Index: Modules/_ctypes/callproc.c
===================================================================
--- Modules/_ctypes/callproc.c	(revision 54885)
+++ Modules/_ctypes/callproc.c	(working copy)
@@ -1126,7 +1126,7 @@
 static PyObject *free_library(PyObject *self, PyObject *args)
 {
 	HMODULE hMod;
-	if (!PyArg_ParseTuple(args, "i:FreeLibrary", &hMod))
+	if (!PyArg_ParseTuple(args, PY_SSIZE_T_CODE ":FreeLibrary", &hMod))
 		return NULL;
 	if (!FreeLibrary(hMod))
 		return PyErr_SetFromWindowsErr(GetLastError());
@@ -1247,9 +1247,9 @@
 
 static PyObject *py_dl_close(PyObject *self, PyObject *args)
 {
-	int handle;
+	Py_ssize_t handle;
 
-	if (!PyArg_ParseTuple(args, "i:dlclose", &handle))
+	if (!PyArg_ParseTuple(args, PY_SSIZE_T_CODE ":dlclose", &handle))
 		return NULL;
 	if (dlclose((void*)handle)) {
 		PyErr_SetString(PyExc_OSError,
@@ -1263,10 +1263,10 @@
 static PyObject *py_dl_sym(PyObject *self, PyObject *args)
 {
 	char *name;
-	int handle;
+	Py_ssize_t handle;
 	void *ptr;
 
-	if (!PyArg_ParseTuple(args, "is:dlsym", &handle, &name))
+	if (!PyArg_ParseTuple(args, PY_SSIZE_T_CODE "s:dlsym", &handle, &name))
 		return NULL;
 	ptr = ctypes_dlsym((void*)handle, name);
 	if (!ptr) {
@@ -1286,12 +1286,12 @@
 static PyObject *
 call_function(PyObject *self, PyObject *args)
 {
-	int func;
+	Py_ssize_t func;
 	PyObject *arguments;
 	PyObject *result;
 
 	if (!PyArg_ParseTuple(args,
-			      "iO!",
+			      PY_SSIZE_T_CODE "O!",
 			      &func,
 			      &PyTuple_Type, &arguments))
 		return NULL;
@@ -1317,12 +1317,12 @@
 static PyObject *
 call_cdeclfunction(PyObject *self, PyObject *args)
 {
-	int func;
+	Py_ssize_t func;
 	PyObject *arguments;
 	PyObject *result;
 
 	if (!PyArg_ParseTuple(args,
-			      "iO!",
+			      PY_SSIZE_T_CODE "O!",
 			      &func,
 			      &PyTuple_Type, &arguments))
 		return NULL;
Index: Modules/_ctypes/ctypes.h
===================================================================
--- Modules/_ctypes/ctypes.h	(revision 54885)
+++ Modules/_ctypes/ctypes.h	(working copy)
@@ -4,6 +4,9 @@
 
 #if (PY_VERSION_HEX < 0x02050000)
 typedef int Py_ssize_t;
+#define PY_SSIZE_T_CODE "i"
+#else
+#define PY_SSIZE_T_CODE "n"
 #endif
 
 #ifndef MS_WIN32