NULL);
+                state->locale_module, &PyId_getpreferredencoding, "O", Py_False);
             if (self->encoding == NULL) {
               catch_ImportError:
                 /*