Index: Doc/library/os.path.rst
===================================================================
--- Doc/library/os.path.rst	(revision 83101)
+++ Doc/library/os.path.rst	(working copy)
@@ -249,9 +249,11 @@
 
    Return ``True`` if the file descriptors *fp1* and *fp2* refer to the same file.
 
-   Availability: Unix.
+   Availability: Unix, Windows.
 
+   .. versionchanged:: 3.2 Added Windows support.
 
+
 .. function:: samestat(stat1, stat2)
 
    Return ``True`` if the stat tuples *stat1* and *stat2* refer to the same file.
Index: Lib/ntpath.py
===================================================================
--- Lib/ntpath.py	(revision 83101)
+++ Lib/ntpath.py	(working copy)
@@ -10,6 +10,7 @@
 import stat
 import genericpath
 from genericpath import *
+from nt import _getfileinformation
 
 __all__ = ["normcase","isabs","join","splitdrive","split","splitext",
            "basename","dirname","commonprefix","getsize","getmtime",
@@ -17,7 +18,7 @@
            "ismount", "expanduser","expandvars","normpath","abspath",
            "splitunc","curdir","pardir","sep","pathsep","defpath","altsep",
            "extsep","devnull","realpath","supports_unicode_filenames","relpath",
-           "samefile",]
+           "samefile", "sameopenfile",]
 
 # strings representing various path-related bits and pieces
 # These are primarily for export; internally, they are hardcoded.
@@ -639,3 +640,7 @@
         # Also, on other operating systems, fake this method with a
         #  Windows-XP approximation.
         return abspath(f1) == abspath(f2)
+
+def sameopenfile(f1, f2):
+    """Test whether two file objects reference the same file"""
+    return _getfileinformation(f1) == _getfileinformation(f2)
Index: Lib/test/test_ntpath.py
===================================================================
--- Lib/test/test_ntpath.py	(revision 83101)
+++ Lib/test/test_ntpath.py	(working copy)
@@ -2,6 +2,7 @@
 import os
 from test.support import TestFailed
 from test import support, test_genericpath
+from tempfile import TemporaryFile
 import unittest
 
 
@@ -233,8 +234,20 @@
         tester('ntpath.relpath("/", "/")', '.')
         tester('ntpath.relpath("/a", "/a")', '.')
         tester('ntpath.relpath("/a/b", "/a/b")', '.')
+    
+    def test_sameopenfile(self):
+        with TemporaryFile() as tf1, TemporaryFile() as tf2:
+            # Make sure the same file is really the same
+            self.assertTrue(ntpath.sameopenfile(tf1.fileno(), tf1.fileno()))
+            # Make sure different files are really different
+            self.assertFalse(ntpath.sameopenfile(tf1.fileno(), tf2.fileno()))
+            # Make sure invalid values don't cause issues
+            with self.assertRaises(ValueError):
+                # Invalid file descriptors shouldn't display assert
+                # dialogs (#4804) 
+                ntpath.sameopenfile(-1, -1)
+            
 
-
 class NtCommonTest(test_genericpath.CommonTest):
     pathmodule = ntpath
     attributes = ['relpath', 'splitunc']
Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(revision 83101)
+++ Modules/posixmodule.c	(working copy)
@@ -2736,6 +2736,34 @@
     return result;
 
 } /* end of posix__getfinalpathname */
+
+static PyObject *
+posix__getfileinformation(PyObject *self, PyObject *args)
+{
+    HANDLE hFile;
+    BY_HANDLE_FILE_INFORMATION info;
+    int fd;
+
+    if (!PyArg_ParseTuple(args, "i:_getfileinformation", &fd))
+        return NULL;
+
+    if (!_PyVerify_fd(fd)) {
+        PyErr_SetString(PyExc_ValueError,
+                        "received invalid file descriptor");
+        return NULL;
+    }
+
+    hFile = _get_osfhandle(fd);
+    if (hFile == INVALID_HANDLE_VALUE)
+        return win32_error("_getfileinformation", NULL);
+
+    if (!GetFileInformationByHandle(hFile, &info))
+        return win32_error("_getfileinformation", NULL);
+
+    return Py_BuildValue("iii", info.dwVolumeSerialNumber,
+                                info.nFileIndexHigh,
+                                info.nFileIndexLow);
+}
 #endif /* MS_WINDOWS */
 
 PyDoc_STRVAR(posix_mkdir__doc__,
@@ -7872,6 +7900,7 @@
 #ifdef MS_WINDOWS
     {"_getfullpathname",        posix__getfullpathname, METH_VARARGS, NULL},
     {"_getfinalpathname",       posix__getfinalpathname, METH_VARARGS, NULL},
+    {"_getfileinformation",     posix__getfileinformation, METH_VARARGS, NULL},
 #endif
 #ifdef HAVE_GETLOADAVG
     {"getloadavg",      posix_getloadavg, METH_NOARGS, posix_getloadavg__doc__},