diff --git a/Modules/_struct.c b/Modules/_struct.c
index 04d7f8e..66f74d6 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -1733,7 +1733,7 @@
  *
  */
 static int
-s_pack_internal(PyStructObject *soself, PyObject **args, int offset, char* buf)
+s_pack_internal(PyStructObject *soself, PyObject *const *args, int offset, char* buf)
 {
     formatcode *code;
     /* XXX(nnorwitz): why does i need to be a local?  can we use
@@ -1820,7 +1820,7 @@
 strings.");
 
 static PyObject *
-s_pack(PyObject *self, PyObject **args, Py_ssize_t nargs)
+s_pack(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
 {
     PyStructObject *soself;
     PyObject *result;
@@ -1859,7 +1859,7 @@
 help(struct) for more on format strings.");
 
 static PyObject *
-s_pack_into(PyObject *self, PyObject **args, Py_ssize_t nargs)
+s_pack_into(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
 {
     PyStructObject *soself;
     Py_buffer buffer;
@@ -2123,7 +2123,7 @@
 to the format string.  See help(struct) for more on format strings.");
 
 static PyObject *
-pack(PyObject *self, PyObject **args, Py_ssize_t nargs)
+pack(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
 {
     PyObject *s_object = NULL;
     PyObject *format, *result;
@@ -2151,7 +2151,7 @@
 on format strings.");
 
 static PyObject *
-pack_into(PyObject *self, PyObject **args, Py_ssize_t nargs)
+pack_into(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
 {
     PyObject *s_object = NULL;
     PyObject *format, *result;