--- rest25/library/ctypes.rst	2008-12-19 16:58:07.000000000 +0900
+++ rest262/library/ctypes.rst	2009-04-05 05:02:09.000000000 +0900
@@ -1,86 +1,86 @@
 
 :mod:`ctypes` --- A foreign function library for Python.
 ========================================================
 
 .. module:: ctypes
    :synopsis: A foreign function library for Python.
 .. moduleauthor:: Thomas Heller <theller@python.net>
 
 
 .. versionadded:: 2.5
 
 ``ctypes`` is a foreign function library for Python.  It provides C compatible
-data types, and allows to call functions in dlls/shared libraries.  It can be
+data types, and allows calling functions in DLLs or shared libraries.  It can be
 used to wrap these libraries in pure Python.
 
 
 .. _ctypes-ctypes-tutorial:
 
 ctypes tutorial
 ---------------
 
-Note: The code samples in this tutorial uses ``doctest`` to make sure that they
+Note: The code samples in this tutorial use ``doctest`` to make sure that they
 actually work.  Since some code samples behave differently under Linux, Windows,
 or Mac OS X, they contain doctest directives in comments.
 
-Note: Quite some code samples references the ctypes :class:`c_int` type. This
-type is an alias to the :class:`c_long` type on 32-bit systems.  So, you should
-not be confused if :class:`c_long` is printed if you would expect :class:`c_int`
-- they are actually the same type.
+Note: Some code samples reference the ctypes :class:`c_int` type. This type is
+an alias for the :class:`c_long` type on 32-bit systems.  So, you should not be
+confused if :class:`c_long` is printed if you would expect :class:`c_int` ---
+they are actually the same type.
 
 
 .. _ctypes-loading-dynamic-link-libraries:
 
 Loading dynamic link libraries
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-``ctypes`` exports the *cdll*, and on Windows also *windll* and *oledll* objects
-to load dynamic link libraries.
+``ctypes`` exports the *cdll*, and on Windows *windll* and *oledll*
+objects, for loading dynamic link libraries.
 
 You load libraries by accessing them as attributes of these objects. *cdll*
 loads libraries which export functions using the standard ``cdecl`` calling
 convention, while *windll* libraries call functions using the ``stdcall``
 calling convention. *oledll* also uses the ``stdcall`` calling convention, and
 assumes the functions return a Windows :class:`HRESULT` error code. The error
-code is used to automatically raise :class:`WindowsError` Python exceptions when
+code is used to automatically raise a :class:`WindowsError` exception when
 the function call fails.
 
-Here are some examples for Windows, note that ``msvcrt`` is the MS standard C
+Here are some examples for Windows. Note that ``msvcrt`` is the MS standard C
 library containing most standard C functions, and uses the cdecl calling
 convention::
 
    >>> from ctypes import *
    >>> print windll.kernel32 # doctest: +WINDOWS
    <WinDLL 'kernel32', handle ... at ...>
    >>> print cdll.msvcrt # doctest: +WINDOWS
    <CDLL 'msvcrt', handle ... at ...>
    >>> libc = cdll.msvcrt # doctest: +WINDOWS
    >>>
 
-Windows appends the usual '.dll' file suffix automatically.
+Windows appends the usual ``.dll`` file suffix automatically.
 
 On Linux, it is required to specify the filename *including* the extension to
-load a library, so attribute access does not work. Either the
+load a library, so attribute access can not be used to load libraries. Either the
 :meth:`LoadLibrary` method of the dll loaders should be used, or you should load
 the library by creating an instance of CDLL by calling the constructor::
 
    >>> cdll.LoadLibrary("libc.so.6") # doctest: +LINUX
    <CDLL 'libc.so.6', handle ... at ...>
    >>> libc = CDLL("libc.so.6")     # doctest: +LINUX
    >>> libc                         # doctest: +LINUX
    <CDLL 'libc.so.6', handle ... at ...>
    >>>
 
-.. % XXX Add section for Mac OS X.
+.. XXX Add section for Mac OS X.
 
 
 .. _ctypes-accessing-functions-from-loaded-dlls:
 
 Accessing functions from loaded dlls
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Functions are accessed as attributes of dll objects::
 
    >>> from ctypes import *
    >>> libc.printf
    <_FuncPtr object at 0x...>
@@ -100,25 +100,25 @@
 appended to the name. The win32 ``GetModuleHandle`` function, which returns a
 *module handle* for a given module name, has the following C prototype, and a
 macro is used to expose one of them as ``GetModuleHandle`` depending on whether
 UNICODE is defined or not::
 
    /* ANSI version */
    HMODULE GetModuleHandleA(LPCSTR lpModuleName);
    /* UNICODE version */
    HMODULE GetModuleHandleW(LPCWSTR lpModuleName);
 
 *windll* does not try to select one of them by magic, you must access the
 version you need by specifying ``GetModuleHandleA`` or ``GetModuleHandleW``
-explicitely, and then call it with normal strings or unicode strings
+explicitly, and then call it with strings or unicode strings
 respectively.
 
 Sometimes, dlls export functions with names which aren't valid Python
 identifiers, like ``"??2@YAPAXI@Z"``. In this case you have to use ``getattr``
 to retrieve the function::
 
    >>> getattr(cdll.msvcrt, "??2@YAPAXI@Z") # doctest: +WINDOWS
    <_FuncPtr object at 0x...>
    >>>
 
 On Windows, some dlls export functions not by name but by ordinal. These
 functions can be accessed by indexing the dll object with the ordinal number::
@@ -240,24 +240,26 @@
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_ulong`     | ``unsigned long``              | int/long                   |
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_longlong`  | ``__int64`` or ``long long``   | int/long                   |
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_ulonglong` | ``unsigned __int64`` or        | int/long                   |
    |                      | ``unsigned long long``         |                            |
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_float`     | ``float``                      | float                      |
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_double`    | ``double``                     | float                      |
    +----------------------+--------------------------------+----------------------------+
+   | :class:`c_longdouble`| ``long double``                | float                      |
+   +----------------------+--------------------------------+----------------------------+
    | :class:`c_char_p`    | ``char *`` (NUL terminated)    | string or ``None``         |
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_wchar_p`   | ``wchar_t *`` (NUL terminated) | unicode or ``None``        |
    +----------------------+--------------------------------+----------------------------+
    | :class:`c_void_p`    | ``void *``                     | int/long or ``None``       |
    +----------------------+--------------------------------+----------------------------+
 
 
 All these types can be created by calling them with an optional initializer of
 the correct type and value::
 
    >>> c_int()
@@ -291,40 +293,40 @@
    c_char_p('Hello, World')
    >>> c_s.value = "Hi, there"
    >>> print c_s
    c_char_p('Hi, there')
    >>> print s                 # first string is unchanged
    Hello, World
    >>>
 
 You should be careful, however, not to pass them to functions expecting pointers
 to mutable memory. If you need mutable memory blocks, ctypes has a
 ``create_string_buffer`` function which creates these in various ways.  The
 current memory block contents can be accessed (or changed) with the ``raw``
-property, if you want to access it as NUL terminated string, use the ``string``
+property; if you want to access it as NUL terminated string, use the ``value``
 property::
 
    >>> from ctypes import *
    >>> p = create_string_buffer(3)      # create a 3 byte buffer, initialized to NUL bytes
    >>> print sizeof(p), repr(p.raw)
    3 '\x00\x00\x00'
    >>> p = create_string_buffer("Hello")      # create a buffer containing a NUL terminated string
    >>> print sizeof(p), repr(p.raw)
    6 'Hello\x00'
    >>> print repr(p.value)
    'Hello'
    >>> p = create_string_buffer("Hello", 10)  # create a 10 byte buffer
    >>> print sizeof(p), repr(p.raw)
    10 'Hello\x00\x00\x00\x00\x00'
-   >>> p.value = "Hi"      
+   >>> p.value = "Hi"
    >>> print sizeof(p), repr(p.raw)
    10 'Hi\x00lo\x00\x00\x00\x00\x00'
    >>>
 
 The ``create_string_buffer`` function replaces the ``c_buffer`` function (which
 is still available as an alias), as well as the ``c_string`` function from
 earlier ctypes releases.  To create a mutable memory block containing unicode
 characters of the C type ``wchar_t`` use the ``create_unicode_buffer`` function.
 
 
 .. _ctypes-calling-functions-continued:
 
@@ -374,25 +376,25 @@
    >>> class Bottles(object):
    ...     def __init__(self, number):
    ...         self._as_parameter_ = number
    ...
    >>> bottles = Bottles(42)
    >>> printf("%d bottles of beer\n", bottles)
    42 bottles of beer
    19
    >>>
 
 If you don't want to store the instance's data in the :attr:`_as_parameter_`
 instance variable, you could define a ``property`` which makes the data
-avaiblable.
+available.
 
 
 .. _ctypes-specifying-required-argument-types:
 
 Specifying the required argument types (function prototypes)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 It is possible to specify the required argument types of functions exported from
 DLLs by setting the :attr:`argtypes` attribute.
 
 :attr:`argtypes` must be a sequence of C data types (the ``printf`` function is
 probably not a good example here, because it takes a variable number and
@@ -413,27 +415,27 @@
      File "<stdin>", line 1, in ?
    ArgumentError: argument 2: exceptions.TypeError: wrong type
    >>> printf("%s %d %f", "X", 2, 3)
    X 2 3.00000012
    12
    >>>
 
 If you have defined your own classes which you pass to function calls, you have
 to implement a :meth:`from_param` class method for them to be able to use them
 in the :attr:`argtypes` sequence. The :meth:`from_param` class method receives
 the Python object passed to the function call, it should do a typecheck or
 whatever is needed to make sure this object is acceptable, and then return the
-object itself, it's :attr:`_as_parameter_` attribute, or whatever you want to
+object itself, its :attr:`_as_parameter_` attribute, or whatever you want to
 pass as the C function argument in this case. Again, the result should be an
-integer, string, unicode, a ``ctypes`` instance, or something having the
+integer, string, unicode, a ``ctypes`` instance, or an object with an
 :attr:`_as_parameter_` attribute.
 
 
 .. _ctypes-return-types:
 
 Return types
 ^^^^^^^^^^^^
 
 By default functions are assumed to return the C ``int`` type.  Other return
 types can be specified by setting the :attr:`restype` attribute of the function
 object.
 
@@ -575,41 +577,41 @@
    >>> rc = RECT(point)
    >>> print rc.upperleft.x, rc.upperleft.y
    0 5
    >>> print rc.lowerright.x, rc.lowerright.y
    0 0
    >>>
 
 Nested structures can also be initialized in the constructor in several ways::
 
    >>> r = RECT(POINT(1, 2), POINT(3, 4))
    >>> r = RECT((1, 2), (3, 4))
 
-Fields descriptors can be retrieved from the *class*, they are useful for
-debugging because they can provide useful information::
+Field :term:`descriptor`\s can be retrieved from the *class*, they are useful
+for debugging because they can provide useful information::
 
    >>> print POINT.x
    <Field type=c_long, ofs=0, size=4>
    >>> print POINT.y
    <Field type=c_long, ofs=4, size=4>
    >>>
 
 
 .. _ctypes-structureunion-alignment-byte-order:
 
 Structure/union alignment and byte order
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 By default, Structure and Union fields are aligned in the same way the C
-compiler does it. It is possible to override this behaviour be specifying a
+compiler does it. It is possible to override this behavior be specifying a
 :attr:`_pack_` class attribute in the subclass definition. This must be set to a
 positive integer and specifies the maximum alignment for the fields. This is
 what ``#pragma pack(n)`` also does in MSVC.
 
 ``ctypes`` uses the native byte order for Structures and Unions.  To build
 structures with non-native byte order, you can use one of the
 BigEndianStructure, LittleEndianStructure, BigEndianUnion, and LittleEndianUnion
 base classes.  These classes cannot contain pointer fields.
 
 
 .. _ctypes-bit-fields-in-structures-unions:
 
@@ -634,25 +636,25 @@
 .. _ctypes-arrays:
 
 Arrays
 ^^^^^^
 
 Arrays are sequences, containing a fixed number of instances of the same type.
 
 The recommended way to create array types is by multiplying a data type with a
 positive integer::
 
    TenPointsArrayType = POINT * 10
 
-Here is an example of an somewhat artifical data type, a structure containing 4
+Here is an example of an somewhat artificial data type, a structure containing 4
 POINTs among other stuff::
 
    >>> from ctypes import *
    >>> class POINT(Structure):
    ...    _fields_ = ("x", c_int), ("y", c_int)
    ...
    >>> class MyStruct(Structure):
    ...    _fields_ = [("a", c_int),
    ...                ("b", c_float),
    ...                ("point_array", POINT * 4)]
    >>>
    >>> print len(MyStruct().point_array)
@@ -710,24 +712,26 @@
    False
    >>>
 
 Assigning another :class:`c_int` instance to the pointer's contents attribute
 would cause the pointer to point to the memory location where this is stored::
 
    >>> i = c_int(99)
    >>> pi.contents = i
    >>> pi.contents
    c_long(99)
    >>>
 
+.. XXX Document dereferencing pointers, and that it is preferred over the .contents attribute.
+
 Pointer instances can also be indexed with integers::
 
    >>> pi[0]
    99
    >>>
 
 Assigning to an integer index changes the pointed to value::
 
    >>> print i
    c_long(99)
    >>> pi[0] = 22
    >>> print i
@@ -756,25 +760,25 @@
    <ctypes.LP_c_long object at 0x...>
    >>>
 
 Calling the pointer type without an argument creates a ``NULL`` pointer.
 ``NULL`` pointers have a ``False`` boolean value::
 
    >>> null_ptr = POINTER(c_int)()
    >>> print bool(null_ptr)
    False
    >>>
 
 ``ctypes`` checks for ``NULL`` when dereferencing pointers (but dereferencing
-non-\ ``NULL`` pointers would crash Python)::
+invalid non-\ ``NULL`` pointers would crash Python)::
 
    >>> null_ptr[0]
    Traceback (most recent call last):
        ....
    ValueError: NULL pointer access
    >>>
 
    >>> null_ptr[0] = 1234
    Traceback (most recent call last):
        ....
    ValueError: NULL pointer access
    >>>
@@ -802,27 +806,27 @@
    ...     print bar.values[i]
    ...
    1
    2
    3
    >>>
 
 To set a POINTER type field to ``NULL``, you can assign ``None``::
 
    >>> bar.values = None
    >>>
 
-XXX list other conversions...
+.. XXX list other conversions...
 
-Sometimes you have instances of incompatible types.  In ``C``, you can cast one
+Sometimes you have instances of incompatible types.  In C, you can cast one
 type into another type.  ``ctypes`` provides a ``cast`` function which can be
 used in the same way.  The ``Bar`` structure defined above accepts
 ``POINTER(c_int)`` pointers or :class:`c_int` arrays for its ``values`` field,
 but not instances of other types::
 
    >>> bar.values = (c_byte * 4)()
    Traceback (most recent call last):
      File "<stdin>", line 1, in ?
    TypeError: incompatible types, c_byte_Array_4 instance instead of LP_c_long instance
    >>>
 
 For these cases, the ``cast`` function is handy.
@@ -895,25 +899,25 @@
    >>> c1 = cell()
    >>> c1.name = "foo"
    >>> c2 = cell()
    >>> c2.name = "bar"
    >>> c1.next = pointer(c2)
    >>> c2.next = pointer(c1)
    >>> p = c1
    >>> for i in range(8):
    ...     print p.name,
    ...     p = p.next[0]
    ...
    foo bar foo bar foo bar foo bar
-   >>>    
+   >>>
 
 
 .. _ctypes-callback-functions:
 
 Callback functions
 ^^^^^^^^^^^^^^^^^^
 
 ``ctypes`` allows to create C callable function pointers from Python callables.
 These are sometimes called *callback functions*.
 
 First, you must create a class for the callback function, the class knows the
 calling convention, the return type, and the number and types of arguments this
@@ -1042,50 +1046,50 @@
 
    >>> qsort(ia, len(ia), sizeof(c_int), CMPFUNC(py_cmp_func)) # doctest: +LINUX
    py_cmp_func 5 1
    py_cmp_func 33 99
    py_cmp_func 7 33
    py_cmp_func 1 7
    py_cmp_func 5 7
    >>>
 
 It is quite interesting to see that the Windows :func:`qsort` function needs
 more comparisons than the linux version!
 
-As we can easily check, our array sorted now::
+As we can easily check, our array is sorted now::
 
    >>> for i in ia: print i,
    ...
    1 5 7 33 99
    >>>
 
 **Important note for callback functions:**
 
 Make sure you keep references to CFUNCTYPE objects as long as they are used from
 C code. ``ctypes`` doesn't, and if you don't, they may be garbage collected,
 crashing your program when a callback is made.
 
 
 .. _ctypes-accessing-values-exported-from-dlls:
 
 Accessing values exported from dlls
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Sometimes, a dll not only exports functions, it also exports variables. An
+Some shared libraries not only export functions, they also export variables. An
 example in the Python library itself is the ``Py_OptimizeFlag``, an integer set
 to 0, 1, or 2, depending on the :option:`-O` or :option:`-OO` flag given on
 startup.
 
 ``ctypes`` can access values like this with the :meth:`in_dll` class methods of
-the type.  *pythonapi* ìs a predefined symbol giving access to the Python C
+the type.  *pythonapi* is a predefined symbol giving access to the Python C
 api::
 
    >>> opt_flag = c_int.in_dll(pythonapi, "Py_OptimizeFlag")
    >>> print opt_flag
    c_long(0)
    >>>
 
 If the interpreter would have been started with :option:`-O`, the sample would
 have printed ``c_long(1)``, or ``c_long(2)`` if :option:`-OO` would have been
 specified.
 
 An extended example which also demonstrates the use of pointers accesses the
@@ -1125,25 +1129,25 @@
    >>> for item in table:
    ...    print item.name, item.size
    ...    if item.name is None:
    ...        break
    ...
    __hello__ 104
    __phello__ -104
    __phello__.spam 104
    None 0
    >>>
 
 The fact that standard Python has a frozen module and a frozen package
-(indicated by the negative size member) is not wellknown, it is only used for
+(indicated by the negative size member) is not well known, it is only used for
 testing. Try it out with ``import __hello__`` for example.
 
 
 .. _ctypes-surprises:
 
 Surprises
 ^^^^^^^^^
 
 There are some edges in ``ctypes`` where you may be expect something else than
 what actually happens.
 
 Consider the following example::
@@ -1158,56 +1162,56 @@
    >>> p1 = POINT(1, 2)
    >>> p2 = POINT(3, 4)
    >>> rc = RECT(p1, p2)
    >>> print rc.a.x, rc.a.y, rc.b.x, rc.b.y
    1 2 3 4
    >>> # now swap the two points
    >>> rc.a, rc.b = rc.b, rc.a
    >>> print rc.a.x, rc.a.y, rc.b.x, rc.b.y
    3 4 3 4
    >>>
 
 Hm. We certainly expected the last statement to print ``3 4 1 2``. What
-happended? Here are the steps of the ``rc.a, rc.b = rc.b, rc.a`` line above::
+happened? Here are the steps of the ``rc.a, rc.b = rc.b, rc.a`` line above::
 
    >>> temp0, temp1 = rc.b, rc.a
    >>> rc.a = temp0
    >>> rc.b = temp1
    >>>
 
 Note that ``temp0`` and ``temp1`` are objects still using the internal buffer of
 the ``rc`` object above. So executing ``rc.a = temp0`` copies the buffer
 contents of ``temp0`` into ``rc`` 's buffer.  This, in turn, changes the
 contents of ``temp1``. So, the last assignment ``rc.b = temp1``, doesn't have
 the expected effect.
 
-Keep in mind that retrieving subobjects from Structure, Unions, and Arrays
-doesn't *copy* the subobject, instead it retrieves a wrapper object accessing
+Keep in mind that retrieving sub-objects from Structure, Unions, and Arrays
+doesn't *copy* the sub-object, instead it retrieves a wrapper object accessing
 the root-object's underlying buffer.
 
 Another example that may behave different from what one would expect is this::
 
    >>> s = c_char_p()
    >>> s.value = "abc def ghi"
    >>> s.value
    'abc def ghi'
    >>> s.value is s.value
    False
    >>>
 
 Why is it printing ``False``?  ctypes instances are objects containing a memory
-block plus some descriptors accessing the contents of the memory.  Storing a
-Python object in the memory block does not store the object itself, instead the
-``contents`` of the object is stored. Accessing the contents again constructs a
-new Python each time!
+block plus some :term:`descriptor`\s accessing the contents of the memory.
+Storing a Python object in the memory block does not store the object itself,
+instead the ``contents`` of the object is stored.  Accessing the contents again
+constructs a new Python object each time!
 
 
 .. _ctypes-variable-sized-data-types:
 
 Variable-sized data types
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 ``ctypes`` provides some support for variable-sized arrays and structures (this
 was added in version 0.9.9.7).
 
 The ``resize`` function can be used to resize the memory buffer of an existing
 ctypes object.  The function takes the object as first argument, and the
@@ -1237,87 +1241,73 @@
    [0, 0, 0, 0]
    >>> short_array[7]
    Traceback (most recent call last):
        ...
    IndexError: invalid index
    >>>
 
 Another way to use variable-sized data types with ``ctypes`` is to use the
 dynamic nature of Python, and (re-)define the data type after the required size
 is already known, on a case by case basis.
 
 
-.. _ctypes-bugs-todo-non-implemented-things:
-
-Bugs, ToDo and non-implemented things
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Enumeration types are not implemented. You can do it easily yourself, using
-:class:`c_int` as the base class.
-
-``long double`` is not implemented.
-
-.. % Local Variables:
-.. % compile-command: "make.bat"
-.. % End:
-
-
 .. _ctypes-ctypes-reference:
 
 ctypes reference
 ----------------
 
 
 .. _ctypes-finding-shared-libraries:
 
 Finding shared libraries
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
 When programming in a compiled language, shared libraries are accessed when
 compiling/linking a program, and when the program is run.
 
 The purpose of the ``find_library`` function is to locate a library in a way
 similar to what the compiler does (on platforms with several versions of a
 shared library the most recent should be loaded), while the ctypes library
 loaders act like when a program is run, and call the runtime loader directly.
 
 The ``ctypes.util`` module provides a function which can help to determine the
 library to load.
 
 
 .. data:: find_library(name)
+   :module: ctypes.util
    :noindex:
 
    Try to find a library and return a pathname.  *name* is the library name without
    any prefix like *lib*, suffix like ``.so``, ``.dylib`` or version number (this
    is the form used for the posix linker option :option:`-l`).  If no library can
    be found, returns ``None``.
 
-The exact functionality is system dependend.
+The exact functionality is system dependent.
 
 On Linux, ``find_library`` tries to run external programs (/sbin/ldconfig, gcc,
 and objdump) to find the library file.  It returns the filename of the library
-file.  Here are sone examples::
+file.  Here are some examples::
 
    >>> from ctypes.util import find_library
    >>> find_library("m")
    'libm.so.6'
    >>> find_library("c")
    'libc.so.6'
    >>> find_library("bz2")
    'libbz2.so.1.0'
    >>>
 
 On OS X, ``find_library`` tries several predefined naming schemes and paths to
-locate the library, and returns a full pathname if successfull::
+locate the library, and returns a full pathname if successful::
 
    >>> from ctypes.util import find_library
    >>> find_library("c")
    '/usr/lib/libc.dylib'
    >>> find_library("m")
    '/usr/lib/libm.dylib'
    >>> find_library("bz2")
    '/usr/lib/libbz2.dylib'
    >>> find_library("AGL")
    '/System/Library/Frameworks/AGL.framework/AGL'
    >>>
 
@@ -1330,134 +1320,154 @@
 module instead of using ``find_library`` to locate the library at runtime.
 
 
 .. _ctypes-loading-shared-libraries:
 
 Loading shared libraries
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
 There are several ways to loaded shared libraries into the Python process.  One
 way is to instantiate one of the following classes:
 
 
-.. class:: CDLL(name, mode=DEFAULT_MODE, handle=None)
+.. class:: CDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False)
 
    Instances of this class represent loaded shared libraries. Functions in these
    libraries use the standard C calling convention, and are assumed to return
    ``int``.
 
 
-.. class:: OleDLL(name, mode=DEFAULT_MODE, handle=None)
+.. class:: OleDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False)
 
    Windows only: Instances of this class represent loaded shared libraries,
    functions in these libraries use the ``stdcall`` calling convention, and are
    assumed to return the windows specific :class:`HRESULT` code.  :class:`HRESULT`
    values contain information specifying whether the function call failed or
    succeeded, together with additional error code.  If the return value signals a
    failure, an :class:`WindowsError` is automatically raised.
 
 
-.. class:: WinDLL(name, mode=DEFAULT_MODE, handle=None)
+.. class:: WinDLL(name, mode=DEFAULT_MODE, handle=None, use_errno=False, use_last_error=False)
 
    Windows only: Instances of this class represent loaded shared libraries,
    functions in these libraries use the ``stdcall`` calling convention, and are
    assumed to return ``int`` by default.
 
    On Windows CE only the standard calling convention is used, for convenience the
    :class:`WinDLL` and :class:`OleDLL` use the standard calling convention on this
    platform.
 
-The Python GIL is released before calling any function exported by these
-libraries, and reaquired afterwards.
+The Python :term:`global interpreter lock` is released before calling any
+function exported by these libraries, and reacquired afterwards.
 
 
 .. class:: PyDLL(name, mode=DEFAULT_MODE, handle=None)
 
    Instances of this class behave like :class:`CDLL` instances, except that the
    Python GIL is *not* released during the function call, and after the function
    execution the Python error flag is checked. If the error flag is set, a Python
    exception is raised.
 
    Thus, this is only useful to call Python C api functions directly.
 
 All these classes can be instantiated by calling them with at least one
 argument, the pathname of the shared library.  If you have an existing handle to
-an already loaded shard library, it can be passed as the ``handle`` named
+an already loaded shared library, it can be passed as the ``handle`` named
 parameter, otherwise the underlying platforms ``dlopen`` or :meth:`LoadLibrary`
 function is used to load the library into the process, and to get a handle to
 it.
 
 The *mode* parameter can be used to specify how the library is loaded.  For
 details, consult the ``dlopen(3)`` manpage, on Windows, *mode* is ignored.
 
+The *use_errno* parameter, when set to True, enables a ctypes mechanism that
+allows to access the system :data:`errno` error number in a safe way.
+:mod:`ctypes` maintains a thread-local copy of the systems :data:`errno`
+variable; if you call foreign functions created with ``use_errno=True`` then the
+:data:`errno` value before the function call is swapped with the ctypes private
+copy, the same happens immediately after the function call.
+
+The function :func:`ctypes.get_errno` returns the value of the ctypes private
+copy, and the function :func:`ctypes.set_errno` changes the ctypes private copy
+to a new value and returns the former value.
+
+The *use_last_error* parameter, when set to True, enables the same mechanism for
+the Windows error code which is managed by the :func:`GetLastError` and
+:func:`SetLastError` Windows API functions; :func:`ctypes.get_last_error` and
+:func:`ctypes.set_last_error` are used to request and change the ctypes private
+copy of the windows error code.
+
+.. versionadded:: 2.6
+   The ``use_last_error`` and ``use_errno`` optional parameters
+   were added.
 
 .. data:: RTLD_GLOBAL
    :noindex:
 
    Flag to use as *mode* parameter.  On platforms where this flag is not available,
    it is defined as the integer zero.
 
 
 .. data:: RTLD_LOCAL
    :noindex:
 
    Flag to use as *mode* parameter.  On platforms where this is not available, it
    is the same as *RTLD_GLOBAL*.
 
 
 .. data:: DEFAULT_MODE
    :noindex:
 
    The default mode which is used to load shared libraries.  On OSX 10.3, this is
    *RTLD_GLOBAL*, otherwise it is the same as *RTLD_LOCAL*.
 
 Instances of these classes have no public methods, however :meth:`__getattr__`
-and :meth:`__getitem__` have special behaviour: functions exported by the shared
+and :meth:`__getitem__` have special behavior: functions exported by the shared
 library can be accessed as attributes of by index.  Please note that both
 :meth:`__getattr__` and :meth:`__getitem__` cache their result, so calling them
 repeatedly returns the same object each time.
 
 The following public attributes are available, their name starts with an
 underscore to not clash with exported function names:
 
 
 .. attribute:: PyDLL._handle
 
    The system handle used to access the library.
 
 
 .. attribute:: PyDLL._name
 
-   The name of the library passed in the contructor.
+   The name of the library passed in the constructor.
 
 Shared libraries can also be loaded by using one of the prefabricated objects,
 which are instances of the :class:`LibraryLoader` class, either by calling the
 :meth:`LoadLibrary` method, or by retrieving the library as attribute of the
 loader instance.
 
 
 .. class:: LibraryLoader(dlltype)
 
    Class which loads shared libraries.  ``dlltype`` should be one of the
    :class:`CDLL`, :class:`PyDLL`, :class:`WinDLL`, or :class:`OleDLL` types.
 
-   :meth:`__getattr__` has special behaviour: It allows to load a shared library by
+   :meth:`__getattr__` has special behavior: It allows to load a shared library by
    accessing it as attribute of a library loader instance.  The result is cached,
    so repeated attribute accesses return the same library each time.
 
 
-.. method:: LibraryLoader.LoadLibrary(name)
+   .. method:: LoadLibrary(name)
 
-   Load a shared library into the process and return it.  This method always
-   returns a new instance of the library.
+      Load a shared library into the process and return it.  This method always
+      returns a new instance of the library.
 
 These prefabricated library loaders are available:
 
 
 .. data:: cdll
    :noindex:
 
    Creates :class:`CDLL` instances.
 
 
 .. data:: windll
    :noindex:
@@ -1496,300 +1506,313 @@
 
 As explained in the previous section, foreign functions can be accessed as
 attributes of loaded shared libraries.  The function objects created in this way
 by default accept any number of arguments, accept any ctypes data instances as
 arguments, and return the default result type specified by the library loader.
 They are instances of a private class:
 
 
 .. class:: _FuncPtr
 
    Base class for C callable foreign functions.
 
-Instances of foreign functions are also C compatible data types; they represent
-C function pointers.
+   Instances of foreign functions are also C compatible data types; they
+   represent C function pointers.
 
-This behaviour can be customized by assigning to special attributes of the
-foreign function object.
+   This behavior can be customized by assigning to special attributes of the
+   foreign function object.
 
 
-.. attribute:: _FuncPtr.restype
+   .. attribute:: restype
 
-   Assign a ctypes type to specify the result type of the foreign function.  Use
-   ``None`` for ``void`` a function not returning anything.
+      Assign a ctypes type to specify the result type of the foreign function.
+      Use ``None`` for ``void`` a function not returning anything.
 
-   It is possible to assign a callable Python object that is not a ctypes type, in
-   this case the function is assumed to return a C ``int``, and the callable will
-   be called with this integer, allowing to do further processing or error
-   checking.  Using this is deprecated, for more flexible postprocessing or error
-   checking use a ctypes data type as :attr:`restype` and assign a callable to the
-   :attr:`errcheck` attribute.
+      It is possible to assign a callable Python object that is not a ctypes
+      type, in this case the function is assumed to return a C ``int``, and the
+      callable will be called with this integer, allowing to do further
+      processing or error checking.  Using this is deprecated, for more flexible
+      post processing or error checking use a ctypes data type as
+      :attr:`restype` and assign a callable to the :attr:`errcheck` attribute.
 
 
-.. attribute:: _FuncPtr.argtypes
+   .. attribute:: argtypes
 
-   Assign a tuple of ctypes types to specify the argument types that the function
-   accepts.  Functions using the ``stdcall`` calling convention can only be called
-   with the same number of arguments as the length of this tuple; functions using
-   the C calling convention accept additional, unspecified arguments as well.
+      Assign a tuple of ctypes types to specify the argument types that the
+      function accepts.  Functions using the ``stdcall`` calling convention can
+      only be called with the same number of arguments as the length of this
+      tuple; functions using the C calling convention accept additional,
+      unspecified arguments as well.
 
-   When a foreign function is called, each actual argument is passed to the
-   :meth:`from_param` class method of the items in the :attr:`argtypes` tuple, this
-   method allows to adapt the actual argument to an object that the foreign
-   function accepts.  For example, a :class:`c_char_p` item in the :attr:`argtypes`
-   tuple will convert a unicode string passed as argument into an byte string using
-   ctypes conversion rules.
+      When a foreign function is called, each actual argument is passed to the
+      :meth:`from_param` class method of the items in the :attr:`argtypes`
+      tuple, this method allows to adapt the actual argument to an object that
+      the foreign function accepts.  For example, a :class:`c_char_p` item in
+      the :attr:`argtypes` tuple will convert a unicode string passed as
+      argument into an byte string using ctypes conversion rules.
 
-   New: It is now possible to put items in argtypes which are not ctypes types, but
-   each item must have a :meth:`from_param` method which returns a value usable as
-   argument (integer, string, ctypes instance).  This allows to define adapters
-   that can adapt custom objects as function parameters.
+      New: It is now possible to put items in argtypes which are not ctypes
+      types, but each item must have a :meth:`from_param` method which returns a
+      value usable as argument (integer, string, ctypes instance).  This allows
+      to define adapters that can adapt custom objects as function parameters.
 
 
-.. attribute:: _FuncPtr.errcheck
+   .. attribute:: errcheck
 
-   Assign a Python function or another callable to this attribute. The callable
-   will be called with three or more arguments:
+      Assign a Python function or another callable to this attribute. The
+      callable will be called with three or more arguments:
 
+      .. function:: callable(result, func, arguments)
+         :noindex:
 
-.. function:: callable(result, func, arguments)
-   :noindex:
-
-   ``result`` is what the foreign function returns, as specified by the
-   :attr:`restype` attribute.
+         ``result`` is what the foreign function returns, as specified
+         by the :attr:`restype` attribute.
 
-   ``func`` is the foreign function object itself, this allows to reuse the same
-   callable object to check or postprocess the results of several functions.
+         ``func`` is the foreign function object itself, this allows
+         to reuse the same callable object to check or post process
+         the results of several functions.
 
-   ``arguments`` is a tuple containing the parameters originally passed to the
-   function call, this allows to specialize the behaviour on the arguments used.
+         ``arguments`` is a tuple containing the parameters originally
+         passed to the function call, this allows to specialize the
+         behavior on the arguments used.
 
-   The object that this function returns will be returned from the foreign function
-   call, but it can also check the result value and raise an exception if the
-   foreign function call failed.
+      The object that this function returns will be returned from the
+      foreign function call, but it can also check the result value
+      and raise an exception if the foreign function call failed.
 
 
 .. exception:: ArgumentError()
 
    This exception is raised when a foreign function call cannot convert one of the
    passed arguments.
 
 
 .. _ctypes-function-prototypes:
 
 Function prototypes
 ^^^^^^^^^^^^^^^^^^^
 
 Foreign functions can also be created by instantiating function prototypes.
 Function prototypes are similar to function prototypes in C; they describe a
 function (return type, argument types, calling convention) without defining an
 implementation.  The factory functions must be called with the desired result
 type and the argument types of the function.
 
 
-.. function:: CFUNCTYPE(restype, *argtypes)
+.. function:: CFUNCTYPE(restype, *argtypes, use_errno=False, use_last_error=False)
 
    The returned function prototype creates functions that use the standard C
-   calling convention.  The function will release the GIL during the call.
+   calling convention.  The function will release the GIL during the call.  If
+   *use_errno* is set to True, the ctypes private copy of the system
+   :data:`errno` variable is exchanged with the real :data:`errno` value bafore
+   and after the call; *use_last_error* does the same for the Windows error
+   code.
+
+   .. versionchanged:: 2.6
+      The optional *use_errno* and *use_last_error* parameters were added.
 
 
-.. function:: WINFUNCTYPE(restype, *argtypes)
+.. function:: WINFUNCTYPE(restype, *argtypes, use_errno=False, use_last_error=False)
 
    Windows only: The returned function prototype creates functions that use the
-   ``stdcall`` calling convention, except on Windows CE where :func:`WINFUNCTYPE`
-   is the same as :func:`CFUNCTYPE`.  The function will release the GIL during the
-   call.
+   ``stdcall`` calling convention, except on Windows CE where
+   :func:`WINFUNCTYPE` is the same as :func:`CFUNCTYPE`.  The function will
+   release the GIL during the call.  *use_errno* and *use_last_error* have the
+   same meaning as above.
 
 
 .. function:: PYFUNCTYPE(restype, *argtypes)
 
    The returned function prototype creates functions that use the Python calling
    convention.  The function will *not* release the GIL during the call.
 
-Function prototypes created by the factory functions can be instantiated in
-different ways, depending on the type and number of the parameters in the call.
-
-
-.. function:: prototype(address)
-   :noindex:
-
-   Returns a foreign function at the specified address.
-
-
-.. function:: prototype(callable)
-   :noindex:
+Function prototypes created by these factory functions can be instantiated in
+different ways, depending on the type and number of the parameters in the call:
 
-   Create a C callable function (a callback function) from a Python ``callable``.
 
+   .. function:: prototype(address)
+      :noindex:
+      :module:
 
-.. function:: prototype(func_spec[, paramflags])
-   :noindex:
+      Returns a foreign function at the specified address which must be an integer.
 
-   Returns a foreign function exported by a shared library. ``func_spec`` must be a
-   2-tuple ``(name_or_ordinal, library)``. The first item is the name of the
-   exported function as string, or the ordinal of the exported function as small
-   integer.  The second item is the shared library instance.
 
+   .. function:: prototype(callable)
+      :noindex:
+      :module:
 
-.. function:: prototype(vtbl_index, name[, paramflags[, iid]])
-   :noindex:
+      Create a C callable function (a callback function) from a Python ``callable``.
 
-   Returns a foreign function that will call a COM method. ``vtbl_index`` is the
-   index into the virtual function table, a small nonnegative integer. *name* is
-   name of the COM method. *iid* is an optional pointer to the interface identifier
-   which is used in extended error reporting.
 
-   COM methods use a special calling convention: They require a pointer to the COM
-   interface as first argument, in addition to those parameters that are specified
-   in the :attr:`argtypes` tuple.
+   .. function:: prototype(func_spec[, paramflags])
+      :noindex:
+      :module:
 
-The optional *paramflags* parameter creates foreign function wrappers with much
-more functionality than the features described above.
+      Returns a foreign function exported by a shared library. ``func_spec`` must be a
+      2-tuple ``(name_or_ordinal, library)``. The first item is the name of the
+      exported function as string, or the ordinal of the exported function as small
+      integer.  The second item is the shared library instance.
 
-*paramflags* must be a tuple of the same length as :attr:`argtypes`.
 
-Each item in this tuple contains further information about a parameter, it must
-be a tuple containing 1, 2, or 3 items.
+   .. function:: prototype(vtbl_index, name[, paramflags[, iid]])
+      :noindex:
+      :module:
 
-The first item is an integer containing flags for the parameter:
+      Returns a foreign function that will call a COM method. ``vtbl_index`` is the
+      index into the virtual function table, a small non-negative integer. *name* is
+      name of the COM method. *iid* is an optional pointer to the interface identifier
+      which is used in extended error reporting.
 
+      COM methods use a special calling convention: They require a pointer to the COM
+      interface as first argument, in addition to those parameters that are specified
+      in the :attr:`argtypes` tuple.
 
-.. data:: 1
-   :noindex:
+   The optional *paramflags* parameter creates foreign function wrappers with much
+   more functionality than the features described above.
 
-   Specifies an input parameter to the function.
+   *paramflags* must be a tuple of the same length as :attr:`argtypes`.
 
+   Each item in this tuple contains further information about a parameter, it must
+   be a tuple containing one, two, or three items.
 
-.. data:: 2
-   :noindex:
+   The first item is an integer containing a combination of direction
+   flags for the parameter:
 
-   Output parameter.  The foreign function fills in a value.
+      1
+         Specifies an input parameter to the function.
 
+      2
+         Output parameter.  The foreign function fills in a value.
 
-.. data:: 4
-   :noindex:
-
-   Input parameter which defaults to the integer zero.
+      4
+         Input parameter which defaults to the integer zero.
 
-The optional second item is the parameter name as string.  If this is specified,
-the foreign function can be called with named parameters.
+   The optional second item is the parameter name as string.  If this is specified,
+   the foreign function can be called with named parameters.
 
-The optional third item is the default value for this parameter.
+   The optional third item is the default value for this parameter.
 
 This example demonstrates how to wrap the Windows ``MessageBoxA`` function so
 that it supports default parameters and named arguments. The C declaration from
 the windows header file is this::
 
    WINUSERAPI int WINAPI
    MessageBoxA(
        HWND hWnd ,
        LPCSTR lpText,
        LPCSTR lpCaption,
        UINT uType);
 
-Here is the wrapping with ``ctypes``:
+Here is the wrapping with ``ctypes``::
 
-   ::
-
-      >>> from ctypes import c_int, WINFUNCTYPE, windll
-      >>> from ctypes.wintypes import HWND, LPCSTR, UINT
-      >>> prototype = WINFUNCTYPE(c_int, HWND, LPCSTR, LPCSTR, c_uint)
-      >>> paramflags = (1, "hwnd", 0), (1, "text", "Hi"), (1, "caption", None), (1, "flags", 0)
-      >>> MessageBox = prototype(("MessageBoxA", windll.user32), paramflags)
-      >>>
+   >>> from ctypes import c_int, WINFUNCTYPE, windll
+   >>> from ctypes.wintypes import HWND, LPCSTR, UINT
+   >>> prototype = WINFUNCTYPE(c_int, HWND, LPCSTR, LPCSTR, UINT)
+   >>> paramflags = (1, "hwnd", 0), (1, "text", "Hi"), (1, "caption", None), (1, "flags", 0)
+   >>> MessageBox = prototype(("MessageBoxA", windll.user32), paramflags)
+   >>>
 
 The MessageBox foreign function can now be called in these ways::
 
    >>> MessageBox()
    >>> MessageBox(text="Spam, spam, spam")
    >>> MessageBox(flags=2, text="foo bar")
    >>>
 
 A second example demonstrates output parameters.  The win32 ``GetWindowRect``
 function retrieves the dimensions of a specified window by copying them into
 ``RECT`` structure that the caller has to supply.  Here is the C declaration::
 
    WINUSERAPI BOOL WINAPI
    GetWindowRect(
         HWND hWnd,
         LPRECT lpRect);
 
-Here is the wrapping with ``ctypes``:
+Here is the wrapping with ``ctypes``::
 
-   ::
-
-      >>> from ctypes import POINTER, WINFUNCTYPE, windll
-      >>> from ctypes.wintypes import BOOL, HWND, RECT
-      >>> prototype = WINFUNCTYPE(BOOL, HWND, POINTER(RECT))
-      >>> paramflags = (1, "hwnd"), (2, "lprect")
-      >>> GetWindowRect = prototype(("GetWindowRect", windll.user32), paramflags)
-      >>>
+   >>> from ctypes import POINTER, WINFUNCTYPE, windll, WinError
+   >>> from ctypes.wintypes import BOOL, HWND, RECT
+   >>> prototype = WINFUNCTYPE(BOOL, HWND, POINTER(RECT))
+   >>> paramflags = (1, "hwnd"), (2, "lprect")
+   >>> GetWindowRect = prototype(("GetWindowRect", windll.user32), paramflags)
+   >>>
 
 Functions with output parameters will automatically return the output parameter
 value if there is a single one, or a tuple containing the output parameter
 values when there are more than one, so the GetWindowRect function now returns a
 RECT instance, when called.
 
 Output parameters can be combined with the :attr:`errcheck` protocol to do
 further output processing and error checking.  The win32 ``GetWindowRect`` api
 function returns a ``BOOL`` to signal success or failure, so this function could
 do the error checking, and raises an exception when the api call failed::
 
    >>> def errcheck(result, func, args):
    ...     if not result:
    ...         raise WinError()
    ...     return args
+   ...
    >>> GetWindowRect.errcheck = errcheck
    >>>
 
 If the :attr:`errcheck` function returns the argument tuple it receives
 unchanged, ``ctypes`` continues the normal processing it does on the output
 parameters.  If you want to return a tuple of window coordinates instead of a
 ``RECT`` instance, you can retrieve the fields in the function and return them
 instead, the normal processing will no longer take place::
 
    >>> def errcheck(result, func, args):
    ...     if not result:
    ...         raise WinError()
    ...     rc = args[1]
    ...     return rc.left, rc.top, rc.bottom, rc.right
-   >>>
+   ...
    >>> GetWindowRect.errcheck = errcheck
    >>>
 
 
 .. _ctypes-utility-functions:
 
 Utility functions
 ^^^^^^^^^^^^^^^^^
 
 
 .. function:: addressof(obj)
 
    Returns the address of the memory buffer as integer.  ``obj`` must be an
    instance of a ctypes type.
 
 
 .. function:: alignment(obj_or_type)
 
    Returns the alignment requirements of a ctypes type. ``obj_or_type`` must be a
    ctypes type or instance.
 
 
-.. function:: byref(obj)
+.. function:: byref(obj[, offset])
 
-   Returns a light-weight pointer to ``obj``, which must be an instance of a ctypes
-   type. The returned object can only be used as a foreign function call parameter.
-   It behaves similar to ``pointer(obj)``, but the construction is a lot faster.
+   Returns a light-weight pointer to ``obj``, which must be an
+   instance of a ctypes type.  ``offset`` defaults to zero, and must be
+   an integer that will be added to the internal pointer value.
 
+   ``byref(obj, offset)`` corresponds to this C code::
+
+      (((char *)&obj) + offset)
+
+   The returned object can only be used as a foreign function call
+   parameter.  It behaves similar to ``pointer(obj)``, but the
+   construction is a lot faster.
+
+   .. versionadded:: 2.6
+      The ``offset`` optional argument was added.
 
 .. function:: cast(obj, type)
 
    This function is similar to the cast operator in C. It returns a new instance of
    ``type`` which points to the same memory block as ``obj``. ``type`` must be a
    pointer type, and ``obj`` must be an object that can be interpreted as a
    pointer.
 
 
 .. function:: create_string_buffer(init_or_size[, size])
 
    This function creates a mutable character buffer. The returned object is a
@@ -1818,47 +1841,89 @@
    If a unicode string is specified as first argument, the buffer is made one item
    larger than the length of the string so that the last element in the array is a
    NUL termination character. An integer can be passed as second argument which
    allows to specify the size of the array if the length of the string should not
    be used.
 
    If the first parameter is a 8-bit string, it is converted into an unicode string
    according to ctypes conversion rules.
 
 
 .. function:: DllCanUnloadNow()
 
-   Windows only: This function is a hook which allows to implement inprocess COM
+   Windows only: This function is a hook which allows to implement in-process COM
    servers with ctypes. It is called from the DllCanUnloadNow function that the
    _ctypes extension dll exports.
 
 
 .. function:: DllGetClassObject()
 
-   Windows only: This function is a hook which allows to implement inprocess COM
+   Windows only: This function is a hook which allows to implement in-process COM
    servers with ctypes. It is called from the DllGetClassObject function that the
    ``_ctypes`` extension dll exports.
 
+.. function:: find_library(name)
+   :module: ctypes.util
+
+   Try to find a library and return a pathname.  *name* is the library name
+   without any prefix like ``lib``, suffix like ``.so``, ``.dylib`` or version
+   number (this is the form used for the posix linker option :option:`-l`).  If
+   no library can be found, returns ``None``.
+
+   The exact functionality is system dependent.
+
+   .. versionchanged:: 2.6
+      Windows only: ``find_library("m")`` or
+      ``find_library("c")`` return the result of a call to
+      ``find_msvcrt()``.
+
+.. function:: find_msvcrt()
+   :module: ctypes.util
+
+   Windows only: return the filename of the VC runtype library used
+   by Python, and by the extension modules.  If the name of the
+   library cannot be determined, ``None`` is returned.
+
+   If you need to free memory, for example, allocated by an extension
+   module with a call to the ``free(void *)``, it is important that you
+   use the function in the same library that allocated the memory.
+
+   .. versionadded:: 2.6
 
 .. function:: FormatError([code])
 
    Windows only: Returns a textual description of the error code. If no error code
    is specified, the last error code is used by calling the Windows api function
    GetLastError.
 
 
 .. function:: GetLastError()
 
    Windows only: Returns the last error code set by Windows in the calling thread.
+   This function calls the Windows `GetLastError()` function directly,
+   it does not return the ctypes-private copy of the error code.
+
+.. function:: get_errno()
+
+   Returns the current value of the ctypes-private copy of the system
+   :data:`errno` variable in the calling thread.
+
+   .. versionadded:: 2.6
 
+.. function:: get_last_error()
+
+   Windows only: returns the current value of the ctypes-private copy of the system
+   :data:`LastError` variable in the calling thread.
+
+   .. versionadded:: 2.6
 
 .. function:: memmove(dst, src, count)
 
    Same as the standard C memmove library function: copies *count* bytes from
    ``src`` to *dst*. *dst* and ``src`` must be integers or ctypes instances that
    can be converted to pointers.
 
 
 .. function:: memset(dst, c, count)
 
    Same as the standard C memset library function: fills the memory block at
    address *dst* with *count* bytes of value *c*. *dst* must be an integer
@@ -1893,156 +1958,199 @@
 
    This function sets the rules that ctypes objects use when converting between
    8-bit strings and unicode strings. encoding must be a string specifying an
    encoding, like ``'utf-8'`` or ``'mbcs'``, errors must be a string specifying the
    error handling on encoding/decoding errors. Examples of possible values are
    ``"strict"``, ``"replace"``, or ``"ignore"``.
 
    ``set_conversion_mode`` returns a 2-tuple containing the previous conversion
    rules. On windows, the initial conversion rules are ``('mbcs', 'ignore')``, on
    other systems ``('ascii', 'strict')``.
 
 
+.. function:: set_errno(value)
+
+   Set the current value of the ctypes-private copy of the system :data:`errno`
+   variable in the calling thread to *value* and return the previous value.
+
+   .. versionadded:: 2.6
+
+.. function:: set_last_error(value)
+
+   Windows only: set the current value of the ctypes-private copy of the system
+   :data:`LastError` variable in the calling thread to *value* and return the
+   previous value.
+
+   .. versionadded:: 2.6
+
 .. function:: sizeof(obj_or_type)
 
    Returns the size in bytes of a ctypes type or instance memory buffer. Does the
    same as the C ``sizeof()`` function.
 
 
 .. function:: string_at(address[, size])
 
-   This function returns the string starting at memory address address. If size is
-   specified, it is used as size, otherwise the string is assumed to be zero-
-   terminated.
+   This function returns the string starting at memory address address. If size
+   is specified, it is used as size, otherwise the string is assumed to be
+   zero-terminated.
 
 
 .. function:: WinError(code=None, descr=None)
 
    Windows only: this function is probably the worst-named thing in ctypes. It
    creates an instance of WindowsError. If *code* is not specified,
    ``GetLastError`` is called to determine the error code. If ``descr`` is not
-   spcified, :func:`FormatError` is called to get a textual description of the
+   specified, :func:`FormatError` is called to get a textual description of the
    error.
 
 
 .. function:: wstring_at(address)
 
    This function returns the wide character string starting at memory address
    ``address`` as unicode string. If ``size`` is specified, it is used as the
-   number of characters of the string, otherwise the string is assumed to be zero-
-   terminated.
+   number of characters of the string, otherwise the string is assumed to be
+   zero-terminated.
 
 
 .. _ctypes-data-types:
 
 Data types
 ^^^^^^^^^^
 
 
 .. class:: _CData
 
    This non-public class is the common base class of all ctypes data types.  Among
    other things, all ctypes type instances contain a memory block that hold C
    compatible data; the address of the memory block is returned by the
    ``addressof()`` helper function. Another instance variable is exposed as
    :attr:`_objects`; this contains other Python objects that need to be kept alive
    in case the memory block contains pointers.
 
-Common methods of ctypes data types, these are all class methods (to be exact,
-they are methods of the metaclass):
+   Common methods of ctypes data types, these are all class methods (to be
+   exact, they are methods of the :term:`metaclass`):
 
 
-.. method:: _CData.from_address(address)
+   .. method:: _CData.from_buffer(source[, offset])
 
-   This method returns a ctypes type instance using the memory specified by address
-   which must be an integer.
+      This method returns a ctypes instance that shares the buffer of
+      the ``source`` object.  The ``source`` object must support the
+      writeable buffer interface.  The optional ``offset`` parameter
+      specifies an offset into the source buffer in bytes; the default
+      is zero.  If the source buffer is not large enough a ValueError
+      is raised.
 
+      .. versionadded:: 2.6
 
-.. method:: _CData.from_param(obj)
+   .. method:: _CData.from_buffer_copy(source[, offset])
 
-   This method adapts obj to a ctypes type.  It is called with the actual object
-   used in a foreign function call, when the type is present in the foreign
-   functions :attr:`argtypes` tuple; it must return an object that can be used as
-   function call parameter.
+      This method creates a ctypes instance, copying the buffer from
+      the source object buffer which must be readable.  The optional
+      ``offset`` parameter specifies an offset into the source buffer
+      in bytes; the default is zero.  If the source buffer is not
+      large enough a ValueError is raised.
 
-   All ctypes data types have a default implementation of this classmethod,
-   normally it returns ``obj`` if that is an instance of the type.  Some types
-   accept other objects as well.
+      .. versionadded:: 2.6
 
 
-.. method:: _CData.in_dll(name, library)
+   .. method:: from_address(address)
 
-   This method returns a ctypes type instance exported by a shared library. *name*
-   is the name of the symbol that exports the data, ``library`` is the loaded
-   shared library.
+      This method returns a ctypes type instance using the memory specified by
+      address which must be an integer.
 
-Common instance variables of ctypes data types:
 
+   .. method:: from_param(obj)
 
-.. attribute:: _CData._b_base_
+      This method adapts *obj* to a ctypes type.  It is called with the actual
+      object used in a foreign function call when the type is present in the
+      foreign function's :attr:`argtypes` tuple; it must return an object that
+      can be used as a function call parameter.
 
-   Sometimes ctypes data instances do not own the memory block they contain,
-   instead they share part of the memory block of a base object.  The
-   :attr:`_b_base_` readonly member is the root ctypes object that owns the memory
-   block.
+      All ctypes data types have a default implementation of this classmethod
+      that normally returns ``obj`` if that is an instance of the type.  Some
+      types accept other objects as well.
 
 
-.. attribute:: _CData._b_needsfree_
+   .. method:: in_dll(library, name)
 
-   This readonly variable is true when the ctypes data instance has allocated the
-   memory block itself, false otherwise.
+      This method returns a ctypes type instance exported by a shared
+      library. *name* is the name of the symbol that exports the data, *library*
+      is the loaded shared library.
 
 
-.. attribute:: _CData._objects
+   Common instance variables of ctypes data types:
 
-   This member is either ``None`` or a dictionary containing Python objects that
-   need to be kept alive so that the memory block contents is kept valid.  This
-   object is only exposed for debugging; never modify the contents of this
-   dictionary.
 
+   .. attribute:: _b_base_
 
-.. _ctypes-fundamental-data-types:
+      Sometimes ctypes data instances do not own the memory block they contain,
+      instead they share part of the memory block of a base object.  The
+      :attr:`_b_base_` read-only member is the root ctypes object that owns the
+      memory block.
+
+
+   .. attribute:: _b_needsfree_
+
+      This read-only variable is true when the ctypes data instance has
+      allocated the memory block itself, false otherwise.
+
+
+   .. attribute:: _objects
+
+      This member is either ``None`` or a dictionary containing Python objects
+      that need to be kept alive so that the memory block contents is kept
+      valid.  This object is only exposed for debugging; never modify the
+      contents of this dictionary.
+
+
+.. _ctypes-fundamental-data-types-2:
 
 Fundamental data types
 ^^^^^^^^^^^^^^^^^^^^^^
 
 
 .. class:: _SimpleCData
 
    This non-public class is the base class of all fundamental ctypes data types. It
    is mentioned here because it contains the common attributes of the fundamental
    ctypes data types.  ``_SimpleCData`` is a subclass of ``_CData``, so it inherits
    their methods and attributes.
 
-Instances have a single attribute:
+   .. versionchanged:: 2.6
+      ctypes data types that are not and do not contain pointers can
+      now be pickled.
+
+   Instances have a single attribute:
 
 
-.. attribute:: _SimpleCData.value
+   .. attribute:: value
 
-   This attribute contains the actual value of the instance. For integer and
-   pointer types, it is an integer, for character types, it is a single character
-   string, for character pointer types it is a Python string or unicode string.
+      This attribute contains the actual value of the instance. For integer and
+      pointer types, it is an integer, for character types, it is a single
+      character string, for character pointer types it is a Python string or
+      unicode string.
 
-   When the ``value`` attribute is retrieved from a ctypes instance, usually a new
-   object is returned each time.  ``ctypes`` does *not* implement original object
-   return, always a new object is constructed.  The same is true for all other
-   ctypes object instances.
+      When the ``value`` attribute is retrieved from a ctypes instance, usually
+      a new object is returned each time.  ``ctypes`` does *not* implement
+      original object return, always a new object is constructed.  The same is
+      true for all other ctypes object instances.
 
 Fundamental data types, when returned as foreign function call results, or, for
 example, by retrieving structure field members or array items, are transparently
 converted to native Python types.  In other words, if a foreign function has a
 :attr:`restype` of :class:`c_char_p`, you will always receive a Python string,
 *not* a :class:`c_char_p` instance.
 
-Subclasses of fundamental data types do *not* inherit this behaviour. So, if a
+Subclasses of fundamental data types do *not* inherit this behavior. So, if a
 foreign functions :attr:`restype` is a subclass of :class:`c_void_p`, you will
 receive an instance of this subclass from the function call. Of course, you can
 get the value of the pointer by accessing the ``value`` attribute.
 
 These are the fundamental ctypes data types:
 
 
 .. class:: c_byte
 
    Represents the C signed char datatype, and interprets the value as small
    integer. The constructor accepts an optional integer initializer; no overflow
    checking is done.
@@ -2058,27 +2166,35 @@
 .. class:: c_char_p
 
    Represents the C char \* datatype, which must be a pointer to a zero-terminated
    string. The constructor accepts an integer address, or a string.
 
 
 .. class:: c_double
 
    Represents the C double datatype. The constructor accepts an optional float
    initializer.
 
 
+.. class:: c_longdouble
+
+   Represents the C long double datatype. The constructor accepts an
+   optional float initializer.  On platforms where ``sizeof(long
+   double) == sizeof(double)`` it is an alias to :class:`c_double`.
+
+   .. versionadded:: 2.6
+
 .. class:: c_float
 
-   Represents the C double datatype. The constructor accepts an optional float
+   Represents the C float datatype. The constructor accepts an optional float
    initializer.
 
 
 .. class:: c_int
 
    Represents the C signed int datatype. The constructor accepts an optional
    integer initializer; no overflow checking is done. On platforms where
    ``sizeof(int) == sizeof(long)`` it is an alias to :class:`c_long`.
 
 
 .. class:: c_int8
 
@@ -2189,39 +2305,48 @@
    constructor accepts an optional integer initializer.
 
 
 .. class:: c_wchar
 
    Represents the C ``wchar_t`` datatype, and interprets the value as a single
    character unicode string. The constructor accepts an optional string
    initializer, the length of the string must be exactly one character.
 
 
 .. class:: c_wchar_p
 
-   Represents the C ``wchar_t *`` datatype, which must be a pointer to a zero-
-   terminated wide character string. The constructor accepts an integer address, or
-   a string.
+   Represents the C ``wchar_t *`` datatype, which must be a pointer to a
+   zero-terminated wide character string. The constructor accepts an integer
+   address, or a string.
+
+
+.. class:: c_bool
+
+   Represent the C ``bool`` datatype (more accurately, _Bool from C99). Its value
+   can be True or False, and the constructor accepts any object that has a truth
+   value.
+
+   .. versionadded:: 2.6
 
 
 .. class:: HRESULT
 
    Windows only: Represents a :class:`HRESULT` value, which contains success or
    error information for a function or method call.
 
-``py_object`` : classdesc\*
 
-   Represents the C ``PyObject *`` datatype.  Calling this with an without an
-   argument creates a ``NULL`` ``PyObject *`` pointer.
+.. class:: py_object
 
+   Represents the C ``PyObject *`` datatype.  Calling this without an argument
+   creates a ``NULL`` ``PyObject *`` pointer.
 
 The ``ctypes.wintypes`` module provides quite some other Windows specific data
 types, for example ``HWND``, ``WPARAM``, or ``DWORD``. Some useful structures
 like ``MSG`` or ``RECT`` are also defined.
 
 
 .. _ctypes-structured-data-types:
 
 Structured data types
 ^^^^^^^^^^^^^^^^^^^^^
 
 
@@ -2238,117 +2363,120 @@
 .. class:: LittleEndianStructure(*args, **kw)
 
    Abstract base class for structures in *little endian* byte order.
 
 Structures with non-native byte order cannot contain pointer type fields, or any
 other data types containing pointer type fields.
 
 
 .. class:: Structure(*args, **kw)
 
    Abstract base class for structures in *native* byte order.
 
-Concrete structure and union types must be created by subclassing one of these
-types, and at least define a :attr:`_fields_` class variable. ``ctypes`` will
-create descriptors which allow reading and writing the fields by direct
-attribute accesses.  These are the
+   Concrete structure and union types must be created by subclassing one of these
+   types, and at least define a :attr:`_fields_` class variable. ``ctypes`` will
+   create :term:`descriptor`\s which allow reading and writing the fields by direct
+   attribute accesses.  These are the
 
 
-.. attribute:: Structure._fields_
+   .. attribute:: _fields_
 
-   A sequence defining the structure fields.  The items must be 2-tuples or
-   3-tuples.  The first item is the name of the field, the second item specifies
-   the type of the field; it can be any ctypes data type.
+      A sequence defining the structure fields.  The items must be 2-tuples or
+      3-tuples.  The first item is the name of the field, the second item
+      specifies the type of the field; it can be any ctypes data type.
 
-   For integer type fields like :class:`c_int`, a third optional item can be given.
-   It must be a small positive integer defining the bit width of the field.
+      For integer type fields like :class:`c_int`, a third optional item can be
+      given.  It must be a small positive integer defining the bit width of the
+      field.
 
-   Field names must be unique within one structure or union.  This is not checked,
-   only one field can be accessed when names are repeated.
+      Field names must be unique within one structure or union.  This is not
+      checked, only one field can be accessed when names are repeated.
 
-   It is possible to define the :attr:`_fields_` class variable *after* the class
-   statement that defines the Structure subclass, this allows to create data types
-   that directly or indirectly reference themselves::
+      It is possible to define the :attr:`_fields_` class variable *after* the
+      class statement that defines the Structure subclass, this allows to create
+      data types that directly or indirectly reference themselves::
 
-      class List(Structure):
-          pass
-      List._fields_ = [("pnext", POINTER(List)),
-                       ...
-                      ]
+         class List(Structure):
+             pass
+         List._fields_ = [("pnext", POINTER(List)),
+                          ...
+                         ]
 
-   The :attr:`_fields_` class variable must, however, be defined before the type is
-   first used (an instance is created, ``sizeof()`` is called on it, and so on).
-   Later assignments to the :attr:`_fields_` class variable will raise an
-   AttributeError.
+      The :attr:`_fields_` class variable must, however, be defined before the
+      type is first used (an instance is created, ``sizeof()`` is called on it,
+      and so on).  Later assignments to the :attr:`_fields_` class variable will
+      raise an AttributeError.
 
-   Structure and union subclass constructors accept both positional and named
-   arguments.  Positional arguments are used to initialize the fields in the same
-   order as they appear in the :attr:`_fields_` definition, named arguments are
-   used to initialize the fields with the corresponding name.
+      Structure and union subclass constructors accept both positional and named
+      arguments.  Positional arguments are used to initialize the fields in the
+      same order as they appear in the :attr:`_fields_` definition, named
+      arguments are used to initialize the fields with the corresponding name.
 
-   It is possible to defined sub-subclasses of structure types, they inherit the
-   fields of the base class plus the :attr:`_fields_` defined in the sub-subclass,
-   if any.
+      It is possible to defined sub-subclasses of structure types, they inherit
+      the fields of the base class plus the :attr:`_fields_` defined in the
+      sub-subclass, if any.
 
 
-.. attribute:: Structure._pack_
+   .. attribute:: _pack_
 
-   An optional small integer that allows to override the alignment of structure
-   fields in the instance.  :attr:`_pack_` must already be defined when
-   :attr:`_fields_` is assigned, otherwise it will have no effect.
+      An optional small integer that allows to override the alignment of
+      structure fields in the instance.  :attr:`_pack_` must already be defined
+      when :attr:`_fields_` is assigned, otherwise it will have no effect.
 
 
-.. attribute:: Structure._anonymous_
+   .. attribute:: _anonymous_
 
-   An optional sequence that lists the names of unnamed (anonymous) fields.
-   ``_anonymous_`` must be already defined when :attr:`_fields_` is assigned,
-   otherwise it will have no effect.
+      An optional sequence that lists the names of unnamed (anonymous) fields.
+      ``_anonymous_`` must be already defined when :attr:`_fields_` is assigned,
+      otherwise it will have no effect.
 
-   The fields listed in this variable must be structure or union type fields.
-   ``ctypes`` will create descriptors in the structure type that allows to access
-   the nested fields directly, without the need to create the structure or union
-   field.
+      The fields listed in this variable must be structure or union type fields.
+      ``ctypes`` will create descriptors in the structure type that allows to
+      access the nested fields directly, without the need to create the
+      structure or union field.
 
-   Here is an example type (Windows)::
+      Here is an example type (Windows)::
 
-      class _U(Union):
-          _fields_ = [("lptdesc", POINTER(TYPEDESC)),
-                      ("lpadesc", POINTER(ARRAYDESC)),
-                      ("hreftype", HREFTYPE)]
+         class _U(Union):
+             _fields_ = [("lptdesc", POINTER(TYPEDESC)),
+                         ("lpadesc", POINTER(ARRAYDESC)),
+                         ("hreftype", HREFTYPE)]
 
-      class TYPEDESC(Structure):
-          _fields_ = [("u", _U),
-                      ("vt", VARTYPE)]
+         class TYPEDESC(Structure):
+             _fields_ = [("u", _U),
+                         ("vt", VARTYPE)]
 
-          _anonymous_ = ("u",)
+             _anonymous_ = ("u",)
 
-   The ``TYPEDESC`` structure describes a COM data type, the ``vt`` field specifies
-   which one of the union fields is valid.  Since the ``u`` field is defined as
-   anonymous field, it is now possible to access the members directly off the
-   TYPEDESC instance. ``td.lptdesc`` and ``td.u.lptdesc`` are equivalent, but the
-   former is faster since it does not need to create a temporary union instance::
+      The ``TYPEDESC`` structure describes a COM data type, the ``vt`` field
+      specifies which one of the union fields is valid.  Since the ``u`` field
+      is defined as anonymous field, it is now possible to access the members
+      directly off the TYPEDESC instance. ``td.lptdesc`` and ``td.u.lptdesc``
+      are equivalent, but the former is faster since it does not need to create
+      a temporary union instance::
 
-      td = TYPEDESC()
-      td.vt = VT_PTR
-      td.lptdesc = POINTER(some_type)
-      td.u.lptdesc = POINTER(some_type)
+         td = TYPEDESC()
+         td.vt = VT_PTR
+         td.lptdesc = POINTER(some_type)
+         td.u.lptdesc = POINTER(some_type)
 
 It is possible to defined sub-subclasses of structures, they inherit the fields
 of the base class.  If the subclass definition has a separate :attr:`_fields_`
 variable, the fields specified in this are appended to the fields of the base
 class.
 
 Structure and union constructors accept both positional and keyword arguments.
 Positional arguments are used to initialize member fields in the same order as
 they are appear in :attr:`_fields_`.  Keyword arguments in the constructor are
 interpreted as attribute assignments, so they will initialize :attr:`_fields_`
 with the same name, or create new attributes for names not present in
 :attr:`_fields_`.
 
 
 .. _ctypes-arrays-pointers:
 
 Arrays and pointers
 ^^^^^^^^^^^^^^^^^^^
 
-XXX
+Not yet written - please see the sections :ref:`ctypes-pointers` and
+section :ref:`ctypes-arrays` in the tutorial.
 
