diff --git a/Lib/ctypes/test/test_loading.py b/Lib/ctypes/test/test_loading.py
index 28c83fd4a9d..ee34754d947 100644
--- a/Lib/ctypes/test/test_loading.py
+++ b/Lib/ctypes/test/test_loading.py
@@ -58,6 +58,33 @@ class LoaderTest(unittest.TestCase):
                 windll.LoadLibrary("coredll").GetModuleHandleW
                 WinDLL("coredll").GetModuleHandleW
 
+        def test_1703286_A(self):
+            from _ctypes import LoadLibrary, FreeLibrary
+            # On winXP 64-bit, advapi32 loads at an address that does
+            # NOT fit into a 32-bit integer.  FreeLibrary must be able
+            # to accept this address.
+
+            # These are tests for http://www.python.org/sf/1703286
+            handle = LoadLibrary("advapi32")
+            FreeLibrary(handle)
+
+        def test_1703286_B(self):
+            # Since on winXP 64-bit advapi32 loads like described
+            # above, the (arbitrarily selected) CloseEventLog function
+            # also has a high address.  'call_function' should accept
+            # addresses so large.
+            from _ctypes import call_function
+            advapi32 = windll.advapi32
+            # Calling CloseEventLog with a NULL argument should fail,
+            # but the call should not segfault or so.
+            self.failUnlessEqual(0, advapi32.CloseEventLog(None))
+            windll.kernel32.GetProcAddress.argtypes = c_void_p, c_char_p
+            windll.kernel32.GetProcAddress.restype = c_void_p
+            proc = windll.kernel32.GetProcAddress(advapi32._handle, "CloseEventLog")
+            self.failUnless(proc)
+            # This is the real test: call the function via 'call_function'
+            self.failUnlessEqual(0, call_function(proc, (None,)))
+
         def test_load_ordinal_functions(self):
             import _ctypes_test
             dll = WinDLL(_ctypes_test.__file__)
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index b7dda48a867..a8d4ce16017 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1128,10 +1128,10 @@ static char free_library_doc[] =
 Free the handle of an executable previously loaded by LoadLibrary.\n";
 static PyObject *free_library(PyObject *self, PyObject *args)
 {
-	HMODULE hMod;
-	if (!PyArg_ParseTuple(args, "i:FreeLibrary", &hMod))
+	void *hMod;
+	if (!PyArg_ParseTuple(args, PY_VOID_P_CODE ":FreeLibrary", &hMod))
 		return NULL;
-	if (!FreeLibrary(hMod))
+	if (!FreeLibrary((HMODULE)hMod))
 		return PyErr_SetFromWindowsErr(GetLastError());
 	Py_INCREF(Py_None);
 	return Py_None;
@@ -1250,11 +1250,11 @@ static PyObject *py_dl_open(PyObject *self, PyObject *args)
 
 static PyObject *py_dl_close(PyObject *self, PyObject *args)
 {
-	int handle;
+	void *handle;
 
-	if (!PyArg_ParseTuple(args, "i:dlclose", &handle))
+	if (!PyArg_ParseTuple(args, PY_VOID_P_CODE ":dlclose", &handle))
 		return NULL;
-	if (dlclose((void*)handle)) {
+	if (dlclose(handle)) {
 		PyErr_SetString(PyExc_OSError,
 				       ctypes_dlerror());
 		return NULL;
@@ -1266,10 +1266,10 @@ static PyObject *py_dl_close(PyObject *self, PyObject *args)
 static PyObject *py_dl_sym(PyObject *self, PyObject *args)
 {
 	char *name;
-	int handle;
+	void *handle;
 	void *ptr;
 
-	if (!PyArg_ParseTuple(args, "is:dlsym", &handle, &name))
+	if (!PyArg_ParseTuple(args, PY_VOID_P_CODE "s:dlsym", &handle, &name))
 		return NULL;
 	ptr = ctypes_dlsym((void*)handle, name);
 	if (!ptr) {
@@ -1277,7 +1277,7 @@ static PyObject *py_dl_sym(PyObject *self, PyObject *args)
 				       ctypes_dlerror());
 		return NULL;
 	}
-	return Py_BuildValue("i", ptr);
+	return PyLong_FromVoidPtr(ptr);
 }
 #endif
 
@@ -1289,12 +1289,12 @@ static PyObject *py_dl_sym(PyObject *self, PyObject *args)
 static PyObject *
 call_function(PyObject *self, PyObject *args)
 {
-	int func;
+	void *func;
 	PyObject *arguments;
 	PyObject *result;
 
 	if (!PyArg_ParseTuple(args,
-			      "iO!",
+			      PY_VOID_P_CODE "O!",
 			      &func,
 			      &PyTuple_Type, &arguments))
 		return NULL;
@@ -1320,12 +1320,12 @@ call_function(PyObject *self, PyObject *args)
 static PyObject *
 call_cdeclfunction(PyObject *self, PyObject *args)
 {
-	int func;
+	void *func;
 	PyObject *arguments;
 	PyObject *result;
 
 	if (!PyArg_ParseTuple(args,
-			      "iO!",
+			      PY_VOID_P_CODE "O!",
 			      &func,
 			      &PyTuple_Type, &arguments))
 		return NULL;
diff --git a/Modules/_ctypes/ctypes.h b/Modules/_ctypes/ctypes.h
index 0af78510208..5fb603075d3 100644
--- a/Modules/_ctypes/ctypes.h
+++ b/Modules/_ctypes/ctypes.h
@@ -23,6 +23,12 @@ typedef int Py_ssize_t;
 #define PY_LONG_LONG LONG_LONG
 #endif
 
+#if SIZEOF_VOID_P == SIZEOF_LONG
+#define PY_VOID_P_CODE "k"
+#elif defined(HAVE_LONG_LONG) && (SIZEOF_VOID_P == SIZEOF_LONG_LONG)
+#define PY_VOID_P_CODE "K"
+#endif
+
 typedef struct tagPyCArgObject PyCArgObject;
 typedef struct tagCDataObject CDataObject;
 typedef PyObject *(* GETFUNC)(void *, unsigned size);