diff -r cac63f6ad252 Lib/test/test_io.py
--- a/Lib/test/test_io.py	Mon Apr 16 21:34:24 2012 -0600
+++ b/Lib/test/test_io.py	Tue Apr 17 10:23:45 2012 +0100
@@ -282,6 +282,7 @@
         self.assertEqual(f.write(b"Hello."), 6)
         self.assertEqual(f.tell(), 6)
         self.assertEqual(f.seek(-1, 1), 5)
+        self.assertEqual(f.seek(-1, whence=1), 5)
         self.assertEqual(f.tell(), 5)
         self.assertEqual(f.write(bytearray(b" world\n\n\n")), 9)
         self.assertEqual(f.seek(0), 0)
@@ -291,6 +292,8 @@
 
         self.assertEqual(f.truncate(12), 12)
         self.assertEqual(f.tell(), 13)
+        self.assertEqual(f.truncate(size=11), 11)
+        self.assertEqual(f.tell(), 12)
         self.assertRaises(TypeError, f.seek, 0.0)
 
     def read_ops(self, f, buffered=False):
@@ -399,6 +402,7 @@
             self.assertEqual(f.readline(), b"abc\n")
             self.assertEqual(f.readline(10), b"def\n")
             self.assertEqual(f.readline(2), b"xy")
+            self.assertEqual(f.readline(limit=2), b"xy")
             self.assertEqual(f.readline(4), b"zzy\n")
             self.assertEqual(f.readline(), b"foo\x00bar\n")
             self.assertEqual(f.readline(None), b"another line")
@@ -857,6 +861,7 @@
             return self.tp(rawio)
         self.assertEqual(bufio().readlines(), [b"abc\n", b"d\n", b"ef"])
         self.assertEqual(bufio().readlines(5), [b"abc\n", b"d\n"])
+        self.assertEqual(bufio().readlines(hint=5), [b"abc\n", b"d\n"])
         self.assertEqual(bufio().readlines(None), [b"abc\n", b"d\n", b"ef"])
 
     def test_buffering(self):
diff -r cac63f6ad252 Modules/_io/fileio.c
--- a/Modules/_io/fileio.c	Mon Apr 16 21:34:24 2012 -0600
+++ b/Modules/_io/fileio.c	Tue Apr 17 10:23:45 2012 +0100
@@ -686,19 +686,22 @@
 }
 
 static PyObject *
-fileio_read(fileio *self, PyObject *args)
+fileio_read(fileio *self, PyObject *args, PyObject *kwds)
 {
     char *ptr;
     Py_ssize_t n;
     Py_ssize_t size = -1;
     PyObject *bytes;
+    static char *kwlist[] = {"n", NULL};
 
     if (self->fd < 0)
         return err_closed();
     if (!self->readable)
         return err_mode("reading");
 
-    if (!PyArg_ParseTuple(args, "|O&", &_PyIO_ConvertSsize_t, &size))
+    if (!PyArg_ParseTupleAndKeywords(args, kwds,
+                                     "|O&", kwlist,
+                                     &_PyIO_ConvertSsize_t, &size))
         return NULL;
 
     if (size < 0) {
@@ -857,15 +860,18 @@
 }
 
 static PyObject *
-fileio_seek(fileio *self, PyObject *args)
+fileio_seek(fileio *self, PyObject *args, PyObject *kwds)
 {
     PyObject *posobj;
     int whence = 0;
+    static char *kwlist[] = {"offset", "whence", NULL};
 
     if (self->fd < 0)
         return err_closed();
 
-    if (!PyArg_ParseTuple(args, "O|i", &posobj, &whence))
+    if (!PyArg_ParseTupleAndKeywords(args, kwds,
+                                     "O|i", kwlist,
+                                     &posobj, &whence))
         return NULL;
 
     return portable_lseek(self->fd, posobj, whence);
@@ -882,9 +888,10 @@
 
 #ifdef HAVE_FTRUNCATE
 static PyObject *
-fileio_truncate(fileio *self, PyObject *args)
+fileio_truncate(fileio *self, PyObject *args, PyObject *kwds)
 {
     PyObject *posobj = NULL; /* the new size wanted by the user */
+    static char *kwlist[] = {"size", NULL};
 #ifndef MS_WINDOWS
     Py_off_t pos;
 #endif
@@ -897,7 +904,7 @@
     if (!self->writable)
         return err_mode("writing");
 
-    if (!PyArg_ParseTuple(args, "|O", &posobj))
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|O", kwlist, &posobj))
         return NULL;
 
     if (posobj == Py_None || posobj == NULL) {
@@ -1133,16 +1140,16 @@
 "writable() -> bool.  True if file was opened in a write mode.");
 
 static PyMethodDef fileio_methods[] = {
-    {"read",     (PyCFunction)fileio_read,         METH_VARARGS, read_doc},
+    {"read",     (PyCFunction)fileio_read,     METH_VARARGS, read_doc},
     {"readall",  (PyCFunction)fileio_readall,  METH_NOARGS,  readall_doc},
     {"readinto", (PyCFunction)fileio_readinto, METH_VARARGS, readinto_doc},
-    {"write",    (PyCFunction)fileio_write,        METH_VARARGS, write_doc},
-    {"seek",     (PyCFunction)fileio_seek,         METH_VARARGS, seek_doc},
-    {"tell",     (PyCFunction)fileio_tell,         METH_VARARGS, tell_doc},
+    {"write",    (PyCFunction)fileio_write,    METH_VARARGS, write_doc},
+    {"seek",     (PyCFunction)fileio_seek,     METH_VARARGS | METH_KEYWORDS, seek_doc},
+    {"tell",     (PyCFunction)fileio_tell,     METH_VARARGS, tell_doc},
 #ifdef HAVE_FTRUNCATE
-    {"truncate", (PyCFunction)fileio_truncate, METH_VARARGS, truncate_doc},
+    {"truncate", (PyCFunction)fileio_truncate, METH_VARARGS | METH_KEYWORDS, truncate_doc},
 #endif
-    {"close",    (PyCFunction)fileio_close,        METH_NOARGS,  close_doc},
+    {"close",    (PyCFunction)fileio_close,    METH_NOARGS,  close_doc},
     {"seekable", (PyCFunction)fileio_seekable, METH_NOARGS,      seekable_doc},
     {"readable", (PyCFunction)fileio_readable, METH_NOARGS,      readable_doc},
     {"writable", (PyCFunction)fileio_writable, METH_NOARGS,      writable_doc},
@@ -1150,7 +1157,7 @@
     {"isatty",   (PyCFunction)fileio_isatty,   METH_NOARGS,      isatty_doc},
     {"_dealloc_warn", (PyCFunction)fileio_dealloc_warn, METH_O, NULL},
     {"__getstate__", (PyCFunction)fileio_getstate, METH_NOARGS, NULL},
-    {NULL,           NULL}             /* sentinel */
+    {NULL,           NULL, 0, NULL}             /* sentinel */
 };
 
 /* 'closed' and 'mode' are attributes for backwards compatibility reasons. */
diff -r cac63f6ad252 Modules/_io/iobase.c
--- a/Modules/_io/iobase.c	Mon Apr 16 21:34:24 2012 -0600
+++ b/Modules/_io/iobase.c	Tue Apr 17 10:23:45 2012 +0100
@@ -87,7 +87,7 @@
     "Return the new absolute position.");
 
 static PyObject *
-iobase_seek(PyObject *self, PyObject *args)
+iobase_seek(PyObject *self, PyObject *args, PyObject *kwds)
 {
     return iobase_unsupported("seek");
 }
@@ -110,7 +110,7 @@
     "position as reported by tell().  Returns the new size.");
 
 static PyObject *
-iobase_truncate(PyObject *self, PyObject *args)
+iobase_truncate(PyObject *self, PyObject *args, PyObject *kwds)
 {
     return iobase_unsupported("truncate");
 }
@@ -447,10 +447,11 @@
     "terminator(s) recognized.\n");
 
 static PyObject *
-iobase_readline(PyObject *self, PyObject *args)
+iobase_readline(PyObject *self, PyObject *args, PyObject *kwds)
 {
     /* For backwards compatibility, a (slowish) readline(). */
 
+    static char *kwlist[] = {"limit", NULL};
     Py_ssize_t limit = -1;
     int has_peek = 0;
     PyObject *buffer, *result;
@@ -458,7 +459,9 @@
     _Py_IDENTIFIER(read);
     _Py_IDENTIFIER(peek);
 
-    if (!PyArg_ParseTuple(args, "|O&:readline", &_PyIO_ConvertSsize_t, &limit)) {
+    if (!PyArg_ParseTupleAndKeywords(args, kwds,
+                                     "|O&:readline", kwlist,
+                                     &_PyIO_ConvertSsize_t, &limit)) {
         return NULL;
     }
 
@@ -579,12 +582,15 @@
     "lines so far exceeds hint.");
 
 static PyObject *
-iobase_readlines(PyObject *self, PyObject *args)
+iobase_readlines(PyObject *self, PyObject *args, PyObject *kwds)
 {
+    static char *kwlist[] = {"hint", NULL};
     Py_ssize_t hint = -1, length = 0;
     PyObject *result;
 
-    if (!PyArg_ParseTuple(args, "|O&:readlines", &_PyIO_ConvertSsize_t, &hint)) {
+    if (!PyArg_ParseTupleAndKeywords(args, kwds,
+                                     "|O&:readlines", kwlist,
+                                     &_PyIO_ConvertSsize_t, &hint)) {
         return NULL;
     }
 
@@ -672,11 +678,11 @@
 }
 
 static PyMethodDef iobase_methods[] = {
-    {"seek", iobase_seek, METH_VARARGS, iobase_seek_doc},
-    {"tell", iobase_tell, METH_NOARGS, iobase_tell_doc},
-    {"truncate", iobase_truncate, METH_VARARGS, iobase_truncate_doc},
-    {"flush", iobase_flush, METH_NOARGS, iobase_flush_doc},
-    {"close", iobase_close, METH_NOARGS, iobase_close_doc},
+    {"seek",     iobase_seek,     METH_VARARGS | METH_KEYWORDS, iobase_seek_doc},
+    {"tell",     iobase_tell,     METH_NOARGS,  iobase_tell_doc},
+    {"truncate", iobase_truncate, METH_VARARGS | METH_KEYWORDS, iobase_truncate_doc},
+    {"flush",    iobase_flush,    METH_NOARGS,  iobase_flush_doc},
+    {"close",    iobase_close,    METH_NOARGS,  iobase_close_doc},
 
     {"seekable", iobase_seekable, METH_NOARGS, iobase_seekable_doc},
     {"readable", iobase_readable, METH_NOARGS, iobase_readable_doc},
@@ -693,8 +699,8 @@
     {"__enter__", iobase_enter, METH_NOARGS},
     {"__exit__", iobase_exit, METH_VARARGS},
 
-    {"readline", iobase_readline, METH_VARARGS, iobase_readline_doc},
-    {"readlines", iobase_readlines, METH_VARARGS, iobase_readlines_doc},
+    {"readline",   iobase_readline,  METH_VARARGS | METH_KEYWORDS, iobase_readline_doc},
+    {"readlines",  iobase_readlines, METH_VARARGS | METH_KEYWORDS, iobase_readlines_doc},
     {"writelines", iobase_writelines, METH_VARARGS},
 
     {NULL, NULL}