diff --git a/Lib/ctypes/__init__.py b/Lib/ctypes/__init__.py
index d65ea7b..1283f28 100644
--- a/Lib/ctypes/__init__.py
+++ b/Lib/ctypes/__init__.py
@@ -485,7 +485,7 @@
 def cast(obj, typ):
     return _cast(obj, obj, typ)
 
-_string_at = CFUNCTYPE(py_object, c_void_p, c_int)(_string_at_addr)
+_string_at = PYFUNCTYPE(py_object, c_void_p, c_int)(_string_at_addr)
 def string_at(ptr, size=-1):
     """string_at(addr[, size]) -> string
 
@@ -497,7 +497,7 @@
 except ImportError:
     pass
 else:
-    _wstring_at = CFUNCTYPE(py_object, c_void_p, c_int)(_wstring_at_addr)
+    _wstring_at = PYFUNCTYPE(py_object, c_void_p, c_int)(_wstring_at_addr)
     def wstring_at(ptr, size=-1):
         """wstring_at(addr[, size]) -> string
 
diff --git a/Lib/ctypes/test/test_memfunctions.py b/Lib/ctypes/test/test_memfunctions.py
index 6a6411e..4bee77f 100644
--- a/Lib/ctypes/test/test_memfunctions.py
+++ b/Lib/ctypes/test/test_memfunctions.py
@@ -3,6 +3,16 @@
 from ctypes import *
 
 class MemFunctionsTest(unittest.TestCase):
+##    def test_overflow(self):
+##        # string_at and wstring_at must use the Python calling
+##        # convention (which acquires the GIL and checks the Python
+##        # error flag).  Provoke an error and catch it; see also issue
+##        # #3554: <http://bugs.python.org/issue3554>
+##        self.assertRaises((OverflowError, MemoryError, SystemError),
+##                          lambda: wstring_at(u"foo", sys.maxint - 1))
+##        self.assertRaises((OverflowError, MemoryError, SystemError),
+##                          lambda: string_at("foo", sys.maxint - 1))
+
     def test_memmove(self):
         # large buffers apparently increase the chance that the memory
         # is allocated in high address space.
diff --git a/Misc/NEWS b/Misc/NEWS
index 5ec4587..3823772 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -103,6 +103,12 @@
 
 - Removed the sunaudio module. Use sunau instead.
 
+- Issue #3554: ctypes.string_at and ctypes.wstring_at did call Python
+  api functions without holding the GIL, which could lead to a fatal
+  error when they failed.
+
+- Issue #799428: Fix Tkinter.Misc._nametowidget to unwrap Tcl command objects.
+
 - Removed "ast" function aliases from the parser module.
 
 - Issue #3313: Fixed a crash when a failed dlopen() call does not set