ctypes released

Thomas Heller theller at python.net
Wed Feb 15 20:47:38 CET 2006

ctypes released - Feb 15, 2006


    ctypes is an advanced ffi (Foreign Function Interface) package for
    Python 2.3 and higher.

    ctypes allows to call functions exposed from dlls/shared libraries
    and has extensive facilities to create, access and manipulate
    simple and complicated C data types in Python - in other words:
    wrap libraries in pure Python.  It is even possible to implement C
    callback functions in pure Python.

    ctypes includes a code generator toolchain which allows
    automatic creation of library wrappers from C header files.
    This feature is still experimental and beta quality.

    ctypes runs on Windows, Windows CE, MacOS X, Linux, Solaris,
    FreeBSD, OpenBSD. It may also run on other systems, provided that
    libffi supports this platform.


    If you download the source distribution, please choose the ZIP
    file for Windows, and the .tar.gz file for other machines.
    These archive have different contents!

    There have been lots of changes - if you are the author or user of
    a package that uses ctypes, please test it with this release
    and report problems on the ctypes-users mailing list.

Changes in

    (These are the most important changes, see the ChangeLog for
    complete details)


        The ctypes.com package is no longer included and supported.
        It is replaced by the comtypes package which will be released

	ctypes has been ported to Windows CE by Luke Dunstan.

    Other platforms

        Hye-Shik Chang has written a new build system for libffi
        which should remove possible licensing issues.

    All platforms

        The library loading code has been rewritten by Andreas Degert,
        there are now sophisticated methods to find shared libraries.
	On OS X, this uses files from Bob Ippolito's macholib.
        See the manual for details.

        Finally I started to write the manual, it is available online:


	New 'errcheck' protocol to check the return values of foreign
	functions, suggested by Mike Fletcher.

	Lots of bug fixes, especially for 64-bit platforms. Improved
	performance when creating ctypes instances.

	Subclasses of simple types (c_int, c_void_p, and so on) now
	behave as expected - they are not automatically converted into
	native Python types any longer.

	Support for explicit byte ordering in structures has been
	added (BigEndianStructure, LittleEndianStructure base

	call byref() automatically, if needed, for POINTER types in

	Lots of improvements to the code generator.

Changes in 0.9.6

    Thanks to all of you who reported bugs so quickly, and those who
    tried out the codegenerator toolchain.

    Bug fixes:

    - keyword arguments in Structure/Union initializers had no effect.

    - it was impossible to override the from_parm class method
    in subclasses of c_void_p, c_char_p, and c_wchar_p.

    - removed the __del__ method of _CDLL. It caused uncollectable
    garbage in Python's gc.

    - ctypes.com.register: enclose the Python script to run a com
    server in quotes, otherwise it won't run correctly when the
    directory name contains spaces.


    - Several changes have been made to the h2xml script from the
    codegenerator toolchain. See the documentation (linked below) for

Additions in 0.9.5

    New package ctypes.wrap. This contains decorators usable for
    easier creation of wrapper functions.

    This package also contains a toolchain for (semi)automatic
    creation of wrappers for external libraries - it can parse
    C header files and generate ctypes code for the declarations in
    them.  It can even handle preprocessor definitions! For details,
    see http://starship.python.net/crew/theller/ctypes/codegen.html

Changes in 0.9.5

    On systems where sizeof(int) == sizeof(long), c_int/c_long and
    c_uint/c_ulong are now aliases.  Similar for c_long/c_longlong and
    c_ulong/c_ulonglong.  This prevents unneeded type errors.

    If an exception occurs in a callback function, a full traceback is
    now printed.  Raising SystemExit in a callback function now
    correctly exists Python.

    HRESULT is now a proper ctype - no longer a function.  This allows
    to use it in the argtypes sequence for function prototypes.

    An easier way to define structures and unions that reference
    themselves, or have dependencies to other data types.  The
    _fields_ attribute can now be set *after* the Structure/Union
    class has been created.  This makes the SetPointerType function

    The semantics of the _fields_ attribute in sub-subclasses of
    Structure and Union has been fixed.  The baseclasses _fields_ list
    is extended, not replaced, in subclasses.  Assigning _fields_ when
    it is no longer possible raises an error now.

    Structures and unions now work as restype and in the argtypes list
    for functions.

    An important bug has been fixed with pointers.

    Detailed changelog is in CVS:



    Downloads are available in the sourceforge files section

    Separate source distributions are available for windows and non-windows systems.
    Please use the .zip file for Windows and Windows CE, and use the
    .tar.gz file for non-Windows systems (it contains the complete
    cross-platform libffi sources).

    Binary windows installers, which contain compiled extension
    modules, are also available, be sure to download the correct one
    for the Python version you are using.





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