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.. highlightlang:: c
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.. _extending-intro:
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******************************
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Extending Python with C or C++
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******************************
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It is quite easy to add new built-in modules to Python, if you know how to
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program in C. Such :dfn:`extension modules` can do two things that can't be
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done directly in Python: they can implement new built-in object types, and they
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can call C library functions and system calls.
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To support extensions, the Python API (Application Programmers Interface)
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defines a set of functions, macros and variables that provide access to most
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aspects of the Python run-time system. The Python API is incorporated in a C
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source file by including the header ``"Python.h"``.
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The compilation of an extension module depends on its intended use as well as on
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your system setup; details are given in later chapters.
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2015-01-05 16:38:46 -04:00
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.. note::
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The C extension interface is specific to CPython, and extension modules do
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not work on other Python implementations. In many cases, it is possible to
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avoid writing C extensions and preserve portability to other implementations.
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For example, if your use case is calling C library functions or system calls,
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you should consider using the :mod:`ctypes` module or the `cffi
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<https://cffi.readthedocs.org>`_ library rather than writing custom C code.
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These modules let you write Python code to interface with C code and are more
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portable between implementations of Python than writing and compiling a C
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extension module.
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.. _extending-simpleexample:
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A Simple Example
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================
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Let's create an extension module called ``spam`` (the favorite food of Monty
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Python fans...) and let's say we want to create a Python interface to the C
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library function :c:func:`system`. [#]_ This function takes a null-terminated
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character string as argument and returns an integer. We want this function to
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be callable from Python as follows::
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>>> import spam
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>>> status = spam.system("ls -l")
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Begin by creating a file :file:`spammodule.c`. (Historically, if a module is
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called ``spam``, the C file containing its implementation is called
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:file:`spammodule.c`; if the module name is very long, like ``spammify``, the
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module name can be just :file:`spammify.c`.)
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The first line of our file can be::
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#include <Python.h>
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which pulls in the Python API (you can add a comment describing the purpose of
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the module and a copyright notice if you like).
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.. note::
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Since Python may define some pre-processor definitions which affect the standard
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headers on some systems, you *must* include :file:`Python.h` before any standard
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headers are included.
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All user-visible symbols defined by :file:`Python.h` have a prefix of ``Py`` or
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``PY``, except those defined in standard header files. For convenience, and
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since they are used extensively by the Python interpreter, ``"Python.h"``
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includes a few standard header files: ``<stdio.h>``, ``<string.h>``,
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``<errno.h>``, and ``<stdlib.h>``. If the latter header file does not exist on
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your system, it declares the functions :c:func:`malloc`, :c:func:`free` and
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:c:func:`realloc` directly.
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The next thing we add to our module file is the C function that will be called
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when the Python expression ``spam.system(string)`` is evaluated (we'll see
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shortly how it ends up being called)::
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static PyObject *
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spam_system(PyObject *self, PyObject *args)
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{
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const char *command;
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int sts;
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if (!PyArg_ParseTuple(args, "s", &command))
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return NULL;
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sts = system(command);
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return PyLong_FromLong(sts);
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}
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There is a straightforward translation from the argument list in Python (for
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example, the single expression ``"ls -l"``) to the arguments passed to the C
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function. The C function always has two arguments, conventionally named *self*
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and *args*.
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The *self* argument points to the module object for module-level functions;
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for a method it would point to the object instance.
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The *args* argument will be a pointer to a Python tuple object containing the
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arguments. Each item of the tuple corresponds to an argument in the call's
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argument list. The arguments are Python objects --- in order to do anything
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with them in our C function we have to convert them to C values. The function
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:c:func:`PyArg_ParseTuple` in the Python API checks the argument types and
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converts them to C values. It uses a template string to determine the required
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types of the arguments as well as the types of the C variables into which to
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store the converted values. More about this later.
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:c:func:`PyArg_ParseTuple` returns true (nonzero) if all arguments have the right
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type and its components have been stored in the variables whose addresses are
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passed. It returns false (zero) if an invalid argument list was passed. In the
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latter case it also raises an appropriate exception so the calling function can
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return *NULL* immediately (as we saw in the example).
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.. _extending-errors:
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Intermezzo: Errors and Exceptions
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=================================
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An important convention throughout the Python interpreter is the following: when
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a function fails, it should set an exception condition and return an error value
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(usually a *NULL* pointer). Exceptions are stored in a static global variable
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inside the interpreter; if this variable is *NULL* no exception has occurred. A
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second global variable stores the "associated value" of the exception (the
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second argument to :keyword:`raise`). A third variable contains the stack
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traceback in case the error originated in Python code. These three variables
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are the C equivalents of the result in Python of :meth:`sys.exc_info` (see the
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section on module :mod:`sys` in the Python Library Reference). It is important
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to know about them to understand how errors are passed around.
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The Python API defines a number of functions to set various types of exceptions.
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The most common one is :c:func:`PyErr_SetString`. Its arguments are an exception
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object and a C string. The exception object is usually a predefined object like
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:c:data:`PyExc_ZeroDivisionError`. The C string indicates the cause of the error
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and is converted to a Python string object and stored as the "associated value"
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of the exception.
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Another useful function is :c:func:`PyErr_SetFromErrno`, which only takes an
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exception argument and constructs the associated value by inspection of the
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global variable :c:data:`errno`. The most general function is
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:c:func:`PyErr_SetObject`, which takes two object arguments, the exception and
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its associated value. You don't need to :c:func:`Py_INCREF` the objects passed
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to any of these functions.
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You can test non-destructively whether an exception has been set with
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:c:func:`PyErr_Occurred`. This returns the current exception object, or *NULL*
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if no exception has occurred. You normally don't need to call
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:c:func:`PyErr_Occurred` to see whether an error occurred in a function call,
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since you should be able to tell from the return value.
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When a function *f* that calls another function *g* detects that the latter
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fails, *f* should itself return an error value (usually *NULL* or ``-1``). It
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should *not* call one of the :c:func:`PyErr_\*` functions --- one has already
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been called by *g*. *f*'s caller is then supposed to also return an error
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indication to *its* caller, again *without* calling :c:func:`PyErr_\*`, and so on
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--- the most detailed cause of the error was already reported by the function
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that first detected it. Once the error reaches the Python interpreter's main
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loop, this aborts the currently executing Python code and tries to find an
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exception handler specified by the Python programmer.
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(There are situations where a module can actually give a more detailed error
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message by calling another :c:func:`PyErr_\*` function, and in such cases it is
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fine to do so. As a general rule, however, this is not necessary, and can cause
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information about the cause of the error to be lost: most operations can fail
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for a variety of reasons.)
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To ignore an exception set by a function call that failed, the exception
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condition must be cleared explicitly by calling :c:func:`PyErr_Clear`. The only
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time C code should call :c:func:`PyErr_Clear` is if it doesn't want to pass the
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error on to the interpreter but wants to handle it completely by itself
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(possibly by trying something else, or pretending nothing went wrong).
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Every failing :c:func:`malloc` call must be turned into an exception --- the
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direct caller of :c:func:`malloc` (or :c:func:`realloc`) must call
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:c:func:`PyErr_NoMemory` and return a failure indicator itself. All the
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object-creating functions (for example, :c:func:`PyLong_FromLong`) already do
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this, so this note is only relevant to those who call :c:func:`malloc` directly.
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Also note that, with the important exception of :c:func:`PyArg_ParseTuple` and
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friends, functions that return an integer status usually return a positive value
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or zero for success and ``-1`` for failure, like Unix system calls.
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Finally, be careful to clean up garbage (by making :c:func:`Py_XDECREF` or
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:c:func:`Py_DECREF` calls for objects you have already created) when you return
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an error indicator!
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The choice of which exception to raise is entirely yours. There are predeclared
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C objects corresponding to all built-in Python exceptions, such as
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:c:data:`PyExc_ZeroDivisionError`, which you can use directly. Of course, you
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should choose exceptions wisely --- don't use :c:data:`PyExc_TypeError` to mean
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that a file couldn't be opened (that should probably be :c:data:`PyExc_IOError`).
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If something's wrong with the argument list, the :c:func:`PyArg_ParseTuple`
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function usually raises :c:data:`PyExc_TypeError`. If you have an argument whose
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value must be in a particular range or must satisfy other conditions,
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:c:data:`PyExc_ValueError` is appropriate.
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You can also define a new exception that is unique to your module. For this, you
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usually declare a static object variable at the beginning of your file::
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static PyObject *SpamError;
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and initialize it in your module's initialization function (:c:func:`PyInit_spam`)
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with an exception object (leaving out the error checking for now)::
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PyMODINIT_FUNC
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PyInit_spam(void)
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{
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PyObject *m;
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m = PyModule_Create(&spammodule);
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if (m == NULL)
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return NULL;
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SpamError = PyErr_NewException("spam.error", NULL, NULL);
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Py_INCREF(SpamError);
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PyModule_AddObject(m, "error", SpamError);
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return m;
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}
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Note that the Python name for the exception object is :exc:`spam.error`. The
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:c:func:`PyErr_NewException` function may create a class with the base class
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being :exc:`Exception` (unless another class is passed in instead of *NULL*),
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described in :ref:`bltin-exceptions`.
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Note also that the :c:data:`SpamError` variable retains a reference to the newly
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created exception class; this is intentional! Since the exception could be
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removed from the module by external code, an owned reference to the class is
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needed to ensure that it will not be discarded, causing :c:data:`SpamError` to
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become a dangling pointer. Should it become a dangling pointer, C code which
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raises the exception could cause a core dump or other unintended side effects.
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We discuss the use of ``PyMODINIT_FUNC`` as a function return type later in this
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sample.
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The :exc:`spam.error` exception can be raised in your extension module using a
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call to :c:func:`PyErr_SetString` as shown below::
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static PyObject *
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spam_system(PyObject *self, PyObject *args)
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{
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const char *command;
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int sts;
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if (!PyArg_ParseTuple(args, "s", &command))
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return NULL;
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sts = system(command);
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if (sts < 0) {
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PyErr_SetString(SpamError, "System command failed");
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return NULL;
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}
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return PyLong_FromLong(sts);
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}
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.. _backtoexample:
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Back to the Example
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===================
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Going back to our example function, you should now be able to understand this
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statement::
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if (!PyArg_ParseTuple(args, "s", &command))
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return NULL;
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It returns *NULL* (the error indicator for functions returning object pointers)
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if an error is detected in the argument list, relying on the exception set by
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:c:func:`PyArg_ParseTuple`. Otherwise the string value of the argument has been
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copied to the local variable :c:data:`command`. This is a pointer assignment and
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you are not supposed to modify the string to which it points (so in Standard C,
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the variable :c:data:`command` should properly be declared as ``const char
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*command``).
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The next statement is a call to the Unix function :c:func:`system`, passing it
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the string we just got from :c:func:`PyArg_ParseTuple`::
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sts = system(command);
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Our :func:`spam.system` function must return the value of :c:data:`sts` as a
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Python object. This is done using the function :c:func:`PyLong_FromLong`. ::
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return PyLong_FromLong(sts);
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In this case, it will return an integer object. (Yes, even integers are objects
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on the heap in Python!)
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If you have a C function that returns no useful argument (a function returning
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:c:type:`void`), the corresponding Python function must return ``None``. You
|
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need this idiom to do so (which is implemented by the :c:macro:`Py_RETURN_NONE`
|
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macro)::
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Py_INCREF(Py_None);
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return Py_None;
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:c:data:`Py_None` is the C name for the special Python object ``None``. It is a
|
2007-08-15 11:28:22 -03:00
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genuine Python object rather than a *NULL* pointer, which means "error" in most
|
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contexts, as we have seen.
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.. _methodtable:
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The Module's Method Table and Initialization Function
|
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|
=====================================================
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2010-10-06 07:11:56 -03:00
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I promised to show how :c:func:`spam_system` is called from Python programs.
|
2007-08-15 11:28:22 -03:00
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First, we need to list its name and address in a "method table"::
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static PyMethodDef SpamMethods[] = {
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...
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{"system", spam_system, METH_VARARGS,
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"Execute a shell command."},
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...
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{NULL, NULL, 0, NULL} /* Sentinel */
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};
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Note the third entry (``METH_VARARGS``). This is a flag telling the interpreter
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the calling convention to be used for the C function. It should normally always
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be ``METH_VARARGS`` or ``METH_VARARGS | METH_KEYWORDS``; a value of ``0`` means
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that an obsolete variant of :c:func:`PyArg_ParseTuple` is used.
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When using only ``METH_VARARGS``, the function should expect the Python-level
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parameters to be passed in as a tuple acceptable for parsing via
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:c:func:`PyArg_ParseTuple`; more information on this function is provided below.
|
2007-08-15 11:28:22 -03:00
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The :const:`METH_KEYWORDS` bit may be set in the third field if keyword
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arguments should be passed to the function. In this case, the C function should
|
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accept a third ``PyObject *`` parameter which will be a dictionary of keywords.
|
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Use :c:func:`PyArg_ParseTupleAndKeywords` to parse the arguments to such a
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2007-08-15 11:28:22 -03:00
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function.
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The method table must be referenced in the module definition structure::
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static struct PyModuleDef spammodule = {
|
2017-08-31 03:11:02 -03:00
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PyModuleDef_HEAD_INIT,
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"spam", /* name of module */
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spam_doc, /* module documentation, may be NULL */
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-1, /* size of per-interpreter state of the module,
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or -1 if the module keeps state in global variables. */
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SpamMethods
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};
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This structure, in turn, must be passed to the interpreter in the module's
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initialization function. The initialization function must be named
|
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:c:func:`PyInit_name`, where *name* is the name of the module, and should be the
|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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only non-\ ``static`` item defined in the module file::
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PyMODINIT_FUNC
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PyInit_spam(void)
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{
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return PyModule_Create(&spammodule);
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2007-08-15 11:28:22 -03:00
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}
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2008-12-24 12:27:25 -04:00
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Note that PyMODINIT_FUNC declares the function as ``PyObject *`` return type,
|
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declares any special linkage declarations required by the platform, and for C++
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2007-08-15 11:28:22 -03:00
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declares the function as ``extern "C"``.
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When the Python program imports module :mod:`spam` for the first time,
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:c:func:`PyInit_spam` is called. (See below for comments about embedding Python.)
|
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It calls :c:func:`PyModule_Create`, which returns a module object, and
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2007-08-15 11:28:22 -03:00
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inserts built-in function objects into the newly created module based upon the
|
2010-10-06 07:11:56 -03:00
|
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table (an array of :c:type:`PyMethodDef` structures) found in the module definition.
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:c:func:`PyModule_Create` returns a pointer to the module object
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2008-06-11 02:26:20 -03:00
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that it creates. It may abort with a fatal error for
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2007-08-15 11:28:22 -03:00
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certain errors, or return *NULL* if the module could not be initialized
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2008-06-11 02:26:20 -03:00
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satisfactorily. The init function must return the module object to its caller,
|
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|
so that it then gets inserted into ``sys.modules``.
|
2007-08-15 11:28:22 -03:00
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|
2010-10-06 07:11:56 -03:00
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When embedding Python, the :c:func:`PyInit_spam` function is not called
|
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|
automatically unless there's an entry in the :c:data:`PyImport_Inittab` table.
|
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|
To add the module to the initialization table, use :c:func:`PyImport_AppendInittab`,
|
2008-06-11 02:26:20 -03:00
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|
optionally followed by an import of the module::
|
2007-08-15 11:28:22 -03:00
|
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|
int
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main(int argc, char *argv[])
|
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|
|
{
|
2014-08-01 07:28:49 -03:00
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|
wchar_t *program = Py_DecodeLocale(argv[0], NULL);
|
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|
|
if (program == NULL) {
|
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|
fprintf(stderr, "Fatal error: cannot decode argv[0]\n");
|
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|
exit(1);
|
|
|
|
}
|
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|
|
2010-02-06 14:46:57 -04:00
|
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|
/* Add a built-in module, before Py_Initialize */
|
2008-06-11 02:26:20 -03:00
|
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|
PyImport_AppendInittab("spam", PyInit_spam);
|
|
|
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|
2007-08-15 11:28:22 -03:00
|
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/* Pass argv[0] to the Python interpreter */
|
2014-08-01 07:28:49 -03:00
|
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|
Py_SetProgramName(program);
|
2007-08-15 11:28:22 -03:00
|
|
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|
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|
|
/* Initialize the Python interpreter. Required. */
|
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|
|
Py_Initialize();
|
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|
|
|
2008-06-11 02:26:20 -03:00
|
|
|
/* Optionally import the module; alternatively,
|
|
|
|
import can be deferred until the embedded script
|
|
|
|
imports it. */
|
|
|
|
PyImport_ImportModule("spam");
|
2007-08-15 11:28:22 -03:00
|
|
|
|
2013-10-06 08:14:10 -03:00
|
|
|
...
|
|
|
|
|
2014-08-01 07:28:49 -03:00
|
|
|
PyMem_RawFree(program);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2007-08-15 11:28:22 -03:00
|
|
|
.. note::
|
|
|
|
|
|
|
|
Removing entries from ``sys.modules`` or importing compiled modules into
|
2010-10-06 07:11:56 -03:00
|
|
|
multiple interpreters within a process (or following a :c:func:`fork` without an
|
|
|
|
intervening :c:func:`exec`) can create problems for some extension modules.
|
2007-08-15 11:28:22 -03:00
|
|
|
Extension module authors should exercise caution when initializing internal data
|
|
|
|
structures.
|
|
|
|
|
|
|
|
A more substantial example module is included in the Python source distribution
|
|
|
|
as :file:`Modules/xxmodule.c`. This file may be used as a template or simply
|
Merged revisions 78338,78345-78346,78561-78562,78566,78574,78581,78634,78660,78675 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r78338 | andrew.kuchling | 2010-02-22 15:04:02 -0600 (Mon, 22 Feb 2010) | 4 lines
Remove Tools/modulator, a reference to it in the docs, and a screenshot of it.
(I asked the BDFL first, and he approved removing it. The last actual bugfix
to Tools/modulator was in 2001; since then all changes have been search-and-replace:
string methods, whitespace fixes, etc.)
........
r78345 | andrew.kuchling | 2010-02-22 17:10:52 -0600 (Mon, 22 Feb 2010) | 1 line
#7706: DONT_HAVE_ERRNO_H is no longer defined by configure (after rev.46819).
........
r78346 | andrew.kuchling | 2010-02-22 17:12:00 -0600 (Mon, 22 Feb 2010) | 1 line
#7706: add include guards where they're missing; required for Windows CE
........
r78561 | andrew.kuchling | 2010-03-01 13:51:43 -0600 (Mon, 01 Mar 2010) | 1 line
#7191: describe more details of wbits parameter
........
r78562 | andrew.kuchling | 2010-03-01 14:11:57 -0600 (Mon, 01 Mar 2010) | 1 line
#7637: avoid repeated-concatenation antipattern in example
........
r78566 | barry.warsaw | 2010-03-01 15:46:51 -0600 (Mon, 01 Mar 2010) | 4 lines
Manually copy patch for bug 7250 from the release26-maint branch. I suck
because I did this in the wrong order and couldn't smack svnmerge into
submission.
........
r78574 | benjamin.peterson | 2010-03-01 17:25:13 -0600 (Mon, 01 Mar 2010) | 1 line
remove CVS id
........
r78581 | michael.foord | 2010-03-02 08:22:15 -0600 (Tue, 02 Mar 2010) | 1 line
Link correction in documentation.
........
r78634 | benjamin.peterson | 2010-03-03 15:28:25 -0600 (Wed, 03 Mar 2010) | 1 line
rephrase
........
r78660 | dirkjan.ochtman | 2010-03-04 13:21:53 -0600 (Thu, 04 Mar 2010) | 4 lines
Try to fix buildbot breakage from r78384.
Thanks bitdancer and briancurtin for the help.
........
r78675 | florent.xicluna | 2010-03-04 19:12:14 -0600 (Thu, 04 Mar 2010) | 2 lines
These line should not be there.
........
2010-03-21 19:36:19 -03:00
|
|
|
read as an example.
|
2007-08-15 11:28:22 -03:00
|
|
|
|
2015-07-03 06:49:15 -03:00
|
|
|
.. note::
|
|
|
|
|
|
|
|
Unlike our ``spam`` example, ``xxmodule`` uses *multi-phase initialization*
|
|
|
|
(new in Python 3.5), where a PyModuleDef structure is returned from
|
|
|
|
``PyInit_spam``, and creation of the module is left to the import machinery.
|
|
|
|
For details on multi-phase initialization, see :PEP:`489`.
|
|
|
|
|
2007-08-15 11:28:22 -03:00
|
|
|
|
|
|
|
.. _compilation:
|
|
|
|
|
|
|
|
Compilation and Linkage
|
|
|
|
=======================
|
|
|
|
|
|
|
|
There are two more things to do before you can use your new extension: compiling
|
|
|
|
and linking it with the Python system. If you use dynamic loading, the details
|
|
|
|
may depend on the style of dynamic loading your system uses; see the chapters
|
|
|
|
about building extension modules (chapter :ref:`building`) and additional
|
|
|
|
information that pertains only to building on Windows (chapter
|
|
|
|
:ref:`building-on-windows`) for more information about this.
|
|
|
|
|
|
|
|
If you can't use dynamic loading, or if you want to make your module a permanent
|
|
|
|
part of the Python interpreter, you will have to change the configuration setup
|
|
|
|
and rebuild the interpreter. Luckily, this is very simple on Unix: just place
|
|
|
|
your file (:file:`spammodule.c` for example) in the :file:`Modules/` directory
|
|
|
|
of an unpacked source distribution, add a line to the file
|
|
|
|
:file:`Modules/Setup.local` describing your file::
|
|
|
|
|
|
|
|
spam spammodule.o
|
|
|
|
|
|
|
|
and rebuild the interpreter by running :program:`make` in the toplevel
|
|
|
|
directory. You can also run :program:`make` in the :file:`Modules/`
|
|
|
|
subdirectory, but then you must first rebuild :file:`Makefile` there by running
|
|
|
|
':program:`make` Makefile'. (This is necessary each time you change the
|
|
|
|
:file:`Setup` file.)
|
|
|
|
|
|
|
|
If your module requires additional libraries to link with, these can be listed
|
|
|
|
on the line in the configuration file as well, for instance::
|
|
|
|
|
|
|
|
spam spammodule.o -lX11
|
|
|
|
|
|
|
|
|
|
|
|
.. _callingpython:
|
|
|
|
|
|
|
|
Calling Python Functions from C
|
|
|
|
===============================
|
|
|
|
|
|
|
|
So far we have concentrated on making C functions callable from Python. The
|
|
|
|
reverse is also useful: calling Python functions from C. This is especially the
|
|
|
|
case for libraries that support so-called "callback" functions. If a C
|
|
|
|
interface makes use of callbacks, the equivalent Python often needs to provide a
|
|
|
|
callback mechanism to the Python programmer; the implementation will require
|
|
|
|
calling the Python callback functions from a C callback. Other uses are also
|
|
|
|
imaginable.
|
|
|
|
|
|
|
|
Fortunately, the Python interpreter is easily called recursively, and there is a
|
|
|
|
standard interface to call a Python function. (I won't dwell on how to call the
|
|
|
|
Python parser with a particular string as input --- if you're interested, have a
|
|
|
|
look at the implementation of the :option:`-c` command line option in
|
2007-09-06 11:49:02 -03:00
|
|
|
:file:`Modules/main.c` from the Python source code.)
|
2007-08-15 11:28:22 -03:00
|
|
|
|
|
|
|
Calling a Python function is easy. First, the Python program must somehow pass
|
|
|
|
you the Python function object. You should provide a function (or some other
|
|
|
|
interface) to do this. When this function is called, save a pointer to the
|
2010-10-06 07:11:56 -03:00
|
|
|
Python function object (be careful to :c:func:`Py_INCREF` it!) in a global
|
2007-08-15 11:28:22 -03:00
|
|
|
variable --- or wherever you see fit. For example, the following function might
|
|
|
|
be part of a module definition::
|
|
|
|
|
|
|
|
static PyObject *my_callback = NULL;
|
|
|
|
|
|
|
|
static PyObject *
|
|
|
|
my_set_callback(PyObject *dummy, PyObject *args)
|
|
|
|
{
|
|
|
|
PyObject *result = NULL;
|
|
|
|
PyObject *temp;
|
|
|
|
|
|
|
|
if (PyArg_ParseTuple(args, "O:set_callback", &temp)) {
|
|
|
|
if (!PyCallable_Check(temp)) {
|
|
|
|
PyErr_SetString(PyExc_TypeError, "parameter must be callable");
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
Py_XINCREF(temp); /* Add a reference to new callback */
|
|
|
|
Py_XDECREF(my_callback); /* Dispose of previous callback */
|
|
|
|
my_callback = temp; /* Remember new callback */
|
|
|
|
/* Boilerplate to return "None" */
|
|
|
|
Py_INCREF(Py_None);
|
|
|
|
result = Py_None;
|
|
|
|
}
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
This function must be registered with the interpreter using the
|
|
|
|
:const:`METH_VARARGS` flag; this is described in section :ref:`methodtable`. The
|
2010-10-06 07:11:56 -03:00
|
|
|
:c:func:`PyArg_ParseTuple` function and its arguments are documented in section
|
2007-08-15 11:28:22 -03:00
|
|
|
:ref:`parsetuple`.
|
|
|
|
|
2010-10-06 07:11:56 -03:00
|
|
|
The macros :c:func:`Py_XINCREF` and :c:func:`Py_XDECREF` increment/decrement the
|
2007-08-15 11:28:22 -03:00
|
|
|
reference count of an object and are safe in the presence of *NULL* pointers
|
|
|
|
(but note that *temp* will not be *NULL* in this context). More info on them
|
|
|
|
in section :ref:`refcounts`.
|
|
|
|
|
Merged revisions 70712,70714,70764-70765,70769-70771,70773,70776-70777,70788-70789,70824,70828,70832,70836,70842,70851,70855,70857,70866-70872,70883,70885,70893-70894,70896-70897,70903,70905-70907,70915,70927,70933,70951,70960,70962-70964,70998,71001,71006,71008,71010-71011,71019,71037,71056,71094,71101-71103,71106,71119,71123,71149-71150,71203,71212,71214-71217,71221,71240 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r70712 | benjamin.peterson | 2009-03-30 10:15:38 -0500 (Mon, 30 Mar 2009) | 1 line
don't rely on the order dict repr #5605
........
r70714 | brett.cannon | 2009-03-30 10:20:53 -0500 (Mon, 30 Mar 2009) | 1 line
Add an entry to developers.txt.
........
r70764 | martin.v.loewis | 2009-03-30 17:06:33 -0500 (Mon, 30 Mar 2009) | 2 lines
Add several VM developers.
........
r70765 | georg.brandl | 2009-03-30 17:09:34 -0500 (Mon, 30 Mar 2009) | 1 line
#5199: make warning about vars() assignment more visible.
........
r70769 | andrew.kuchling | 2009-03-30 17:29:53 -0500 (Mon, 30 Mar 2009) | 1 line
Remove comment
........
r70770 | andrew.kuchling | 2009-03-30 17:30:20 -0500 (Mon, 30 Mar 2009) | 1 line
Add several items and placeholders
........
r70771 | andrew.kuchling | 2009-03-30 17:31:11 -0500 (Mon, 30 Mar 2009) | 1 line
Many edits
........
r70773 | georg.brandl | 2009-03-30 17:43:00 -0500 (Mon, 30 Mar 2009) | 1 line
#5039: make it clear that the impl. note refers to CPython.
........
r70776 | andrew.kuchling | 2009-03-30 18:08:24 -0500 (Mon, 30 Mar 2009) | 1 line
typo fix
........
r70777 | andrew.kuchling | 2009-03-30 18:09:46 -0500 (Mon, 30 Mar 2009) | 1 line
Add more items
........
r70788 | andrew.kuchling | 2009-03-30 20:21:01 -0500 (Mon, 30 Mar 2009) | 1 line
Add various items
........
r70789 | georg.brandl | 2009-03-30 20:25:15 -0500 (Mon, 30 Mar 2009) | 1 line
Fix a wrong struct field assignment (docstring as closure).
........
r70824 | georg.brandl | 2009-03-31 10:43:20 -0500 (Tue, 31 Mar 2009) | 1 line
#5519: remove reference to Kodos, which seems dead.
........
r70828 | georg.brandl | 2009-03-31 10:50:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5581: fget argument of abstractproperty is optional as well.
........
r70832 | georg.brandl | 2009-03-31 11:31:11 -0500 (Tue, 31 Mar 2009) | 1 line
#1386675: specify WindowsError as the exception, because it has a winerror attribute that EnvironmentError doesnt have.
........
r70836 | georg.brandl | 2009-03-31 11:50:25 -0500 (Tue, 31 Mar 2009) | 1 line
#5417: replace references to undocumented functions by ones to documented functions.
........
r70842 | georg.brandl | 2009-03-31 12:13:06 -0500 (Tue, 31 Mar 2009) | 1 line
#970783: document PyObject_Generic[GS]etAttr.
........
r70851 | georg.brandl | 2009-03-31 13:26:55 -0500 (Tue, 31 Mar 2009) | 1 line
#837577: note cryptic return value of spawn*e on invalid env dicts.
........
r70855 | georg.brandl | 2009-03-31 13:30:37 -0500 (Tue, 31 Mar 2009) | 1 line
#5245: note that PyRun_SimpleString doesnt return on SystemExit.
........
r70857 | georg.brandl | 2009-03-31 13:33:10 -0500 (Tue, 31 Mar 2009) | 1 line
#5227: note that Py_Main doesnt return on SystemExit.
........
r70866 | georg.brandl | 2009-03-31 14:06:57 -0500 (Tue, 31 Mar 2009) | 1 line
#4882: document named group behavior a bit better.
........
r70867 | georg.brandl | 2009-03-31 14:10:35 -0500 (Tue, 31 Mar 2009) | 1 line
#1096310: document usage of sys.__std*__ a bit better.
........
r70868 | georg.brandl | 2009-03-31 14:12:17 -0500 (Tue, 31 Mar 2009) | 1 line
#5190: export make_option in __all__.
........
r70869 | georg.brandl | 2009-03-31 14:14:42 -0500 (Tue, 31 Mar 2009) | 1 line
Fix-up unwanted change.
........
r70870 | georg.brandl | 2009-03-31 14:26:24 -0500 (Tue, 31 Mar 2009) | 1 line
#4411: document mro() and __mro__. (I hope I got it right.)
........
r70871 | georg.brandl | 2009-03-31 14:30:56 -0500 (Tue, 31 Mar 2009) | 1 line
#5618: fix typo.
........
r70872 | r.david.murray | 2009-03-31 14:31:17 -0500 (Tue, 31 Mar 2009) | 3 lines
Delete out-of-date and little-known README from the test
directory by consensus of devs at pycon sprint.
........
r70883 | georg.brandl | 2009-03-31 15:41:08 -0500 (Tue, 31 Mar 2009) | 1 line
#1674032: return value of flag from Event.wait(). OKed by Guido.
........
r70885 | tarek.ziade | 2009-03-31 15:48:31 -0500 (Tue, 31 Mar 2009) | 1 line
using log.warn for sys.stderr
........
r70893 | georg.brandl | 2009-03-31 15:56:32 -0500 (Tue, 31 Mar 2009) | 1 line
#1530012: move TQS section before raw strings.
........
r70894 | benjamin.peterson | 2009-03-31 16:06:30 -0500 (Tue, 31 Mar 2009) | 1 line
take the usual lock precautions around _active_limbo_lock
........
r70896 | georg.brandl | 2009-03-31 16:15:33 -0500 (Tue, 31 Mar 2009) | 1 line
#5598: document DocFileSuite *args argument.
........
r70897 | benjamin.peterson | 2009-03-31 16:34:42 -0500 (Tue, 31 Mar 2009) | 1 line
fix Thread.ident when it is the main thread or a dummy thread #5632
........
r70903 | georg.brandl | 2009-03-31 16:45:18 -0500 (Tue, 31 Mar 2009) | 1 line
#1676135: remove trailing slashes from --prefix argument.
........
r70905 | georg.brandl | 2009-03-31 17:03:40 -0500 (Tue, 31 Mar 2009) | 1 line
#5563: more documentation for bdist_msi.
........
r70906 | georg.brandl | 2009-03-31 17:11:53 -0500 (Tue, 31 Mar 2009) | 1 line
#1651995: fix _convert_ref for non-ASCII characters.
........
r70907 | georg.brandl | 2009-03-31 17:18:19 -0500 (Tue, 31 Mar 2009) | 1 line
#3427: document correct return type for urlopen().info().
........
r70915 | georg.brandl | 2009-03-31 17:40:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5018: remove confusing paragraph.
........
r70927 | georg.brandl | 2009-03-31 18:01:27 -0500 (Tue, 31 Mar 2009) | 1 line
Dont shout to users.
........
r70933 | georg.brandl | 2009-03-31 19:04:33 -0500 (Tue, 31 Mar 2009) | 2 lines
Issue #5635: Fix running test_sys with tracing enabled.
........
r70951 | georg.brandl | 2009-04-01 09:02:27 -0500 (Wed, 01 Apr 2009) | 1 line
Add Maksim, who worked on several issues at the sprint.
........
r70960 | jesse.noller | 2009-04-01 11:42:19 -0500 (Wed, 01 Apr 2009) | 1 line
Issue 3270: document Listener address restrictions on windows
........
r70962 | brett.cannon | 2009-04-01 12:07:16 -0500 (Wed, 01 Apr 2009) | 2 lines
Ron DuPlain was given commit privileges at PyCon 2009 to work on 3to2.
........
r70963 | georg.brandl | 2009-04-01 12:46:01 -0500 (Wed, 01 Apr 2009) | 1 line
#5655: fix docstring oversight.
........
r70964 | brett.cannon | 2009-04-01 12:52:13 -0500 (Wed, 01 Apr 2009) | 2 lines
Paul Kippes was given commit privileges to work on 3to2.
........
r70998 | georg.brandl | 2009-04-01 16:54:21 -0500 (Wed, 01 Apr 2009) | 1 line
In Pdb, stop assigning values to __builtin__._ which interferes with the one commonly installed by gettext.
........
r71001 | brett.cannon | 2009-04-01 18:01:12 -0500 (Wed, 01 Apr 2009) | 3 lines
Add my initials to Misc/developers.txt. Names are now sorted by number of
characters in the person's name.
........
r71006 | georg.brandl | 2009-04-01 18:32:17 -0500 (Wed, 01 Apr 2009) | 1 line
Cache the f_locals dict of the current frame, since every access to frame.f_locals overrides its contents with the real locals which undoes modifications made by the debugging user.
........
r71008 | andrew.kuchling | 2009-04-01 19:02:14 -0500 (Wed, 01 Apr 2009) | 1 line
Typo fix
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r71010 | benjamin.peterson | 2009-04-01 19:11:52 -0500 (Wed, 01 Apr 2009) | 1 line
fix markup
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r71011 | benjamin.peterson | 2009-04-01 19:12:47 -0500 (Wed, 01 Apr 2009) | 1 line
this should be :noindex:
........
r71019 | georg.brandl | 2009-04-01 21:00:01 -0500 (Wed, 01 Apr 2009) | 1 line
Fix test_doctest, missed two assignments to curframe.
........
r71037 | r.david.murray | 2009-04-01 23:34:04 -0500 (Wed, 01 Apr 2009) | 6 lines
Clarify that datetime strftime does not produce leap seconds and datetime
strptime does not accept it in the strftime behavior section of the
datetime docs.
Closes issue 2568.
........
r71056 | georg.brandl | 2009-04-02 12:43:07 -0500 (Thu, 02 Apr 2009) | 2 lines
Actually the displayhook should print the repr.
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r71094 | vinay.sajip | 2009-04-03 05:23:18 -0500 (Fri, 03 Apr 2009) | 1 line
Added warning about logging use from asynchronous signal handlers.
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r71101 | andrew.kuchling | 2009-04-03 16:43:00 -0500 (Fri, 03 Apr 2009) | 1 line
Add some items
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r71102 | andrew.kuchling | 2009-04-03 16:44:49 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the'; grammar fix
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r71103 | andrew.kuchling | 2009-04-03 16:45:29 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the' duplication
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r71106 | vinay.sajip | 2009-04-03 16:58:16 -0500 (Fri, 03 Apr 2009) | 1 line
Clarified warning about logging use from asynchronous signal handlers.
........
r71119 | raymond.hettinger | 2009-04-04 00:37:47 -0500 (Sat, 04 Apr 2009) | 1 line
Add helpful link.
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r71123 | r.david.murray | 2009-04-04 01:39:56 -0500 (Sat, 04 Apr 2009) | 2 lines
Fix error in description of 'oct' (issue 5678).
........
r71149 | georg.brandl | 2009-04-04 08:42:39 -0500 (Sat, 04 Apr 2009) | 1 line
#5642: clarify map() compatibility to the builtin.
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r71150 | georg.brandl | 2009-04-04 08:45:49 -0500 (Sat, 04 Apr 2009) | 1 line
#5601: clarify that webbrowser is not meant for file names.
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r71203 | benjamin.peterson | 2009-04-04 18:46:34 -0500 (Sat, 04 Apr 2009) | 1 line
note how using iter* are unsafe while mutating and document iter(dict)
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r71212 | georg.brandl | 2009-04-05 05:24:20 -0500 (Sun, 05 Apr 2009) | 1 line
#1742837: expand HTTP server docs, and fix SocketServer ones to document methods as methods, not functions.
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r71214 | georg.brandl | 2009-04-05 05:29:57 -0500 (Sun, 05 Apr 2009) | 1 line
Normalize spelling of Mac OS X.
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r71215 | georg.brandl | 2009-04-05 05:32:26 -0500 (Sun, 05 Apr 2009) | 1 line
Avoid sure signs of a diseased mind.
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r71216 | georg.brandl | 2009-04-05 05:41:02 -0500 (Sun, 05 Apr 2009) | 1 line
#1718017: document the relation of os.path and the posixpath, ntpath etc. modules better.
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r71217 | georg.brandl | 2009-04-05 05:48:47 -0500 (Sun, 05 Apr 2009) | 1 line
#1726172: dont raise an unexpected IndexError if a voidresp() call has an empty response.
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r71221 | vinay.sajip | 2009-04-05 06:06:24 -0500 (Sun, 05 Apr 2009) | 1 line
Issue #5695: Moved logging.captureWarnings() call inside with statement in WarningsTest.test_warnings.
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r71240 | georg.brandl | 2009-04-05 09:40:06 -0500 (Sun, 05 Apr 2009) | 1 line
#5370: doc update about unpickling objects with custom __getattr__ etc. methods.
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2009-04-05 16:13:16 -03:00
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.. index:: single: PyObject_CallObject()
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2007-08-15 11:28:22 -03:00
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Later, when it is time to call the function, you call the C function
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2010-10-06 07:11:56 -03:00
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:c:func:`PyObject_CallObject`. This function has two arguments, both pointers to
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2007-08-15 11:28:22 -03:00
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arbitrary Python objects: the Python function, and the argument list. The
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argument list must always be a tuple object, whose length is the number of
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2009-01-03 17:18:54 -04:00
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arguments. To call the Python function with no arguments, pass in NULL, or
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Merged revisions 59259-59274 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
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r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines
Issue #1531: Read fileobj from the current offset, do not seek to
the start.
(will backport to 2.5)
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r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines
Document PyEval_* functions from ceval.c.
Credits to Michael Sloan from GHOP.
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r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines
Add a few refcount data entries.
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r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines
Add test suite for cmd module.
Written by Michael Schneider for GHOP.
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r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines
Add examples to the ElementTree documentation.
Written by h4wk.cz for GHOP.
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r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines
Add "Using Python on Windows" document, by Robert Lehmann.
Written for GHOP.
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r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines
Add example to mmap docs.
Written for GHOP by Rafal Rawicki.
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r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines
Convert bdb.rst line endings to Unix style.
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r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines
Add more entries to the glossary.
Written by Jeff Wheeler for GHOP.
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2007-12-02 11:22:16 -04:00
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an empty tuple; to call it with one argument, pass a singleton tuple.
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2010-10-06 07:11:56 -03:00
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:c:func:`Py_BuildValue` returns a tuple when its format string consists of zero
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Merged revisions 59259-59274 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines
Issue #1531: Read fileobj from the current offset, do not seek to
the start.
(will backport to 2.5)
........
r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines
Document PyEval_* functions from ceval.c.
Credits to Michael Sloan from GHOP.
........
r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines
Add a few refcount data entries.
........
r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines
Add test suite for cmd module.
Written by Michael Schneider for GHOP.
........
r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines
Add examples to the ElementTree documentation.
Written by h4wk.cz for GHOP.
........
r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines
Add "Using Python on Windows" document, by Robert Lehmann.
Written for GHOP.
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r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines
Add example to mmap docs.
Written for GHOP by Rafal Rawicki.
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r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines
Convert bdb.rst line endings to Unix style.
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r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines
Add more entries to the glossary.
Written by Jeff Wheeler for GHOP.
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2007-12-02 11:22:16 -04:00
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or more format codes between parentheses. For example::
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2007-08-15 11:28:22 -03:00
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int arg;
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PyObject *arglist;
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...
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arg = 123;
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...
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/* Time to call the callback */
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arglist = Py_BuildValue("(i)", arg);
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Merged revisions 70712,70714,70764-70765,70769-70771,70773,70776-70777,70788-70789,70824,70828,70832,70836,70842,70851,70855,70857,70866-70872,70883,70885,70893-70894,70896-70897,70903,70905-70907,70915,70927,70933,70951,70960,70962-70964,70998,71001,71006,71008,71010-71011,71019,71037,71056,71094,71101-71103,71106,71119,71123,71149-71150,71203,71212,71214-71217,71221,71240 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r70712 | benjamin.peterson | 2009-03-30 10:15:38 -0500 (Mon, 30 Mar 2009) | 1 line
don't rely on the order dict repr #5605
........
r70714 | brett.cannon | 2009-03-30 10:20:53 -0500 (Mon, 30 Mar 2009) | 1 line
Add an entry to developers.txt.
........
r70764 | martin.v.loewis | 2009-03-30 17:06:33 -0500 (Mon, 30 Mar 2009) | 2 lines
Add several VM developers.
........
r70765 | georg.brandl | 2009-03-30 17:09:34 -0500 (Mon, 30 Mar 2009) | 1 line
#5199: make warning about vars() assignment more visible.
........
r70769 | andrew.kuchling | 2009-03-30 17:29:53 -0500 (Mon, 30 Mar 2009) | 1 line
Remove comment
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r70770 | andrew.kuchling | 2009-03-30 17:30:20 -0500 (Mon, 30 Mar 2009) | 1 line
Add several items and placeholders
........
r70771 | andrew.kuchling | 2009-03-30 17:31:11 -0500 (Mon, 30 Mar 2009) | 1 line
Many edits
........
r70773 | georg.brandl | 2009-03-30 17:43:00 -0500 (Mon, 30 Mar 2009) | 1 line
#5039: make it clear that the impl. note refers to CPython.
........
r70776 | andrew.kuchling | 2009-03-30 18:08:24 -0500 (Mon, 30 Mar 2009) | 1 line
typo fix
........
r70777 | andrew.kuchling | 2009-03-30 18:09:46 -0500 (Mon, 30 Mar 2009) | 1 line
Add more items
........
r70788 | andrew.kuchling | 2009-03-30 20:21:01 -0500 (Mon, 30 Mar 2009) | 1 line
Add various items
........
r70789 | georg.brandl | 2009-03-30 20:25:15 -0500 (Mon, 30 Mar 2009) | 1 line
Fix a wrong struct field assignment (docstring as closure).
........
r70824 | georg.brandl | 2009-03-31 10:43:20 -0500 (Tue, 31 Mar 2009) | 1 line
#5519: remove reference to Kodos, which seems dead.
........
r70828 | georg.brandl | 2009-03-31 10:50:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5581: fget argument of abstractproperty is optional as well.
........
r70832 | georg.brandl | 2009-03-31 11:31:11 -0500 (Tue, 31 Mar 2009) | 1 line
#1386675: specify WindowsError as the exception, because it has a winerror attribute that EnvironmentError doesnt have.
........
r70836 | georg.brandl | 2009-03-31 11:50:25 -0500 (Tue, 31 Mar 2009) | 1 line
#5417: replace references to undocumented functions by ones to documented functions.
........
r70842 | georg.brandl | 2009-03-31 12:13:06 -0500 (Tue, 31 Mar 2009) | 1 line
#970783: document PyObject_Generic[GS]etAttr.
........
r70851 | georg.brandl | 2009-03-31 13:26:55 -0500 (Tue, 31 Mar 2009) | 1 line
#837577: note cryptic return value of spawn*e on invalid env dicts.
........
r70855 | georg.brandl | 2009-03-31 13:30:37 -0500 (Tue, 31 Mar 2009) | 1 line
#5245: note that PyRun_SimpleString doesnt return on SystemExit.
........
r70857 | georg.brandl | 2009-03-31 13:33:10 -0500 (Tue, 31 Mar 2009) | 1 line
#5227: note that Py_Main doesnt return on SystemExit.
........
r70866 | georg.brandl | 2009-03-31 14:06:57 -0500 (Tue, 31 Mar 2009) | 1 line
#4882: document named group behavior a bit better.
........
r70867 | georg.brandl | 2009-03-31 14:10:35 -0500 (Tue, 31 Mar 2009) | 1 line
#1096310: document usage of sys.__std*__ a bit better.
........
r70868 | georg.brandl | 2009-03-31 14:12:17 -0500 (Tue, 31 Mar 2009) | 1 line
#5190: export make_option in __all__.
........
r70869 | georg.brandl | 2009-03-31 14:14:42 -0500 (Tue, 31 Mar 2009) | 1 line
Fix-up unwanted change.
........
r70870 | georg.brandl | 2009-03-31 14:26:24 -0500 (Tue, 31 Mar 2009) | 1 line
#4411: document mro() and __mro__. (I hope I got it right.)
........
r70871 | georg.brandl | 2009-03-31 14:30:56 -0500 (Tue, 31 Mar 2009) | 1 line
#5618: fix typo.
........
r70872 | r.david.murray | 2009-03-31 14:31:17 -0500 (Tue, 31 Mar 2009) | 3 lines
Delete out-of-date and little-known README from the test
directory by consensus of devs at pycon sprint.
........
r70883 | georg.brandl | 2009-03-31 15:41:08 -0500 (Tue, 31 Mar 2009) | 1 line
#1674032: return value of flag from Event.wait(). OKed by Guido.
........
r70885 | tarek.ziade | 2009-03-31 15:48:31 -0500 (Tue, 31 Mar 2009) | 1 line
using log.warn for sys.stderr
........
r70893 | georg.brandl | 2009-03-31 15:56:32 -0500 (Tue, 31 Mar 2009) | 1 line
#1530012: move TQS section before raw strings.
........
r70894 | benjamin.peterson | 2009-03-31 16:06:30 -0500 (Tue, 31 Mar 2009) | 1 line
take the usual lock precautions around _active_limbo_lock
........
r70896 | georg.brandl | 2009-03-31 16:15:33 -0500 (Tue, 31 Mar 2009) | 1 line
#5598: document DocFileSuite *args argument.
........
r70897 | benjamin.peterson | 2009-03-31 16:34:42 -0500 (Tue, 31 Mar 2009) | 1 line
fix Thread.ident when it is the main thread or a dummy thread #5632
........
r70903 | georg.brandl | 2009-03-31 16:45:18 -0500 (Tue, 31 Mar 2009) | 1 line
#1676135: remove trailing slashes from --prefix argument.
........
r70905 | georg.brandl | 2009-03-31 17:03:40 -0500 (Tue, 31 Mar 2009) | 1 line
#5563: more documentation for bdist_msi.
........
r70906 | georg.brandl | 2009-03-31 17:11:53 -0500 (Tue, 31 Mar 2009) | 1 line
#1651995: fix _convert_ref for non-ASCII characters.
........
r70907 | georg.brandl | 2009-03-31 17:18:19 -0500 (Tue, 31 Mar 2009) | 1 line
#3427: document correct return type for urlopen().info().
........
r70915 | georg.brandl | 2009-03-31 17:40:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5018: remove confusing paragraph.
........
r70927 | georg.brandl | 2009-03-31 18:01:27 -0500 (Tue, 31 Mar 2009) | 1 line
Dont shout to users.
........
r70933 | georg.brandl | 2009-03-31 19:04:33 -0500 (Tue, 31 Mar 2009) | 2 lines
Issue #5635: Fix running test_sys with tracing enabled.
........
r70951 | georg.brandl | 2009-04-01 09:02:27 -0500 (Wed, 01 Apr 2009) | 1 line
Add Maksim, who worked on several issues at the sprint.
........
r70960 | jesse.noller | 2009-04-01 11:42:19 -0500 (Wed, 01 Apr 2009) | 1 line
Issue 3270: document Listener address restrictions on windows
........
r70962 | brett.cannon | 2009-04-01 12:07:16 -0500 (Wed, 01 Apr 2009) | 2 lines
Ron DuPlain was given commit privileges at PyCon 2009 to work on 3to2.
........
r70963 | georg.brandl | 2009-04-01 12:46:01 -0500 (Wed, 01 Apr 2009) | 1 line
#5655: fix docstring oversight.
........
r70964 | brett.cannon | 2009-04-01 12:52:13 -0500 (Wed, 01 Apr 2009) | 2 lines
Paul Kippes was given commit privileges to work on 3to2.
........
r70998 | georg.brandl | 2009-04-01 16:54:21 -0500 (Wed, 01 Apr 2009) | 1 line
In Pdb, stop assigning values to __builtin__._ which interferes with the one commonly installed by gettext.
........
r71001 | brett.cannon | 2009-04-01 18:01:12 -0500 (Wed, 01 Apr 2009) | 3 lines
Add my initials to Misc/developers.txt. Names are now sorted by number of
characters in the person's name.
........
r71006 | georg.brandl | 2009-04-01 18:32:17 -0500 (Wed, 01 Apr 2009) | 1 line
Cache the f_locals dict of the current frame, since every access to frame.f_locals overrides its contents with the real locals which undoes modifications made by the debugging user.
........
r71008 | andrew.kuchling | 2009-04-01 19:02:14 -0500 (Wed, 01 Apr 2009) | 1 line
Typo fix
........
r71010 | benjamin.peterson | 2009-04-01 19:11:52 -0500 (Wed, 01 Apr 2009) | 1 line
fix markup
........
r71011 | benjamin.peterson | 2009-04-01 19:12:47 -0500 (Wed, 01 Apr 2009) | 1 line
this should be :noindex:
........
r71019 | georg.brandl | 2009-04-01 21:00:01 -0500 (Wed, 01 Apr 2009) | 1 line
Fix test_doctest, missed two assignments to curframe.
........
r71037 | r.david.murray | 2009-04-01 23:34:04 -0500 (Wed, 01 Apr 2009) | 6 lines
Clarify that datetime strftime does not produce leap seconds and datetime
strptime does not accept it in the strftime behavior section of the
datetime docs.
Closes issue 2568.
........
r71056 | georg.brandl | 2009-04-02 12:43:07 -0500 (Thu, 02 Apr 2009) | 2 lines
Actually the displayhook should print the repr.
........
r71094 | vinay.sajip | 2009-04-03 05:23:18 -0500 (Fri, 03 Apr 2009) | 1 line
Added warning about logging use from asynchronous signal handlers.
........
r71101 | andrew.kuchling | 2009-04-03 16:43:00 -0500 (Fri, 03 Apr 2009) | 1 line
Add some items
........
r71102 | andrew.kuchling | 2009-04-03 16:44:49 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the'; grammar fix
........
r71103 | andrew.kuchling | 2009-04-03 16:45:29 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the' duplication
........
r71106 | vinay.sajip | 2009-04-03 16:58:16 -0500 (Fri, 03 Apr 2009) | 1 line
Clarified warning about logging use from asynchronous signal handlers.
........
r71119 | raymond.hettinger | 2009-04-04 00:37:47 -0500 (Sat, 04 Apr 2009) | 1 line
Add helpful link.
........
r71123 | r.david.murray | 2009-04-04 01:39:56 -0500 (Sat, 04 Apr 2009) | 2 lines
Fix error in description of 'oct' (issue 5678).
........
r71149 | georg.brandl | 2009-04-04 08:42:39 -0500 (Sat, 04 Apr 2009) | 1 line
#5642: clarify map() compatibility to the builtin.
........
r71150 | georg.brandl | 2009-04-04 08:45:49 -0500 (Sat, 04 Apr 2009) | 1 line
#5601: clarify that webbrowser is not meant for file names.
........
r71203 | benjamin.peterson | 2009-04-04 18:46:34 -0500 (Sat, 04 Apr 2009) | 1 line
note how using iter* are unsafe while mutating and document iter(dict)
........
r71212 | georg.brandl | 2009-04-05 05:24:20 -0500 (Sun, 05 Apr 2009) | 1 line
#1742837: expand HTTP server docs, and fix SocketServer ones to document methods as methods, not functions.
........
r71214 | georg.brandl | 2009-04-05 05:29:57 -0500 (Sun, 05 Apr 2009) | 1 line
Normalize spelling of Mac OS X.
........
r71215 | georg.brandl | 2009-04-05 05:32:26 -0500 (Sun, 05 Apr 2009) | 1 line
Avoid sure signs of a diseased mind.
........
r71216 | georg.brandl | 2009-04-05 05:41:02 -0500 (Sun, 05 Apr 2009) | 1 line
#1718017: document the relation of os.path and the posixpath, ntpath etc. modules better.
........
r71217 | georg.brandl | 2009-04-05 05:48:47 -0500 (Sun, 05 Apr 2009) | 1 line
#1726172: dont raise an unexpected IndexError if a voidresp() call has an empty response.
........
r71221 | vinay.sajip | 2009-04-05 06:06:24 -0500 (Sun, 05 Apr 2009) | 1 line
Issue #5695: Moved logging.captureWarnings() call inside with statement in WarningsTest.test_warnings.
........
r71240 | georg.brandl | 2009-04-05 09:40:06 -0500 (Sun, 05 Apr 2009) | 1 line
#5370: doc update about unpickling objects with custom __getattr__ etc. methods.
........
2009-04-05 16:13:16 -03:00
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result = PyObject_CallObject(my_callback, arglist);
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2007-08-15 11:28:22 -03:00
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Py_DECREF(arglist);
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2010-10-06 07:11:56 -03:00
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:c:func:`PyObject_CallObject` returns a Python object pointer: this is the return
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value of the Python function. :c:func:`PyObject_CallObject` is
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2007-08-15 11:28:22 -03:00
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"reference-count-neutral" with respect to its arguments. In the example a new
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2010-10-06 07:11:56 -03:00
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tuple was created to serve as the argument list, which is :c:func:`Py_DECREF`\
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-ed immediately after the :c:func:`PyObject_CallObject` call.
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2007-08-15 11:28:22 -03:00
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2010-10-06 07:11:56 -03:00
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The return value of :c:func:`PyObject_CallObject` is "new": either it is a brand
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2007-08-15 11:28:22 -03:00
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new object, or it is an existing object whose reference count has been
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incremented. So, unless you want to save it in a global variable, you should
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2010-10-06 07:11:56 -03:00
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somehow :c:func:`Py_DECREF` the result, even (especially!) if you are not
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2007-08-15 11:28:22 -03:00
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interested in its value.
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Before you do this, however, it is important to check that the return value
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isn't *NULL*. If it is, the Python function terminated by raising an exception.
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2010-10-06 07:11:56 -03:00
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If the C code that called :c:func:`PyObject_CallObject` is called from Python, it
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2007-08-15 11:28:22 -03:00
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should now return an error indication to its Python caller, so the interpreter
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can print a stack trace, or the calling Python code can handle the exception.
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If this is not possible or desirable, the exception should be cleared by calling
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2010-10-06 07:11:56 -03:00
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:c:func:`PyErr_Clear`. For example::
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2007-08-15 11:28:22 -03:00
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if (result == NULL)
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return NULL; /* Pass error back */
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...use result...
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2009-01-03 17:18:54 -04:00
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Py_DECREF(result);
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2007-08-15 11:28:22 -03:00
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Depending on the desired interface to the Python callback function, you may also
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2010-10-06 07:11:56 -03:00
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have to provide an argument list to :c:func:`PyObject_CallObject`. In some cases
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2007-08-15 11:28:22 -03:00
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the argument list is also provided by the Python program, through the same
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interface that specified the callback function. It can then be saved and used
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in the same manner as the function object. In other cases, you may have to
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construct a new tuple to pass as the argument list. The simplest way to do this
|
2010-10-06 07:11:56 -03:00
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is to call :c:func:`Py_BuildValue`. For example, if you want to pass an integral
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2007-08-15 11:28:22 -03:00
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event code, you might use the following code::
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PyObject *arglist;
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...
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arglist = Py_BuildValue("(l)", eventcode);
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Merged revisions 70712,70714,70764-70765,70769-70771,70773,70776-70777,70788-70789,70824,70828,70832,70836,70842,70851,70855,70857,70866-70872,70883,70885,70893-70894,70896-70897,70903,70905-70907,70915,70927,70933,70951,70960,70962-70964,70998,71001,71006,71008,71010-71011,71019,71037,71056,71094,71101-71103,71106,71119,71123,71149-71150,71203,71212,71214-71217,71221,71240 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r70712 | benjamin.peterson | 2009-03-30 10:15:38 -0500 (Mon, 30 Mar 2009) | 1 line
don't rely on the order dict repr #5605
........
r70714 | brett.cannon | 2009-03-30 10:20:53 -0500 (Mon, 30 Mar 2009) | 1 line
Add an entry to developers.txt.
........
r70764 | martin.v.loewis | 2009-03-30 17:06:33 -0500 (Mon, 30 Mar 2009) | 2 lines
Add several VM developers.
........
r70765 | georg.brandl | 2009-03-30 17:09:34 -0500 (Mon, 30 Mar 2009) | 1 line
#5199: make warning about vars() assignment more visible.
........
r70769 | andrew.kuchling | 2009-03-30 17:29:53 -0500 (Mon, 30 Mar 2009) | 1 line
Remove comment
........
r70770 | andrew.kuchling | 2009-03-30 17:30:20 -0500 (Mon, 30 Mar 2009) | 1 line
Add several items and placeholders
........
r70771 | andrew.kuchling | 2009-03-30 17:31:11 -0500 (Mon, 30 Mar 2009) | 1 line
Many edits
........
r70773 | georg.brandl | 2009-03-30 17:43:00 -0500 (Mon, 30 Mar 2009) | 1 line
#5039: make it clear that the impl. note refers to CPython.
........
r70776 | andrew.kuchling | 2009-03-30 18:08:24 -0500 (Mon, 30 Mar 2009) | 1 line
typo fix
........
r70777 | andrew.kuchling | 2009-03-30 18:09:46 -0500 (Mon, 30 Mar 2009) | 1 line
Add more items
........
r70788 | andrew.kuchling | 2009-03-30 20:21:01 -0500 (Mon, 30 Mar 2009) | 1 line
Add various items
........
r70789 | georg.brandl | 2009-03-30 20:25:15 -0500 (Mon, 30 Mar 2009) | 1 line
Fix a wrong struct field assignment (docstring as closure).
........
r70824 | georg.brandl | 2009-03-31 10:43:20 -0500 (Tue, 31 Mar 2009) | 1 line
#5519: remove reference to Kodos, which seems dead.
........
r70828 | georg.brandl | 2009-03-31 10:50:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5581: fget argument of abstractproperty is optional as well.
........
r70832 | georg.brandl | 2009-03-31 11:31:11 -0500 (Tue, 31 Mar 2009) | 1 line
#1386675: specify WindowsError as the exception, because it has a winerror attribute that EnvironmentError doesnt have.
........
r70836 | georg.brandl | 2009-03-31 11:50:25 -0500 (Tue, 31 Mar 2009) | 1 line
#5417: replace references to undocumented functions by ones to documented functions.
........
r70842 | georg.brandl | 2009-03-31 12:13:06 -0500 (Tue, 31 Mar 2009) | 1 line
#970783: document PyObject_Generic[GS]etAttr.
........
r70851 | georg.brandl | 2009-03-31 13:26:55 -0500 (Tue, 31 Mar 2009) | 1 line
#837577: note cryptic return value of spawn*e on invalid env dicts.
........
r70855 | georg.brandl | 2009-03-31 13:30:37 -0500 (Tue, 31 Mar 2009) | 1 line
#5245: note that PyRun_SimpleString doesnt return on SystemExit.
........
r70857 | georg.brandl | 2009-03-31 13:33:10 -0500 (Tue, 31 Mar 2009) | 1 line
#5227: note that Py_Main doesnt return on SystemExit.
........
r70866 | georg.brandl | 2009-03-31 14:06:57 -0500 (Tue, 31 Mar 2009) | 1 line
#4882: document named group behavior a bit better.
........
r70867 | georg.brandl | 2009-03-31 14:10:35 -0500 (Tue, 31 Mar 2009) | 1 line
#1096310: document usage of sys.__std*__ a bit better.
........
r70868 | georg.brandl | 2009-03-31 14:12:17 -0500 (Tue, 31 Mar 2009) | 1 line
#5190: export make_option in __all__.
........
r70869 | georg.brandl | 2009-03-31 14:14:42 -0500 (Tue, 31 Mar 2009) | 1 line
Fix-up unwanted change.
........
r70870 | georg.brandl | 2009-03-31 14:26:24 -0500 (Tue, 31 Mar 2009) | 1 line
#4411: document mro() and __mro__. (I hope I got it right.)
........
r70871 | georg.brandl | 2009-03-31 14:30:56 -0500 (Tue, 31 Mar 2009) | 1 line
#5618: fix typo.
........
r70872 | r.david.murray | 2009-03-31 14:31:17 -0500 (Tue, 31 Mar 2009) | 3 lines
Delete out-of-date and little-known README from the test
directory by consensus of devs at pycon sprint.
........
r70883 | georg.brandl | 2009-03-31 15:41:08 -0500 (Tue, 31 Mar 2009) | 1 line
#1674032: return value of flag from Event.wait(). OKed by Guido.
........
r70885 | tarek.ziade | 2009-03-31 15:48:31 -0500 (Tue, 31 Mar 2009) | 1 line
using log.warn for sys.stderr
........
r70893 | georg.brandl | 2009-03-31 15:56:32 -0500 (Tue, 31 Mar 2009) | 1 line
#1530012: move TQS section before raw strings.
........
r70894 | benjamin.peterson | 2009-03-31 16:06:30 -0500 (Tue, 31 Mar 2009) | 1 line
take the usual lock precautions around _active_limbo_lock
........
r70896 | georg.brandl | 2009-03-31 16:15:33 -0500 (Tue, 31 Mar 2009) | 1 line
#5598: document DocFileSuite *args argument.
........
r70897 | benjamin.peterson | 2009-03-31 16:34:42 -0500 (Tue, 31 Mar 2009) | 1 line
fix Thread.ident when it is the main thread or a dummy thread #5632
........
r70903 | georg.brandl | 2009-03-31 16:45:18 -0500 (Tue, 31 Mar 2009) | 1 line
#1676135: remove trailing slashes from --prefix argument.
........
r70905 | georg.brandl | 2009-03-31 17:03:40 -0500 (Tue, 31 Mar 2009) | 1 line
#5563: more documentation for bdist_msi.
........
r70906 | georg.brandl | 2009-03-31 17:11:53 -0500 (Tue, 31 Mar 2009) | 1 line
#1651995: fix _convert_ref for non-ASCII characters.
........
r70907 | georg.brandl | 2009-03-31 17:18:19 -0500 (Tue, 31 Mar 2009) | 1 line
#3427: document correct return type for urlopen().info().
........
r70915 | georg.brandl | 2009-03-31 17:40:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5018: remove confusing paragraph.
........
r70927 | georg.brandl | 2009-03-31 18:01:27 -0500 (Tue, 31 Mar 2009) | 1 line
Dont shout to users.
........
r70933 | georg.brandl | 2009-03-31 19:04:33 -0500 (Tue, 31 Mar 2009) | 2 lines
Issue #5635: Fix running test_sys with tracing enabled.
........
r70951 | georg.brandl | 2009-04-01 09:02:27 -0500 (Wed, 01 Apr 2009) | 1 line
Add Maksim, who worked on several issues at the sprint.
........
r70960 | jesse.noller | 2009-04-01 11:42:19 -0500 (Wed, 01 Apr 2009) | 1 line
Issue 3270: document Listener address restrictions on windows
........
r70962 | brett.cannon | 2009-04-01 12:07:16 -0500 (Wed, 01 Apr 2009) | 2 lines
Ron DuPlain was given commit privileges at PyCon 2009 to work on 3to2.
........
r70963 | georg.brandl | 2009-04-01 12:46:01 -0500 (Wed, 01 Apr 2009) | 1 line
#5655: fix docstring oversight.
........
r70964 | brett.cannon | 2009-04-01 12:52:13 -0500 (Wed, 01 Apr 2009) | 2 lines
Paul Kippes was given commit privileges to work on 3to2.
........
r70998 | georg.brandl | 2009-04-01 16:54:21 -0500 (Wed, 01 Apr 2009) | 1 line
In Pdb, stop assigning values to __builtin__._ which interferes with the one commonly installed by gettext.
........
r71001 | brett.cannon | 2009-04-01 18:01:12 -0500 (Wed, 01 Apr 2009) | 3 lines
Add my initials to Misc/developers.txt. Names are now sorted by number of
characters in the person's name.
........
r71006 | georg.brandl | 2009-04-01 18:32:17 -0500 (Wed, 01 Apr 2009) | 1 line
Cache the f_locals dict of the current frame, since every access to frame.f_locals overrides its contents with the real locals which undoes modifications made by the debugging user.
........
r71008 | andrew.kuchling | 2009-04-01 19:02:14 -0500 (Wed, 01 Apr 2009) | 1 line
Typo fix
........
r71010 | benjamin.peterson | 2009-04-01 19:11:52 -0500 (Wed, 01 Apr 2009) | 1 line
fix markup
........
r71011 | benjamin.peterson | 2009-04-01 19:12:47 -0500 (Wed, 01 Apr 2009) | 1 line
this should be :noindex:
........
r71019 | georg.brandl | 2009-04-01 21:00:01 -0500 (Wed, 01 Apr 2009) | 1 line
Fix test_doctest, missed two assignments to curframe.
........
r71037 | r.david.murray | 2009-04-01 23:34:04 -0500 (Wed, 01 Apr 2009) | 6 lines
Clarify that datetime strftime does not produce leap seconds and datetime
strptime does not accept it in the strftime behavior section of the
datetime docs.
Closes issue 2568.
........
r71056 | georg.brandl | 2009-04-02 12:43:07 -0500 (Thu, 02 Apr 2009) | 2 lines
Actually the displayhook should print the repr.
........
r71094 | vinay.sajip | 2009-04-03 05:23:18 -0500 (Fri, 03 Apr 2009) | 1 line
Added warning about logging use from asynchronous signal handlers.
........
r71101 | andrew.kuchling | 2009-04-03 16:43:00 -0500 (Fri, 03 Apr 2009) | 1 line
Add some items
........
r71102 | andrew.kuchling | 2009-04-03 16:44:49 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the'; grammar fix
........
r71103 | andrew.kuchling | 2009-04-03 16:45:29 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the' duplication
........
r71106 | vinay.sajip | 2009-04-03 16:58:16 -0500 (Fri, 03 Apr 2009) | 1 line
Clarified warning about logging use from asynchronous signal handlers.
........
r71119 | raymond.hettinger | 2009-04-04 00:37:47 -0500 (Sat, 04 Apr 2009) | 1 line
Add helpful link.
........
r71123 | r.david.murray | 2009-04-04 01:39:56 -0500 (Sat, 04 Apr 2009) | 2 lines
Fix error in description of 'oct' (issue 5678).
........
r71149 | georg.brandl | 2009-04-04 08:42:39 -0500 (Sat, 04 Apr 2009) | 1 line
#5642: clarify map() compatibility to the builtin.
........
r71150 | georg.brandl | 2009-04-04 08:45:49 -0500 (Sat, 04 Apr 2009) | 1 line
#5601: clarify that webbrowser is not meant for file names.
........
r71203 | benjamin.peterson | 2009-04-04 18:46:34 -0500 (Sat, 04 Apr 2009) | 1 line
note how using iter* are unsafe while mutating and document iter(dict)
........
r71212 | georg.brandl | 2009-04-05 05:24:20 -0500 (Sun, 05 Apr 2009) | 1 line
#1742837: expand HTTP server docs, and fix SocketServer ones to document methods as methods, not functions.
........
r71214 | georg.brandl | 2009-04-05 05:29:57 -0500 (Sun, 05 Apr 2009) | 1 line
Normalize spelling of Mac OS X.
........
r71215 | georg.brandl | 2009-04-05 05:32:26 -0500 (Sun, 05 Apr 2009) | 1 line
Avoid sure signs of a diseased mind.
........
r71216 | georg.brandl | 2009-04-05 05:41:02 -0500 (Sun, 05 Apr 2009) | 1 line
#1718017: document the relation of os.path and the posixpath, ntpath etc. modules better.
........
r71217 | georg.brandl | 2009-04-05 05:48:47 -0500 (Sun, 05 Apr 2009) | 1 line
#1726172: dont raise an unexpected IndexError if a voidresp() call has an empty response.
........
r71221 | vinay.sajip | 2009-04-05 06:06:24 -0500 (Sun, 05 Apr 2009) | 1 line
Issue #5695: Moved logging.captureWarnings() call inside with statement in WarningsTest.test_warnings.
........
r71240 | georg.brandl | 2009-04-05 09:40:06 -0500 (Sun, 05 Apr 2009) | 1 line
#5370: doc update about unpickling objects with custom __getattr__ etc. methods.
........
2009-04-05 16:13:16 -03:00
|
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|
result = PyObject_CallObject(my_callback, arglist);
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2007-08-15 11:28:22 -03:00
|
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Py_DECREF(arglist);
|
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if (result == NULL)
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|
return NULL; /* Pass error back */
|
|
|
|
/* Here maybe use the result */
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Py_DECREF(result);
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|
|
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Note the placement of ``Py_DECREF(arglist)`` immediately after the call, before
|
Merged revisions 59259-59274 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines
Issue #1531: Read fileobj from the current offset, do not seek to
the start.
(will backport to 2.5)
........
r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines
Document PyEval_* functions from ceval.c.
Credits to Michael Sloan from GHOP.
........
r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines
Add a few refcount data entries.
........
r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines
Add test suite for cmd module.
Written by Michael Schneider for GHOP.
........
r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines
Add examples to the ElementTree documentation.
Written by h4wk.cz for GHOP.
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r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines
Add "Using Python on Windows" document, by Robert Lehmann.
Written for GHOP.
........
r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines
Add example to mmap docs.
Written for GHOP by Rafal Rawicki.
........
r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines
Convert bdb.rst line endings to Unix style.
........
r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines
Add more entries to the glossary.
Written by Jeff Wheeler for GHOP.
........
2007-12-02 11:22:16 -04:00
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the error check! Also note that strictly speaking this code is not complete:
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2010-10-06 07:11:56 -03:00
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:c:func:`Py_BuildValue` may run out of memory, and this should be checked.
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2007-08-15 11:28:22 -03:00
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2009-01-03 17:18:54 -04:00
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You may also call a function with keyword arguments by using
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2010-10-06 07:11:56 -03:00
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:c:func:`PyObject_Call`, which supports arguments and keyword arguments. As in
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the above example, we use :c:func:`Py_BuildValue` to construct the dictionary. ::
|
Merged revisions 59259-59274 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines
Issue #1531: Read fileobj from the current offset, do not seek to
the start.
(will backport to 2.5)
........
r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines
Document PyEval_* functions from ceval.c.
Credits to Michael Sloan from GHOP.
........
r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines
Add a few refcount data entries.
........
r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines
Add test suite for cmd module.
Written by Michael Schneider for GHOP.
........
r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines
Add examples to the ElementTree documentation.
Written by h4wk.cz for GHOP.
........
r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines
Add "Using Python on Windows" document, by Robert Lehmann.
Written for GHOP.
........
r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines
Add example to mmap docs.
Written for GHOP by Rafal Rawicki.
........
r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines
Convert bdb.rst line endings to Unix style.
........
r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines
Add more entries to the glossary.
Written by Jeff Wheeler for GHOP.
........
2007-12-02 11:22:16 -04:00
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PyObject *dict;
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...
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dict = Py_BuildValue("{s:i}", "name", val);
|
Merged revisions 70712,70714,70764-70765,70769-70771,70773,70776-70777,70788-70789,70824,70828,70832,70836,70842,70851,70855,70857,70866-70872,70883,70885,70893-70894,70896-70897,70903,70905-70907,70915,70927,70933,70951,70960,70962-70964,70998,71001,71006,71008,71010-71011,71019,71037,71056,71094,71101-71103,71106,71119,71123,71149-71150,71203,71212,71214-71217,71221,71240 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r70712 | benjamin.peterson | 2009-03-30 10:15:38 -0500 (Mon, 30 Mar 2009) | 1 line
don't rely on the order dict repr #5605
........
r70714 | brett.cannon | 2009-03-30 10:20:53 -0500 (Mon, 30 Mar 2009) | 1 line
Add an entry to developers.txt.
........
r70764 | martin.v.loewis | 2009-03-30 17:06:33 -0500 (Mon, 30 Mar 2009) | 2 lines
Add several VM developers.
........
r70765 | georg.brandl | 2009-03-30 17:09:34 -0500 (Mon, 30 Mar 2009) | 1 line
#5199: make warning about vars() assignment more visible.
........
r70769 | andrew.kuchling | 2009-03-30 17:29:53 -0500 (Mon, 30 Mar 2009) | 1 line
Remove comment
........
r70770 | andrew.kuchling | 2009-03-30 17:30:20 -0500 (Mon, 30 Mar 2009) | 1 line
Add several items and placeholders
........
r70771 | andrew.kuchling | 2009-03-30 17:31:11 -0500 (Mon, 30 Mar 2009) | 1 line
Many edits
........
r70773 | georg.brandl | 2009-03-30 17:43:00 -0500 (Mon, 30 Mar 2009) | 1 line
#5039: make it clear that the impl. note refers to CPython.
........
r70776 | andrew.kuchling | 2009-03-30 18:08:24 -0500 (Mon, 30 Mar 2009) | 1 line
typo fix
........
r70777 | andrew.kuchling | 2009-03-30 18:09:46 -0500 (Mon, 30 Mar 2009) | 1 line
Add more items
........
r70788 | andrew.kuchling | 2009-03-30 20:21:01 -0500 (Mon, 30 Mar 2009) | 1 line
Add various items
........
r70789 | georg.brandl | 2009-03-30 20:25:15 -0500 (Mon, 30 Mar 2009) | 1 line
Fix a wrong struct field assignment (docstring as closure).
........
r70824 | georg.brandl | 2009-03-31 10:43:20 -0500 (Tue, 31 Mar 2009) | 1 line
#5519: remove reference to Kodos, which seems dead.
........
r70828 | georg.brandl | 2009-03-31 10:50:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5581: fget argument of abstractproperty is optional as well.
........
r70832 | georg.brandl | 2009-03-31 11:31:11 -0500 (Tue, 31 Mar 2009) | 1 line
#1386675: specify WindowsError as the exception, because it has a winerror attribute that EnvironmentError doesnt have.
........
r70836 | georg.brandl | 2009-03-31 11:50:25 -0500 (Tue, 31 Mar 2009) | 1 line
#5417: replace references to undocumented functions by ones to documented functions.
........
r70842 | georg.brandl | 2009-03-31 12:13:06 -0500 (Tue, 31 Mar 2009) | 1 line
#970783: document PyObject_Generic[GS]etAttr.
........
r70851 | georg.brandl | 2009-03-31 13:26:55 -0500 (Tue, 31 Mar 2009) | 1 line
#837577: note cryptic return value of spawn*e on invalid env dicts.
........
r70855 | georg.brandl | 2009-03-31 13:30:37 -0500 (Tue, 31 Mar 2009) | 1 line
#5245: note that PyRun_SimpleString doesnt return on SystemExit.
........
r70857 | georg.brandl | 2009-03-31 13:33:10 -0500 (Tue, 31 Mar 2009) | 1 line
#5227: note that Py_Main doesnt return on SystemExit.
........
r70866 | georg.brandl | 2009-03-31 14:06:57 -0500 (Tue, 31 Mar 2009) | 1 line
#4882: document named group behavior a bit better.
........
r70867 | georg.brandl | 2009-03-31 14:10:35 -0500 (Tue, 31 Mar 2009) | 1 line
#1096310: document usage of sys.__std*__ a bit better.
........
r70868 | georg.brandl | 2009-03-31 14:12:17 -0500 (Tue, 31 Mar 2009) | 1 line
#5190: export make_option in __all__.
........
r70869 | georg.brandl | 2009-03-31 14:14:42 -0500 (Tue, 31 Mar 2009) | 1 line
Fix-up unwanted change.
........
r70870 | georg.brandl | 2009-03-31 14:26:24 -0500 (Tue, 31 Mar 2009) | 1 line
#4411: document mro() and __mro__. (I hope I got it right.)
........
r70871 | georg.brandl | 2009-03-31 14:30:56 -0500 (Tue, 31 Mar 2009) | 1 line
#5618: fix typo.
........
r70872 | r.david.murray | 2009-03-31 14:31:17 -0500 (Tue, 31 Mar 2009) | 3 lines
Delete out-of-date and little-known README from the test
directory by consensus of devs at pycon sprint.
........
r70883 | georg.brandl | 2009-03-31 15:41:08 -0500 (Tue, 31 Mar 2009) | 1 line
#1674032: return value of flag from Event.wait(). OKed by Guido.
........
r70885 | tarek.ziade | 2009-03-31 15:48:31 -0500 (Tue, 31 Mar 2009) | 1 line
using log.warn for sys.stderr
........
r70893 | georg.brandl | 2009-03-31 15:56:32 -0500 (Tue, 31 Mar 2009) | 1 line
#1530012: move TQS section before raw strings.
........
r70894 | benjamin.peterson | 2009-03-31 16:06:30 -0500 (Tue, 31 Mar 2009) | 1 line
take the usual lock precautions around _active_limbo_lock
........
r70896 | georg.brandl | 2009-03-31 16:15:33 -0500 (Tue, 31 Mar 2009) | 1 line
#5598: document DocFileSuite *args argument.
........
r70897 | benjamin.peterson | 2009-03-31 16:34:42 -0500 (Tue, 31 Mar 2009) | 1 line
fix Thread.ident when it is the main thread or a dummy thread #5632
........
r70903 | georg.brandl | 2009-03-31 16:45:18 -0500 (Tue, 31 Mar 2009) | 1 line
#1676135: remove trailing slashes from --prefix argument.
........
r70905 | georg.brandl | 2009-03-31 17:03:40 -0500 (Tue, 31 Mar 2009) | 1 line
#5563: more documentation for bdist_msi.
........
r70906 | georg.brandl | 2009-03-31 17:11:53 -0500 (Tue, 31 Mar 2009) | 1 line
#1651995: fix _convert_ref for non-ASCII characters.
........
r70907 | georg.brandl | 2009-03-31 17:18:19 -0500 (Tue, 31 Mar 2009) | 1 line
#3427: document correct return type for urlopen().info().
........
r70915 | georg.brandl | 2009-03-31 17:40:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5018: remove confusing paragraph.
........
r70927 | georg.brandl | 2009-03-31 18:01:27 -0500 (Tue, 31 Mar 2009) | 1 line
Dont shout to users.
........
r70933 | georg.brandl | 2009-03-31 19:04:33 -0500 (Tue, 31 Mar 2009) | 2 lines
Issue #5635: Fix running test_sys with tracing enabled.
........
r70951 | georg.brandl | 2009-04-01 09:02:27 -0500 (Wed, 01 Apr 2009) | 1 line
Add Maksim, who worked on several issues at the sprint.
........
r70960 | jesse.noller | 2009-04-01 11:42:19 -0500 (Wed, 01 Apr 2009) | 1 line
Issue 3270: document Listener address restrictions on windows
........
r70962 | brett.cannon | 2009-04-01 12:07:16 -0500 (Wed, 01 Apr 2009) | 2 lines
Ron DuPlain was given commit privileges at PyCon 2009 to work on 3to2.
........
r70963 | georg.brandl | 2009-04-01 12:46:01 -0500 (Wed, 01 Apr 2009) | 1 line
#5655: fix docstring oversight.
........
r70964 | brett.cannon | 2009-04-01 12:52:13 -0500 (Wed, 01 Apr 2009) | 2 lines
Paul Kippes was given commit privileges to work on 3to2.
........
r70998 | georg.brandl | 2009-04-01 16:54:21 -0500 (Wed, 01 Apr 2009) | 1 line
In Pdb, stop assigning values to __builtin__._ which interferes with the one commonly installed by gettext.
........
r71001 | brett.cannon | 2009-04-01 18:01:12 -0500 (Wed, 01 Apr 2009) | 3 lines
Add my initials to Misc/developers.txt. Names are now sorted by number of
characters in the person's name.
........
r71006 | georg.brandl | 2009-04-01 18:32:17 -0500 (Wed, 01 Apr 2009) | 1 line
Cache the f_locals dict of the current frame, since every access to frame.f_locals overrides its contents with the real locals which undoes modifications made by the debugging user.
........
r71008 | andrew.kuchling | 2009-04-01 19:02:14 -0500 (Wed, 01 Apr 2009) | 1 line
Typo fix
........
r71010 | benjamin.peterson | 2009-04-01 19:11:52 -0500 (Wed, 01 Apr 2009) | 1 line
fix markup
........
r71011 | benjamin.peterson | 2009-04-01 19:12:47 -0500 (Wed, 01 Apr 2009) | 1 line
this should be :noindex:
........
r71019 | georg.brandl | 2009-04-01 21:00:01 -0500 (Wed, 01 Apr 2009) | 1 line
Fix test_doctest, missed two assignments to curframe.
........
r71037 | r.david.murray | 2009-04-01 23:34:04 -0500 (Wed, 01 Apr 2009) | 6 lines
Clarify that datetime strftime does not produce leap seconds and datetime
strptime does not accept it in the strftime behavior section of the
datetime docs.
Closes issue 2568.
........
r71056 | georg.brandl | 2009-04-02 12:43:07 -0500 (Thu, 02 Apr 2009) | 2 lines
Actually the displayhook should print the repr.
........
r71094 | vinay.sajip | 2009-04-03 05:23:18 -0500 (Fri, 03 Apr 2009) | 1 line
Added warning about logging use from asynchronous signal handlers.
........
r71101 | andrew.kuchling | 2009-04-03 16:43:00 -0500 (Fri, 03 Apr 2009) | 1 line
Add some items
........
r71102 | andrew.kuchling | 2009-04-03 16:44:49 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the'; grammar fix
........
r71103 | andrew.kuchling | 2009-04-03 16:45:29 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the' duplication
........
r71106 | vinay.sajip | 2009-04-03 16:58:16 -0500 (Fri, 03 Apr 2009) | 1 line
Clarified warning about logging use from asynchronous signal handlers.
........
r71119 | raymond.hettinger | 2009-04-04 00:37:47 -0500 (Sat, 04 Apr 2009) | 1 line
Add helpful link.
........
r71123 | r.david.murray | 2009-04-04 01:39:56 -0500 (Sat, 04 Apr 2009) | 2 lines
Fix error in description of 'oct' (issue 5678).
........
r71149 | georg.brandl | 2009-04-04 08:42:39 -0500 (Sat, 04 Apr 2009) | 1 line
#5642: clarify map() compatibility to the builtin.
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r71150 | georg.brandl | 2009-04-04 08:45:49 -0500 (Sat, 04 Apr 2009) | 1 line
#5601: clarify that webbrowser is not meant for file names.
........
r71203 | benjamin.peterson | 2009-04-04 18:46:34 -0500 (Sat, 04 Apr 2009) | 1 line
note how using iter* are unsafe while mutating and document iter(dict)
........
r71212 | georg.brandl | 2009-04-05 05:24:20 -0500 (Sun, 05 Apr 2009) | 1 line
#1742837: expand HTTP server docs, and fix SocketServer ones to document methods as methods, not functions.
........
r71214 | georg.brandl | 2009-04-05 05:29:57 -0500 (Sun, 05 Apr 2009) | 1 line
Normalize spelling of Mac OS X.
........
r71215 | georg.brandl | 2009-04-05 05:32:26 -0500 (Sun, 05 Apr 2009) | 1 line
Avoid sure signs of a diseased mind.
........
r71216 | georg.brandl | 2009-04-05 05:41:02 -0500 (Sun, 05 Apr 2009) | 1 line
#1718017: document the relation of os.path and the posixpath, ntpath etc. modules better.
........
r71217 | georg.brandl | 2009-04-05 05:48:47 -0500 (Sun, 05 Apr 2009) | 1 line
#1726172: dont raise an unexpected IndexError if a voidresp() call has an empty response.
........
r71221 | vinay.sajip | 2009-04-05 06:06:24 -0500 (Sun, 05 Apr 2009) | 1 line
Issue #5695: Moved logging.captureWarnings() call inside with statement in WarningsTest.test_warnings.
........
r71240 | georg.brandl | 2009-04-05 09:40:06 -0500 (Sun, 05 Apr 2009) | 1 line
#5370: doc update about unpickling objects with custom __getattr__ etc. methods.
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2009-04-05 16:13:16 -03:00
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|
|
result = PyObject_Call(my_callback, NULL, dict);
|
Merged revisions 59259-59274 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59260 | lars.gustaebel | 2007-12-01 22:02:12 +0100 (Sat, 01 Dec 2007) | 5 lines
Issue #1531: Read fileobj from the current offset, do not seek to
the start.
(will backport to 2.5)
........
r59262 | georg.brandl | 2007-12-01 23:24:47 +0100 (Sat, 01 Dec 2007) | 4 lines
Document PyEval_* functions from ceval.c.
Credits to Michael Sloan from GHOP.
........
r59263 | georg.brandl | 2007-12-01 23:27:56 +0100 (Sat, 01 Dec 2007) | 2 lines
Add a few refcount data entries.
........
r59264 | georg.brandl | 2007-12-01 23:38:48 +0100 (Sat, 01 Dec 2007) | 4 lines
Add test suite for cmd module.
Written by Michael Schneider for GHOP.
........
r59265 | georg.brandl | 2007-12-01 23:42:46 +0100 (Sat, 01 Dec 2007) | 3 lines
Add examples to the ElementTree documentation.
Written by h4wk.cz for GHOP.
........
r59266 | georg.brandl | 2007-12-02 00:12:45 +0100 (Sun, 02 Dec 2007) | 3 lines
Add "Using Python on Windows" document, by Robert Lehmann.
Written for GHOP.
........
r59271 | georg.brandl | 2007-12-02 15:34:34 +0100 (Sun, 02 Dec 2007) | 3 lines
Add example to mmap docs.
Written for GHOP by Rafal Rawicki.
........
r59272 | georg.brandl | 2007-12-02 15:37:29 +0100 (Sun, 02 Dec 2007) | 2 lines
Convert bdb.rst line endings to Unix style.
........
r59274 | georg.brandl | 2007-12-02 15:58:50 +0100 (Sun, 02 Dec 2007) | 4 lines
Add more entries to the glossary.
Written by Jeff Wheeler for GHOP.
........
2007-12-02 11:22:16 -04:00
|
|
|
Py_DECREF(dict);
|
|
|
|
if (result == NULL)
|
|
|
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return NULL; /* Pass error back */
|
|
|
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/* Here maybe use the result */
|
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Py_DECREF(result);
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2007-08-15 11:28:22 -03:00
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|
|
Merged revisions 70712,70714,70764-70765,70769-70771,70773,70776-70777,70788-70789,70824,70828,70832,70836,70842,70851,70855,70857,70866-70872,70883,70885,70893-70894,70896-70897,70903,70905-70907,70915,70927,70933,70951,70960,70962-70964,70998,71001,71006,71008,71010-71011,71019,71037,71056,71094,71101-71103,71106,71119,71123,71149-71150,71203,71212,71214-71217,71221,71240 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r70712 | benjamin.peterson | 2009-03-30 10:15:38 -0500 (Mon, 30 Mar 2009) | 1 line
don't rely on the order dict repr #5605
........
r70714 | brett.cannon | 2009-03-30 10:20:53 -0500 (Mon, 30 Mar 2009) | 1 line
Add an entry to developers.txt.
........
r70764 | martin.v.loewis | 2009-03-30 17:06:33 -0500 (Mon, 30 Mar 2009) | 2 lines
Add several VM developers.
........
r70765 | georg.brandl | 2009-03-30 17:09:34 -0500 (Mon, 30 Mar 2009) | 1 line
#5199: make warning about vars() assignment more visible.
........
r70769 | andrew.kuchling | 2009-03-30 17:29:53 -0500 (Mon, 30 Mar 2009) | 1 line
Remove comment
........
r70770 | andrew.kuchling | 2009-03-30 17:30:20 -0500 (Mon, 30 Mar 2009) | 1 line
Add several items and placeholders
........
r70771 | andrew.kuchling | 2009-03-30 17:31:11 -0500 (Mon, 30 Mar 2009) | 1 line
Many edits
........
r70773 | georg.brandl | 2009-03-30 17:43:00 -0500 (Mon, 30 Mar 2009) | 1 line
#5039: make it clear that the impl. note refers to CPython.
........
r70776 | andrew.kuchling | 2009-03-30 18:08:24 -0500 (Mon, 30 Mar 2009) | 1 line
typo fix
........
r70777 | andrew.kuchling | 2009-03-30 18:09:46 -0500 (Mon, 30 Mar 2009) | 1 line
Add more items
........
r70788 | andrew.kuchling | 2009-03-30 20:21:01 -0500 (Mon, 30 Mar 2009) | 1 line
Add various items
........
r70789 | georg.brandl | 2009-03-30 20:25:15 -0500 (Mon, 30 Mar 2009) | 1 line
Fix a wrong struct field assignment (docstring as closure).
........
r70824 | georg.brandl | 2009-03-31 10:43:20 -0500 (Tue, 31 Mar 2009) | 1 line
#5519: remove reference to Kodos, which seems dead.
........
r70828 | georg.brandl | 2009-03-31 10:50:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5581: fget argument of abstractproperty is optional as well.
........
r70832 | georg.brandl | 2009-03-31 11:31:11 -0500 (Tue, 31 Mar 2009) | 1 line
#1386675: specify WindowsError as the exception, because it has a winerror attribute that EnvironmentError doesnt have.
........
r70836 | georg.brandl | 2009-03-31 11:50:25 -0500 (Tue, 31 Mar 2009) | 1 line
#5417: replace references to undocumented functions by ones to documented functions.
........
r70842 | georg.brandl | 2009-03-31 12:13:06 -0500 (Tue, 31 Mar 2009) | 1 line
#970783: document PyObject_Generic[GS]etAttr.
........
r70851 | georg.brandl | 2009-03-31 13:26:55 -0500 (Tue, 31 Mar 2009) | 1 line
#837577: note cryptic return value of spawn*e on invalid env dicts.
........
r70855 | georg.brandl | 2009-03-31 13:30:37 -0500 (Tue, 31 Mar 2009) | 1 line
#5245: note that PyRun_SimpleString doesnt return on SystemExit.
........
r70857 | georg.brandl | 2009-03-31 13:33:10 -0500 (Tue, 31 Mar 2009) | 1 line
#5227: note that Py_Main doesnt return on SystemExit.
........
r70866 | georg.brandl | 2009-03-31 14:06:57 -0500 (Tue, 31 Mar 2009) | 1 line
#4882: document named group behavior a bit better.
........
r70867 | georg.brandl | 2009-03-31 14:10:35 -0500 (Tue, 31 Mar 2009) | 1 line
#1096310: document usage of sys.__std*__ a bit better.
........
r70868 | georg.brandl | 2009-03-31 14:12:17 -0500 (Tue, 31 Mar 2009) | 1 line
#5190: export make_option in __all__.
........
r70869 | georg.brandl | 2009-03-31 14:14:42 -0500 (Tue, 31 Mar 2009) | 1 line
Fix-up unwanted change.
........
r70870 | georg.brandl | 2009-03-31 14:26:24 -0500 (Tue, 31 Mar 2009) | 1 line
#4411: document mro() and __mro__. (I hope I got it right.)
........
r70871 | georg.brandl | 2009-03-31 14:30:56 -0500 (Tue, 31 Mar 2009) | 1 line
#5618: fix typo.
........
r70872 | r.david.murray | 2009-03-31 14:31:17 -0500 (Tue, 31 Mar 2009) | 3 lines
Delete out-of-date and little-known README from the test
directory by consensus of devs at pycon sprint.
........
r70883 | georg.brandl | 2009-03-31 15:41:08 -0500 (Tue, 31 Mar 2009) | 1 line
#1674032: return value of flag from Event.wait(). OKed by Guido.
........
r70885 | tarek.ziade | 2009-03-31 15:48:31 -0500 (Tue, 31 Mar 2009) | 1 line
using log.warn for sys.stderr
........
r70893 | georg.brandl | 2009-03-31 15:56:32 -0500 (Tue, 31 Mar 2009) | 1 line
#1530012: move TQS section before raw strings.
........
r70894 | benjamin.peterson | 2009-03-31 16:06:30 -0500 (Tue, 31 Mar 2009) | 1 line
take the usual lock precautions around _active_limbo_lock
........
r70896 | georg.brandl | 2009-03-31 16:15:33 -0500 (Tue, 31 Mar 2009) | 1 line
#5598: document DocFileSuite *args argument.
........
r70897 | benjamin.peterson | 2009-03-31 16:34:42 -0500 (Tue, 31 Mar 2009) | 1 line
fix Thread.ident when it is the main thread or a dummy thread #5632
........
r70903 | georg.brandl | 2009-03-31 16:45:18 -0500 (Tue, 31 Mar 2009) | 1 line
#1676135: remove trailing slashes from --prefix argument.
........
r70905 | georg.brandl | 2009-03-31 17:03:40 -0500 (Tue, 31 Mar 2009) | 1 line
#5563: more documentation for bdist_msi.
........
r70906 | georg.brandl | 2009-03-31 17:11:53 -0500 (Tue, 31 Mar 2009) | 1 line
#1651995: fix _convert_ref for non-ASCII characters.
........
r70907 | georg.brandl | 2009-03-31 17:18:19 -0500 (Tue, 31 Mar 2009) | 1 line
#3427: document correct return type for urlopen().info().
........
r70915 | georg.brandl | 2009-03-31 17:40:16 -0500 (Tue, 31 Mar 2009) | 1 line
#5018: remove confusing paragraph.
........
r70927 | georg.brandl | 2009-03-31 18:01:27 -0500 (Tue, 31 Mar 2009) | 1 line
Dont shout to users.
........
r70933 | georg.brandl | 2009-03-31 19:04:33 -0500 (Tue, 31 Mar 2009) | 2 lines
Issue #5635: Fix running test_sys with tracing enabled.
........
r70951 | georg.brandl | 2009-04-01 09:02:27 -0500 (Wed, 01 Apr 2009) | 1 line
Add Maksim, who worked on several issues at the sprint.
........
r70960 | jesse.noller | 2009-04-01 11:42:19 -0500 (Wed, 01 Apr 2009) | 1 line
Issue 3270: document Listener address restrictions on windows
........
r70962 | brett.cannon | 2009-04-01 12:07:16 -0500 (Wed, 01 Apr 2009) | 2 lines
Ron DuPlain was given commit privileges at PyCon 2009 to work on 3to2.
........
r70963 | georg.brandl | 2009-04-01 12:46:01 -0500 (Wed, 01 Apr 2009) | 1 line
#5655: fix docstring oversight.
........
r70964 | brett.cannon | 2009-04-01 12:52:13 -0500 (Wed, 01 Apr 2009) | 2 lines
Paul Kippes was given commit privileges to work on 3to2.
........
r70998 | georg.brandl | 2009-04-01 16:54:21 -0500 (Wed, 01 Apr 2009) | 1 line
In Pdb, stop assigning values to __builtin__._ which interferes with the one commonly installed by gettext.
........
r71001 | brett.cannon | 2009-04-01 18:01:12 -0500 (Wed, 01 Apr 2009) | 3 lines
Add my initials to Misc/developers.txt. Names are now sorted by number of
characters in the person's name.
........
r71006 | georg.brandl | 2009-04-01 18:32:17 -0500 (Wed, 01 Apr 2009) | 1 line
Cache the f_locals dict of the current frame, since every access to frame.f_locals overrides its contents with the real locals which undoes modifications made by the debugging user.
........
r71008 | andrew.kuchling | 2009-04-01 19:02:14 -0500 (Wed, 01 Apr 2009) | 1 line
Typo fix
........
r71010 | benjamin.peterson | 2009-04-01 19:11:52 -0500 (Wed, 01 Apr 2009) | 1 line
fix markup
........
r71011 | benjamin.peterson | 2009-04-01 19:12:47 -0500 (Wed, 01 Apr 2009) | 1 line
this should be :noindex:
........
r71019 | georg.brandl | 2009-04-01 21:00:01 -0500 (Wed, 01 Apr 2009) | 1 line
Fix test_doctest, missed two assignments to curframe.
........
r71037 | r.david.murray | 2009-04-01 23:34:04 -0500 (Wed, 01 Apr 2009) | 6 lines
Clarify that datetime strftime does not produce leap seconds and datetime
strptime does not accept it in the strftime behavior section of the
datetime docs.
Closes issue 2568.
........
r71056 | georg.brandl | 2009-04-02 12:43:07 -0500 (Thu, 02 Apr 2009) | 2 lines
Actually the displayhook should print the repr.
........
r71094 | vinay.sajip | 2009-04-03 05:23:18 -0500 (Fri, 03 Apr 2009) | 1 line
Added warning about logging use from asynchronous signal handlers.
........
r71101 | andrew.kuchling | 2009-04-03 16:43:00 -0500 (Fri, 03 Apr 2009) | 1 line
Add some items
........
r71102 | andrew.kuchling | 2009-04-03 16:44:49 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the'; grammar fix
........
r71103 | andrew.kuchling | 2009-04-03 16:45:29 -0500 (Fri, 03 Apr 2009) | 1 line
Fix 'the the' duplication
........
r71106 | vinay.sajip | 2009-04-03 16:58:16 -0500 (Fri, 03 Apr 2009) | 1 line
Clarified warning about logging use from asynchronous signal handlers.
........
r71119 | raymond.hettinger | 2009-04-04 00:37:47 -0500 (Sat, 04 Apr 2009) | 1 line
Add helpful link.
........
r71123 | r.david.murray | 2009-04-04 01:39:56 -0500 (Sat, 04 Apr 2009) | 2 lines
Fix error in description of 'oct' (issue 5678).
........
r71149 | georg.brandl | 2009-04-04 08:42:39 -0500 (Sat, 04 Apr 2009) | 1 line
#5642: clarify map() compatibility to the builtin.
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r71150 | georg.brandl | 2009-04-04 08:45:49 -0500 (Sat, 04 Apr 2009) | 1 line
#5601: clarify that webbrowser is not meant for file names.
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r71203 | benjamin.peterson | 2009-04-04 18:46:34 -0500 (Sat, 04 Apr 2009) | 1 line
note how using iter* are unsafe while mutating and document iter(dict)
........
r71212 | georg.brandl | 2009-04-05 05:24:20 -0500 (Sun, 05 Apr 2009) | 1 line
#1742837: expand HTTP server docs, and fix SocketServer ones to document methods as methods, not functions.
........
r71214 | georg.brandl | 2009-04-05 05:29:57 -0500 (Sun, 05 Apr 2009) | 1 line
Normalize spelling of Mac OS X.
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r71215 | georg.brandl | 2009-04-05 05:32:26 -0500 (Sun, 05 Apr 2009) | 1 line
Avoid sure signs of a diseased mind.
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r71216 | georg.brandl | 2009-04-05 05:41:02 -0500 (Sun, 05 Apr 2009) | 1 line
#1718017: document the relation of os.path and the posixpath, ntpath etc. modules better.
........
r71217 | georg.brandl | 2009-04-05 05:48:47 -0500 (Sun, 05 Apr 2009) | 1 line
#1726172: dont raise an unexpected IndexError if a voidresp() call has an empty response.
........
r71221 | vinay.sajip | 2009-04-05 06:06:24 -0500 (Sun, 05 Apr 2009) | 1 line
Issue #5695: Moved logging.captureWarnings() call inside with statement in WarningsTest.test_warnings.
........
r71240 | georg.brandl | 2009-04-05 09:40:06 -0500 (Sun, 05 Apr 2009) | 1 line
#5370: doc update about unpickling objects with custom __getattr__ etc. methods.
........
2009-04-05 16:13:16 -03:00
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2007-08-15 11:28:22 -03:00
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.. _parsetuple:
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Extracting Parameters in Extension Functions
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============================================
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.. index:: single: PyArg_ParseTuple()
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2010-10-06 07:11:56 -03:00
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The :c:func:`PyArg_ParseTuple` function is declared as follows::
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2007-08-15 11:28:22 -03:00
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2015-06-21 11:11:21 -03:00
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int PyArg_ParseTuple(PyObject *arg, const char *format, ...);
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2007-08-15 11:28:22 -03:00
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The *arg* argument must be a tuple object containing an argument list passed
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from Python to a C function. The *format* argument must be a format string,
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whose syntax is explained in :ref:`arg-parsing` in the Python/C API Reference
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Manual. The remaining arguments must be addresses of variables whose type is
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determined by the format string.
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2010-10-06 07:11:56 -03:00
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Note that while :c:func:`PyArg_ParseTuple` checks that the Python arguments have
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2007-08-15 11:28:22 -03:00
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the required types, it cannot check the validity of the addresses of C variables
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passed to the call: if you make mistakes there, your code will probably crash or
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at least overwrite random bits in memory. So be careful!
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Note that any Python object references which are provided to the caller are
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*borrowed* references; do not decrement their reference count!
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Some example calls::
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2008-11-23 19:49:16 -04:00
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#define PY_SSIZE_T_CLEAN /* Make "s#" use Py_ssize_t rather than int. */
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#include <Python.h>
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::
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2007-08-15 11:28:22 -03:00
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int ok;
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int i, j;
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long k, l;
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const char *s;
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2008-11-23 19:49:16 -04:00
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Py_ssize_t size;
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2007-08-15 11:28:22 -03:00
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ok = PyArg_ParseTuple(args, ""); /* No arguments */
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/* Python call: f() */
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::
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ok = PyArg_ParseTuple(args, "s", &s); /* A string */
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/* Possible Python call: f('whoops!') */
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::
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ok = PyArg_ParseTuple(args, "lls", &k, &l, &s); /* Two longs and a string */
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/* Possible Python call: f(1, 2, 'three') */
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::
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ok = PyArg_ParseTuple(args, "(ii)s#", &i, &j, &s, &size);
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/* A pair of ints and a string, whose size is also returned */
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/* Possible Python call: f((1, 2), 'three') */
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::
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{
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const char *file;
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const char *mode = "r";
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int bufsize = 0;
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ok = PyArg_ParseTuple(args, "s|si", &file, &mode, &bufsize);
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/* A string, and optionally another string and an integer */
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/* Possible Python calls:
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f('spam')
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f('spam', 'w')
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f('spam', 'wb', 100000) */
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}
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::
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{
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int left, top, right, bottom, h, v;
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ok = PyArg_ParseTuple(args, "((ii)(ii))(ii)",
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&left, &top, &right, &bottom, &h, &v);
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/* A rectangle and a point */
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/* Possible Python call:
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f(((0, 0), (400, 300)), (10, 10)) */
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}
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::
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{
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Py_complex c;
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ok = PyArg_ParseTuple(args, "D:myfunction", &c);
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/* a complex, also providing a function name for errors */
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/* Possible Python call: myfunction(1+2j) */
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}
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.. _parsetupleandkeywords:
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Keyword Parameters for Extension Functions
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==========================================
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.. index:: single: PyArg_ParseTupleAndKeywords()
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2010-10-06 07:11:56 -03:00
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The :c:func:`PyArg_ParseTupleAndKeywords` function is declared as follows::
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int PyArg_ParseTupleAndKeywords(PyObject *arg, PyObject *kwdict,
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const char *format, char *kwlist[], ...);
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2007-08-15 11:28:22 -03:00
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The *arg* and *format* parameters are identical to those of the
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2010-10-06 07:11:56 -03:00
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:c:func:`PyArg_ParseTuple` function. The *kwdict* parameter is the dictionary of
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2007-08-15 11:28:22 -03:00
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keywords received as the third parameter from the Python runtime. The *kwlist*
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parameter is a *NULL*-terminated list of strings which identify the parameters;
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the names are matched with the type information from *format* from left to
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2010-10-06 07:11:56 -03:00
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right. On success, :c:func:`PyArg_ParseTupleAndKeywords` returns true, otherwise
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it returns false and raises an appropriate exception.
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.. note::
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Nested tuples cannot be parsed when using keyword arguments! Keyword parameters
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passed in which are not present in the *kwlist* will cause :exc:`TypeError` to
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be raised.
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.. index:: single: Philbrick, Geoff
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Here is an example module which uses keywords, based on an example by Geoff
|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
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r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
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r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
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r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
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r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
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r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
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r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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Philbrick (philbrick@hks.com)::
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2007-08-15 11:28:22 -03:00
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#include "Python.h"
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static PyObject *
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keywdarg_parrot(PyObject *self, PyObject *args, PyObject *keywds)
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2009-01-03 17:18:54 -04:00
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{
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2007-08-15 11:28:22 -03:00
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int voltage;
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char *state = "a stiff";
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char *action = "voom";
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char *type = "Norwegian Blue";
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static char *kwlist[] = {"voltage", "state", "action", "type", NULL};
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2009-01-03 17:18:54 -04:00
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if (!PyArg_ParseTupleAndKeywords(args, keywds, "i|sss", kwlist,
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2007-08-15 11:28:22 -03:00
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&voltage, &state, &action, &type))
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2009-01-03 17:18:54 -04:00
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return NULL;
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2007-08-15 11:28:22 -03:00
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2009-01-03 17:18:54 -04:00
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printf("-- This parrot wouldn't %s if you put %i Volts through it.\n",
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2007-08-15 11:28:22 -03:00
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action, voltage);
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printf("-- Lovely plumage, the %s -- It's %s!\n", type, state);
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2013-10-06 15:46:08 -03:00
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Py_RETURN_NONE;
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2007-08-15 11:28:22 -03:00
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}
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static PyMethodDef keywdarg_methods[] = {
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/* The cast of the function is necessary since PyCFunction values
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* only take two PyObject* parameters, and keywdarg_parrot() takes
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* three.
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*/
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{"parrot", (PyCFunction)keywdarg_parrot, METH_VARARGS | METH_KEYWORDS,
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"Print a lovely skit to standard output."},
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{NULL, NULL, 0, NULL} /* sentinel */
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};
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2012-08-15 08:49:49 -03:00
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static struct PyModuleDef keywdargmodule = {
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PyModuleDef_HEAD_INIT,
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"keywdarg",
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NULL,
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-1,
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keywdarg_methods
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};
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2007-08-15 11:28:22 -03:00
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2012-08-15 08:49:49 -03:00
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PyMODINIT_FUNC
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PyInit_keywdarg(void)
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2007-08-15 11:28:22 -03:00
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{
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2012-08-15 08:49:49 -03:00
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return PyModule_Create(&keywdargmodule);
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2007-08-15 11:28:22 -03:00
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}
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.. _buildvalue:
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Building Arbitrary Values
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=========================
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2010-10-06 07:11:56 -03:00
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This function is the counterpart to :c:func:`PyArg_ParseTuple`. It is declared
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2007-08-15 11:28:22 -03:00
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as follows::
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|
|
2015-06-21 11:11:21 -03:00
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PyObject *Py_BuildValue(const char *format, ...);
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2007-08-15 11:28:22 -03:00
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It recognizes a set of format units similar to the ones recognized by
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2010-10-06 07:11:56 -03:00
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:c:func:`PyArg_ParseTuple`, but the arguments (which are input to the function,
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2007-08-15 11:28:22 -03:00
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not output) must not be pointers, just values. It returns a new Python object,
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suitable for returning from a C function called from Python.
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|
2010-10-06 07:11:56 -03:00
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One difference with :c:func:`PyArg_ParseTuple`: while the latter requires its
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2007-08-15 11:28:22 -03:00
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first argument to be a tuple (since Python argument lists are always represented
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2010-10-06 07:11:56 -03:00
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as tuples internally), :c:func:`Py_BuildValue` does not always build a tuple. It
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2007-08-15 11:28:22 -03:00
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builds a tuple only if its format string contains two or more format units. If
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the format string is empty, it returns ``None``; if it contains exactly one
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format unit, it returns whatever object is described by that format unit. To
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force it to return a tuple of size 0 or one, parenthesize the format string.
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|
2016-07-26 06:18:21 -03:00
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Examples (to the left the call, to the right the resulting Python value):
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.. code-block:: none
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2007-08-15 11:28:22 -03:00
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Py_BuildValue("") None
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Py_BuildValue("i", 123) 123
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Py_BuildValue("iii", 123, 456, 789) (123, 456, 789)
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Py_BuildValue("s", "hello") 'hello'
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Py_BuildValue("y", "hello") b'hello'
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Py_BuildValue("ss", "hello", "world") ('hello', 'world')
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Py_BuildValue("s#", "hello", 4) 'hell'
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Py_BuildValue("y#", "hello", 4) b'hell'
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Py_BuildValue("()") ()
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Py_BuildValue("(i)", 123) (123,)
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Py_BuildValue("(ii)", 123, 456) (123, 456)
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Py_BuildValue("(i,i)", 123, 456) (123, 456)
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Py_BuildValue("[i,i]", 123, 456) [123, 456]
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Py_BuildValue("{s:i,s:i}",
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"abc", 123, "def", 456) {'abc': 123, 'def': 456}
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Py_BuildValue("((ii)(ii)) (ii)",
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1, 2, 3, 4, 5, 6) (((1, 2), (3, 4)), (5, 6))
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.. _refcounts:
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Reference Counts
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================
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In languages like C or C++, the programmer is responsible for dynamic allocation
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and deallocation of memory on the heap. In C, this is done using the functions
|
2010-10-06 07:11:56 -03:00
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:c:func:`malloc` and :c:func:`free`. In C++, the operators ``new`` and
|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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|
``delete`` are used with essentially the same meaning and we'll restrict
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2007-08-15 11:28:22 -03:00
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|
|
the following discussion to the C case.
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|
|
2010-10-06 07:11:56 -03:00
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|
|
Every block of memory allocated with :c:func:`malloc` should eventually be
|
|
|
|
returned to the pool of available memory by exactly one call to :c:func:`free`.
|
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|
|
It is important to call :c:func:`free` at the right time. If a block's address
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|
|
is forgotten but :c:func:`free` is not called for it, the memory it occupies
|
2007-08-15 11:28:22 -03:00
|
|
|
cannot be reused until the program terminates. This is called a :dfn:`memory
|
2010-10-06 07:11:56 -03:00
|
|
|
leak`. On the other hand, if a program calls :c:func:`free` for a block and then
|
2007-08-15 11:28:22 -03:00
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|
|
continues to use the block, it creates a conflict with re-use of the block
|
2010-10-06 07:11:56 -03:00
|
|
|
through another :c:func:`malloc` call. This is called :dfn:`using freed memory`.
|
2007-08-15 11:28:22 -03:00
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|
It has the same bad consequences as referencing uninitialized data --- core
|
|
|
|
dumps, wrong results, mysterious crashes.
|
|
|
|
|
|
|
|
Common causes of memory leaks are unusual paths through the code. For instance,
|
|
|
|
a function may allocate a block of memory, do some calculation, and then free
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|
|
the block again. Now a change in the requirements for the function may add a
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|
|
test to the calculation that detects an error condition and can return
|
|
|
|
prematurely from the function. It's easy to forget to free the allocated memory
|
|
|
|
block when taking this premature exit, especially when it is added later to the
|
|
|
|
code. Such leaks, once introduced, often go undetected for a long time: the
|
|
|
|
error exit is taken only in a small fraction of all calls, and most modern
|
|
|
|
machines have plenty of virtual memory, so the leak only becomes apparent in a
|
|
|
|
long-running process that uses the leaking function frequently. Therefore, it's
|
|
|
|
important to prevent leaks from happening by having a coding convention or
|
|
|
|
strategy that minimizes this kind of errors.
|
|
|
|
|
2010-10-06 07:11:56 -03:00
|
|
|
Since Python makes heavy use of :c:func:`malloc` and :c:func:`free`, it needs a
|
2007-08-15 11:28:22 -03:00
|
|
|
strategy to avoid memory leaks as well as the use of freed memory. The chosen
|
|
|
|
method is called :dfn:`reference counting`. The principle is simple: every
|
|
|
|
object contains a counter, which is incremented when a reference to the object
|
|
|
|
is stored somewhere, and which is decremented when a reference to it is deleted.
|
|
|
|
When the counter reaches zero, the last reference to the object has been deleted
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and the object is freed.
|
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|
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|
|
|
|
An alternative strategy is called :dfn:`automatic garbage collection`.
|
|
|
|
(Sometimes, reference counting is also referred to as a garbage collection
|
|
|
|
strategy, hence my use of "automatic" to distinguish the two.) The big
|
|
|
|
advantage of automatic garbage collection is that the user doesn't need to call
|
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|
|
|
:c:func:`free` explicitly. (Another claimed advantage is an improvement in speed
|
2007-08-15 11:28:22 -03:00
|
|
|
or memory usage --- this is no hard fact however.) The disadvantage is that for
|
|
|
|
C, there is no truly portable automatic garbage collector, while reference
|
2010-10-06 07:11:56 -03:00
|
|
|
counting can be implemented portably (as long as the functions :c:func:`malloc`
|
|
|
|
and :c:func:`free` are available --- which the C Standard guarantees). Maybe some
|
2007-08-15 11:28:22 -03:00
|
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|
day a sufficiently portable automatic garbage collector will be available for C.
|
|
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|
Until then, we'll have to live with reference counts.
|
|
|
|
|
|
|
|
While Python uses the traditional reference counting implementation, it also
|
|
|
|
offers a cycle detector that works to detect reference cycles. This allows
|
|
|
|
applications to not worry about creating direct or indirect circular references;
|
|
|
|
these are the weakness of garbage collection implemented using only reference
|
|
|
|
counting. Reference cycles consist of objects which contain (possibly indirect)
|
|
|
|
references to themselves, so that each object in the cycle has a reference count
|
|
|
|
which is non-zero. Typical reference counting implementations are not able to
|
|
|
|
reclaim the memory belonging to any objects in a reference cycle, or referenced
|
|
|
|
from the objects in the cycle, even though there are no further references to
|
|
|
|
the cycle itself.
|
|
|
|
|
2014-10-31 06:38:49 -03:00
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|
The cycle detector is able to detect garbage cycles and can reclaim them.
|
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|
|
The :mod:`gc` module exposes a way to run the detector (the
|
2013-10-09 07:26:17 -03:00
|
|
|
:func:`~gc.collect` function), as well as configuration
|
2007-08-15 11:28:22 -03:00
|
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|
interfaces and the ability to disable the detector at runtime. The cycle
|
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|
|
detector is considered an optional component; though it is included by default,
|
2016-10-30 01:20:17 -03:00
|
|
|
it can be disabled at build time using the :option:`!--without-cycle-gc` option
|
2008-02-01 07:56:49 -04:00
|
|
|
to the :program:`configure` script on Unix platforms (including Mac OS X). If
|
|
|
|
the cycle detector is disabled in this way, the :mod:`gc` module will not be
|
|
|
|
available.
|
2007-08-15 11:28:22 -03:00
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|
|
|
|
|
|
|
|
|
.. _refcountsinpython:
|
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|
|
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|
|
Reference Counting in Python
|
|
|
|
----------------------------
|
|
|
|
|
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|
|
There are two macros, ``Py_INCREF(x)`` and ``Py_DECREF(x)``, which handle the
|
2010-10-06 07:11:56 -03:00
|
|
|
incrementing and decrementing of the reference count. :c:func:`Py_DECREF` also
|
2007-08-15 11:28:22 -03:00
|
|
|
frees the object when the count reaches zero. For flexibility, it doesn't call
|
2010-10-06 07:11:56 -03:00
|
|
|
:c:func:`free` directly --- rather, it makes a call through a function pointer in
|
2007-08-15 11:28:22 -03:00
|
|
|
the object's :dfn:`type object`. For this purpose (and others), every object
|
|
|
|
also contains a pointer to its type object.
|
|
|
|
|
|
|
|
The big question now remains: when to use ``Py_INCREF(x)`` and ``Py_DECREF(x)``?
|
|
|
|
Let's first introduce some terms. Nobody "owns" an object; however, you can
|
|
|
|
:dfn:`own a reference` to an object. An object's reference count is now defined
|
|
|
|
as the number of owned references to it. The owner of a reference is
|
2010-10-06 07:11:56 -03:00
|
|
|
responsible for calling :c:func:`Py_DECREF` when the reference is no longer
|
2007-08-15 11:28:22 -03:00
|
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|
needed. Ownership of a reference can be transferred. There are three ways to
|
2010-10-06 07:11:56 -03:00
|
|
|
dispose of an owned reference: pass it on, store it, or call :c:func:`Py_DECREF`.
|
2007-08-15 11:28:22 -03:00
|
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|
Forgetting to dispose of an owned reference creates a memory leak.
|
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|
It is also possible to :dfn:`borrow` [#]_ a reference to an object. The
|
2010-10-06 07:11:56 -03:00
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|
borrower of a reference should not call :c:func:`Py_DECREF`. The borrower must
|
2007-08-15 11:28:22 -03:00
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|
not hold on to the object longer than the owner from which it was borrowed.
|
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|
Using a borrowed reference after the owner has disposed of it risks using freed
|
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|
memory and should be avoided completely. [#]_
|
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|
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|
The advantage of borrowing over owning a reference is that you don't need to
|
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|
|
take care of disposing of the reference on all possible paths through the code
|
|
|
|
--- in other words, with a borrowed reference you don't run the risk of leaking
|
Merged revisions 67654,67676-67677,67681,67692,67725,67761,67784-67785,67787-67788,67802,67848-67850,67862-67864,67880,67882 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r67654 | georg.brandl | 2008-12-07 16:42:09 -0600 (Sun, 07 Dec 2008) | 2 lines
#4457: rewrite __import__() documentation.
........
r67676 | benjamin.peterson | 2008-12-08 20:03:03 -0600 (Mon, 08 Dec 2008) | 1 line
specify how things are copied
........
r67677 | benjamin.peterson | 2008-12-08 20:05:11 -0600 (Mon, 08 Dec 2008) | 1 line
revert unrelated change to installer script
........
r67681 | jeremy.hylton | 2008-12-09 15:03:10 -0600 (Tue, 09 Dec 2008) | 2 lines
Add simple unittests for Request
........
r67692 | amaury.forgeotdarc | 2008-12-10 18:03:42 -0600 (Wed, 10 Dec 2008) | 2 lines
#1030250: correctly pass the dry_run option to the mkpath() function.
........
r67725 | benjamin.peterson | 2008-12-12 22:02:20 -0600 (Fri, 12 Dec 2008) | 1 line
fix incorrect example
........
r67761 | benjamin.peterson | 2008-12-14 11:26:04 -0600 (Sun, 14 Dec 2008) | 1 line
fix missing bracket
........
r67784 | georg.brandl | 2008-12-15 02:33:58 -0600 (Mon, 15 Dec 2008) | 2 lines
#4446: document "platforms" argument for setup().
........
r67785 | georg.brandl | 2008-12-15 02:36:11 -0600 (Mon, 15 Dec 2008) | 2 lines
#4611: fix typo.
........
r67787 | georg.brandl | 2008-12-15 02:58:59 -0600 (Mon, 15 Dec 2008) | 2 lines
#4578: fix has_key() usage in compiler package.
........
r67788 | georg.brandl | 2008-12-15 03:07:39 -0600 (Mon, 15 Dec 2008) | 2 lines
#4568: remove limitation in varargs callback example.
........
r67802 | amaury.forgeotdarc | 2008-12-15 16:29:14 -0600 (Mon, 15 Dec 2008) | 4 lines
#3632: the "pyo" macro from gdbinit can now run when the GIL is released.
Patch by haypo.
........
r67848 | benjamin.peterson | 2008-12-18 20:28:56 -0600 (Thu, 18 Dec 2008) | 1 line
fix typo
........
r67849 | benjamin.peterson | 2008-12-18 20:31:35 -0600 (Thu, 18 Dec 2008) | 1 line
_call_method -> _callmethod and _get_value to _getvalue
........
r67850 | raymond.hettinger | 2008-12-19 03:06:07 -0600 (Fri, 19 Dec 2008) | 9 lines
Fix-up and clean-up docs for int.bit_length().
* Replace dramatic footnote with in-line comment about possible round-off errors in logarithms of large numbers.
* Add comments to the pure python code equivalent.
* replace floor() with int() in the mathematical equivalent so the type is correct (should be an int, not a float).
* add abs() to the mathematical equivalent so that it matches the previous line that it is supposed to be equivalent to.
* make one combined example with a negative input.
........
r67862 | benjamin.peterson | 2008-12-19 20:48:02 -0600 (Fri, 19 Dec 2008) | 1 line
copy sentence from docstring
........
r67863 | benjamin.peterson | 2008-12-19 20:51:26 -0600 (Fri, 19 Dec 2008) | 1 line
add headings
........
r67864 | benjamin.peterson | 2008-12-19 20:57:19 -0600 (Fri, 19 Dec 2008) | 1 line
beef up docstring
........
r67880 | benjamin.peterson | 2008-12-20 16:49:24 -0600 (Sat, 20 Dec 2008) | 1 line
remove redundant sentence
........
r67882 | benjamin.peterson | 2008-12-20 16:59:49 -0600 (Sat, 20 Dec 2008) | 1 line
add some recent releases to the list
........
2008-12-20 20:06:59 -04:00
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when a premature exit is taken. The disadvantage of borrowing over owning is
|
2007-08-15 11:28:22 -03:00
|
|
|
that there are some subtle situations where in seemingly correct code a borrowed
|
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|
reference can be used after the owner from which it was borrowed has in fact
|
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|
|
disposed of it.
|
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|
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|
A borrowed reference can be changed into an owned reference by calling
|
2010-10-06 07:11:56 -03:00
|
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|
:c:func:`Py_INCREF`. This does not affect the status of the owner from which the
|
2007-08-15 11:28:22 -03:00
|
|
|
reference was borrowed --- it creates a new owned reference, and gives full
|
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|
owner responsibilities (the new owner must dispose of the reference properly, as
|
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|
|
well as the previous owner).
|
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|
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.. _ownershiprules:
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|
Ownership Rules
|
|
|
|
---------------
|
|
|
|
|
|
|
|
Whenever an object reference is passed into or out of a function, it is part of
|
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|
the function's interface specification whether ownership is transferred with the
|
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|
reference or not.
|
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|
Most functions that return a reference to an object pass on ownership with the
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|
|
reference. In particular, all functions whose function it is to create a new
|
2010-10-06 07:11:56 -03:00
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object, such as :c:func:`PyLong_FromLong` and :c:func:`Py_BuildValue`, pass
|
2007-08-15 11:28:22 -03:00
|
|
|
ownership to the receiver. Even if the object is not actually new, you still
|
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|
|
receive ownership of a new reference to that object. For instance,
|
2010-10-06 07:11:56 -03:00
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|
:c:func:`PyLong_FromLong` maintains a cache of popular values and can return a
|
2007-08-15 11:28:22 -03:00
|
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|
reference to a cached item.
|
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|
Many functions that extract objects from other objects also transfer ownership
|
2010-10-06 07:11:56 -03:00
|
|
|
with the reference, for instance :c:func:`PyObject_GetAttrString`. The picture
|
2007-08-15 11:28:22 -03:00
|
|
|
is less clear, here, however, since a few common routines are exceptions:
|
2010-10-06 07:11:56 -03:00
|
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|
:c:func:`PyTuple_GetItem`, :c:func:`PyList_GetItem`, :c:func:`PyDict_GetItem`, and
|
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|
:c:func:`PyDict_GetItemString` all return references that you borrow from the
|
2007-08-15 11:28:22 -03:00
|
|
|
tuple, list or dictionary.
|
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|
2010-10-06 07:11:56 -03:00
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The function :c:func:`PyImport_AddModule` also returns a borrowed reference, even
|
2007-08-15 11:28:22 -03:00
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|
though it may actually create the object it returns: this is possible because an
|
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|
owned reference to the object is stored in ``sys.modules``.
|
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|
When you pass an object reference into another function, in general, the
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function borrows the reference from you --- if it needs to store it, it will use
|
2010-10-06 07:11:56 -03:00
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|
:c:func:`Py_INCREF` to become an independent owner. There are exactly two
|
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|
|
important exceptions to this rule: :c:func:`PyTuple_SetItem` and
|
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|
|
:c:func:`PyList_SetItem`. These functions take over ownership of the item passed
|
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|
to them --- even if they fail! (Note that :c:func:`PyDict_SetItem` and friends
|
2007-08-15 11:28:22 -03:00
|
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|
don't take over ownership --- they are "normal.")
|
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When a C function is called from Python, it borrows references to its arguments
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|
from the caller. The caller owns a reference to the object, so the borrowed
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|
reference's lifetime is guaranteed until the function returns. Only when such a
|
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|
|
borrowed reference must be stored or passed on, it must be turned into an owned
|
2010-10-06 07:11:56 -03:00
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reference by calling :c:func:`Py_INCREF`.
|
2007-08-15 11:28:22 -03:00
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The object reference returned from a C function that is called from Python must
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|
be an owned reference --- ownership is transferred from the function to its
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caller.
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.. _thinice:
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|
Thin Ice
|
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|
|
--------
|
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|
There are a few situations where seemingly harmless use of a borrowed reference
|
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|
|
can lead to problems. These all have to do with implicit invocations of the
|
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|
|
interpreter, which can cause the owner of a reference to dispose of it.
|
|
|
|
|
2010-10-06 07:11:56 -03:00
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|
The first and most important case to know about is using :c:func:`Py_DECREF` on
|
2007-08-15 11:28:22 -03:00
|
|
|
an unrelated object while borrowing a reference to a list item. For instance::
|
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|
|
|
|
|
|
void
|
|
|
|
bug(PyObject *list)
|
|
|
|
{
|
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|
|
PyObject *item = PyList_GetItem(list, 0);
|
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|
2007-12-02 19:08:39 -04:00
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PyList_SetItem(list, 1, PyLong_FromLong(0L));
|
2007-08-15 11:28:22 -03:00
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|
PyObject_Print(item, stdout, 0); /* BUG! */
|
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|
|
}
|
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|
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|
This function first borrows a reference to ``list[0]``, then replaces
|
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|
|
``list[1]`` with the value ``0``, and finally prints the borrowed reference.
|
|
|
|
Looks harmless, right? But it's not!
|
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|
|
|
2010-10-06 07:11:56 -03:00
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|
Let's follow the control flow into :c:func:`PyList_SetItem`. The list owns
|
2007-08-15 11:28:22 -03:00
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|
references to all its items, so when item 1 is replaced, it has to dispose of
|
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|
the original item 1. Now let's suppose the original item 1 was an instance of a
|
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|
|
user-defined class, and let's further suppose that the class defined a
|
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|
:meth:`__del__` method. If this class instance has a reference count of 1,
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|
disposing of it will call its :meth:`__del__` method.
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|
Since it is written in Python, the :meth:`__del__` method can execute arbitrary
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|
Python code. Could it perhaps do something to invalidate the reference to
|
2010-10-06 07:11:56 -03:00
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|
|
``item`` in :c:func:`bug`? You bet! Assuming that the list passed into
|
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|
:c:func:`bug` is accessible to the :meth:`__del__` method, it could execute a
|
2007-08-15 11:28:22 -03:00
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|
|
statement to the effect of ``del list[0]``, and assuming this was the last
|
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|
|
reference to that object, it would free the memory associated with it, thereby
|
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|
invalidating ``item``.
|
|
|
|
|
|
|
|
The solution, once you know the source of the problem, is easy: temporarily
|
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|
|
increment the reference count. The correct version of the function reads::
|
|
|
|
|
|
|
|
void
|
|
|
|
no_bug(PyObject *list)
|
|
|
|
{
|
|
|
|
PyObject *item = PyList_GetItem(list, 0);
|
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|
|
|
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|
Py_INCREF(item);
|
2007-12-02 19:08:39 -04:00
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|
PyList_SetItem(list, 1, PyLong_FromLong(0L));
|
2007-08-15 11:28:22 -03:00
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|
PyObject_Print(item, stdout, 0);
|
|
|
|
Py_DECREF(item);
|
|
|
|
}
|
|
|
|
|
|
|
|
This is a true story. An older version of Python contained variants of this bug
|
|
|
|
and someone spent a considerable amount of time in a C debugger to figure out
|
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|
|
why his :meth:`__del__` methods would fail...
|
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|
|
|
|
The second case of problems with a borrowed reference is a variant involving
|
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|
|
threads. Normally, multiple threads in the Python interpreter can't get in each
|
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|
|
other's way, because there is a global lock protecting Python's entire object
|
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|
|
space. However, it is possible to temporarily release this lock using the macro
|
2010-10-06 07:11:56 -03:00
|
|
|
:c:macro:`Py_BEGIN_ALLOW_THREADS`, and to re-acquire it using
|
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|
|
:c:macro:`Py_END_ALLOW_THREADS`. This is common around blocking I/O calls, to
|
2007-08-15 11:28:22 -03:00
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|
|
let other threads use the processor while waiting for the I/O to complete.
|
|
|
|
Obviously, the following function has the same problem as the previous one::
|
|
|
|
|
|
|
|
void
|
|
|
|
bug(PyObject *list)
|
|
|
|
{
|
|
|
|
PyObject *item = PyList_GetItem(list, 0);
|
|
|
|
Py_BEGIN_ALLOW_THREADS
|
|
|
|
...some blocking I/O call...
|
|
|
|
Py_END_ALLOW_THREADS
|
|
|
|
PyObject_Print(item, stdout, 0); /* BUG! */
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
.. _nullpointers:
|
|
|
|
|
|
|
|
NULL Pointers
|
|
|
|
-------------
|
|
|
|
|
|
|
|
In general, functions that take object references as arguments do not expect you
|
|
|
|
to pass them *NULL* pointers, and will dump core (or cause later core dumps) if
|
|
|
|
you do so. Functions that return object references generally return *NULL* only
|
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|
|
to indicate that an exception occurred. The reason for not testing for *NULL*
|
|
|
|
arguments is that functions often pass the objects they receive on to other
|
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|
function --- if each function were to test for *NULL*, there would be a lot of
|
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|
|
redundant tests and the code would run more slowly.
|
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|
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|
It is better to test for *NULL* only at the "source:" when a pointer that may be
|
2010-10-06 07:11:56 -03:00
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|
*NULL* is received, for example, from :c:func:`malloc` or from a function that
|
2007-08-15 11:28:22 -03:00
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|
may raise an exception.
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|
2010-10-06 07:11:56 -03:00
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|
The macros :c:func:`Py_INCREF` and :c:func:`Py_DECREF` do not check for *NULL*
|
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|
pointers --- however, their variants :c:func:`Py_XINCREF` and :c:func:`Py_XDECREF`
|
2007-08-15 11:28:22 -03:00
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do.
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|
The macros for checking for a particular object type (``Pytype_Check()``) don't
|
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check for *NULL* pointers --- again, there is much code that calls several of
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these in a row to test an object against various different expected types, and
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this would generate redundant tests. There are no variants with *NULL*
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checking.
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The C function calling mechanism guarantees that the argument list passed to C
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functions (``args`` in the examples) is never *NULL* --- in fact it guarantees
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that it is always a tuple. [#]_
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It is a severe error to ever let a *NULL* pointer "escape" to the Python user.
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Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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.. Frank Stajano:
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A pedagogically buggy example, along the lines of the previous listing, would
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be helpful here -- showing in more concrete terms what sort of actions could
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cause the problem. I can't very well imagine it from the description.
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2007-08-15 11:28:22 -03:00
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.. _cplusplus:
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Writing Extensions in C++
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=========================
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It is possible to write extension modules in C++. Some restrictions apply. If
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the main program (the Python interpreter) is compiled and linked by the C
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compiler, global or static objects with constructors cannot be used. This is
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not a problem if the main program is linked by the C++ compiler. Functions that
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will be called by the Python interpreter (in particular, module initialization
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functions) have to be declared using ``extern "C"``. It is unnecessary to
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enclose the Python header files in ``extern "C" {...}`` --- they use this form
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already if the symbol ``__cplusplus`` is defined (all recent C++ compilers
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define this symbol).
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2009-05-05 19:31:58 -03:00
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.. _using-capsules:
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2007-08-15 11:28:22 -03:00
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Providing a C API for an Extension Module
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=========================================
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.. sectionauthor:: Konrad Hinsen <hinsen@cnrs-orleans.fr>
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Many extension modules just provide new functions and types to be used from
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Python, but sometimes the code in an extension module can be useful for other
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extension modules. For example, an extension module could implement a type
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"collection" which works like lists without order. Just like the standard Python
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list type has a C API which permits extension modules to create and manipulate
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lists, this new collection type should have a set of C functions for direct
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manipulation from other extension modules.
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At first sight this seems easy: just write the functions (without declaring them
|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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``static``, of course), provide an appropriate header file, and document
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2007-08-15 11:28:22 -03:00
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the C API. And in fact this would work if all extension modules were always
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linked statically with the Python interpreter. When modules are used as shared
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libraries, however, the symbols defined in one module may not be visible to
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another module. The details of visibility depend on the operating system; some
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systems use one global namespace for the Python interpreter and all extension
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modules (Windows, for example), whereas others require an explicit list of
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imported symbols at module link time (AIX is one example), or offer a choice of
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different strategies (most Unices). And even if symbols are globally visible,
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the module whose functions one wishes to call might not have been loaded yet!
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Portability therefore requires not to make any assumptions about symbol
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visibility. This means that all symbols in extension modules should be declared
|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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``static``, except for the module's initialization function, in order to
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2007-08-15 11:28:22 -03:00
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avoid name clashes with other extension modules (as discussed in section
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:ref:`methodtable`). And it means that symbols that *should* be accessible from
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other extension modules must be exported in a different way.
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Python provides a special mechanism to pass C-level information (pointers) from
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2009-05-05 19:31:58 -03:00
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one extension module to another one: Capsules. A Capsule is a Python data type
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2010-10-06 07:11:56 -03:00
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which stores a pointer (:c:type:`void \*`). Capsules can only be created and
|
2007-08-15 11:28:22 -03:00
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accessed via their C API, but they can be passed around like any other Python
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object. In particular, they can be assigned to a name in an extension module's
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namespace. Other extension modules can then import this module, retrieve the
|
2009-05-05 19:31:58 -03:00
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value of this name, and then retrieve the pointer from the Capsule.
|
2007-08-15 11:28:22 -03:00
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|
2009-05-05 19:31:58 -03:00
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There are many ways in which Capsules can be used to export the C API of an
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|
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extension module. Each function could get its own Capsule, or all C API pointers
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|
|
could be stored in an array whose address is published in a Capsule. And the
|
2007-08-15 11:28:22 -03:00
|
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|
various tasks of storing and retrieving the pointers can be distributed in
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|
|
different ways between the module providing the code and the client modules.
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|
2009-05-05 19:31:58 -03:00
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Whichever method you choose, it's important to name your Capsules properly.
|
2010-10-06 07:11:56 -03:00
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|
The function :c:func:`PyCapsule_New` takes a name parameter
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|
(:c:type:`const char \*`); you're permitted to pass in a *NULL* name, but
|
2009-05-05 19:31:58 -03:00
|
|
|
we strongly encourage you to specify a name. Properly named Capsules provide
|
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|
|
a degree of runtime type-safety; there is no feasible way to tell one unnamed
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|
|
Capsule from another.
|
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|
|
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|
In particular, Capsules used to expose C APIs should be given a name following
|
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|
|
this convention::
|
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|
|
|
|
|
|
modulename.attributename
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|
|
2010-10-06 07:11:56 -03:00
|
|
|
The convenience function :c:func:`PyCapsule_Import` makes it easy to
|
2009-05-05 19:31:58 -03:00
|
|
|
load a C API provided via a Capsule, but only if the Capsule's name
|
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|
|
matches this convention. This behavior gives C API users a high degree
|
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|
|
of certainty that the Capsule they load contains the correct C API.
|
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|
|
|
2007-08-15 11:28:22 -03:00
|
|
|
The following example demonstrates an approach that puts most of the burden on
|
|
|
|
the writer of the exporting module, which is appropriate for commonly used
|
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|
|
library modules. It stores all C API pointers (just one in the example!) in an
|
2010-10-06 07:11:56 -03:00
|
|
|
array of :c:type:`void` pointers which becomes the value of a Capsule. The header
|
2007-08-15 11:28:22 -03:00
|
|
|
file corresponding to the module provides a macro that takes care of importing
|
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|
|
the module and retrieving its C API pointers; client modules only have to call
|
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|
|
this macro before accessing the C API.
|
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|
|
|
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|
|
The exporting module is a modification of the :mod:`spam` module from section
|
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|
|
:ref:`extending-simpleexample`. The function :func:`spam.system` does not call
|
2010-10-06 07:11:56 -03:00
|
|
|
the C library function :c:func:`system` directly, but a function
|
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|
|
:c:func:`PySpam_System`, which would of course do something more complicated in
|
2007-08-15 11:28:22 -03:00
|
|
|
reality (such as adding "spam" to every command). This function
|
2010-10-06 07:11:56 -03:00
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|
:c:func:`PySpam_System` is also exported to other extension modules.
|
2007-08-15 11:28:22 -03:00
|
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|
2010-10-06 07:11:56 -03:00
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The function :c:func:`PySpam_System` is a plain C function, declared
|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
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|
``static`` like everything else::
|
2007-08-15 11:28:22 -03:00
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|
|
static int
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|
|
PySpam_System(const char *command)
|
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|
|
{
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|
|
return system(command);
|
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|
|
}
|
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|
|
2010-10-06 07:11:56 -03:00
|
|
|
The function :c:func:`spam_system` is modified in a trivial way::
|
2007-08-15 11:28:22 -03:00
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|
|
static PyObject *
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|
|
spam_system(PyObject *self, PyObject *args)
|
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|
|
{
|
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|
|
const char *command;
|
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|
|
int sts;
|
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|
|
|
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|
|
if (!PyArg_ParseTuple(args, "s", &command))
|
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|
|
return NULL;
|
|
|
|
sts = PySpam_System(command);
|
2010-11-26 07:55:48 -04:00
|
|
|
return PyLong_FromLong(sts);
|
2007-08-15 11:28:22 -03:00
|
|
|
}
|
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|
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|
|
In the beginning of the module, right after the line ::
|
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|
|
|
|
|
|
#include "Python.h"
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|
|
|
|
|
|
two more lines must be added::
|
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|
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|
#define SPAM_MODULE
|
|
|
|
#include "spammodule.h"
|
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|
|
The ``#define`` is used to tell the header file that it is being included in the
|
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|
|
exporting module, not a client module. Finally, the module's initialization
|
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|
|
function must take care of initializing the C API pointer array::
|
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|
|
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|
PyMODINIT_FUNC
|
2008-06-11 02:26:20 -03:00
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|
PyInit_spam(void)
|
2007-08-15 11:28:22 -03:00
|
|
|
{
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|
|
PyObject *m;
|
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|
|
static void *PySpam_API[PySpam_API_pointers];
|
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|
|
PyObject *c_api_object;
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|
2008-06-11 02:26:20 -03:00
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|
m = PyModule_Create(&spammodule);
|
2007-08-15 11:28:22 -03:00
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|
if (m == NULL)
|
2008-06-11 02:26:20 -03:00
|
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|
return NULL;
|
2007-08-15 11:28:22 -03:00
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|
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|
/* Initialize the C API pointer array */
|
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|
|
PySpam_API[PySpam_System_NUM] = (void *)PySpam_System;
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|
2009-05-05 19:31:58 -03:00
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|
/* Create a Capsule containing the API pointer array's address */
|
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|
|
c_api_object = PyCapsule_New((void *)PySpam_API, "spam._C_API", NULL);
|
2007-08-15 11:28:22 -03:00
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|
if (c_api_object != NULL)
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|
PyModule_AddObject(m, "_C_API", c_api_object);
|
2008-06-11 02:26:20 -03:00
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|
return m;
|
2007-08-15 11:28:22 -03:00
|
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|
}
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|
Merged revisions 59605-59624 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r59606 | georg.brandl | 2007-12-29 11:57:00 +0100 (Sat, 29 Dec 2007) | 2 lines
Some cleanup in the docs.
........
r59611 | martin.v.loewis | 2007-12-29 19:49:21 +0100 (Sat, 29 Dec 2007) | 2 lines
Bug #1699: Define _BSD_SOURCE only on OpenBSD.
........
r59612 | raymond.hettinger | 2007-12-29 23:09:34 +0100 (Sat, 29 Dec 2007) | 1 line
Simpler documentation for itertools.tee(). Should be backported.
........
r59613 | raymond.hettinger | 2007-12-29 23:16:24 +0100 (Sat, 29 Dec 2007) | 1 line
Improve docs for itertools.groupby(). The use of xrange(0) to create a unique object is less obvious than object().
........
r59620 | christian.heimes | 2007-12-31 15:47:07 +0100 (Mon, 31 Dec 2007) | 3 lines
Added wininst-9.0.exe executable for VS 2008
Integrated bdist_wininst into PCBuild9 directory
........
r59621 | christian.heimes | 2007-12-31 15:51:18 +0100 (Mon, 31 Dec 2007) | 1 line
Moved PCbuild directory to PC/VS7.1
........
r59622 | christian.heimes | 2007-12-31 15:59:26 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot
........
r59623 | christian.heimes | 2007-12-31 16:02:41 +0100 (Mon, 31 Dec 2007) | 1 line
Fix paths for build bot, part 2
........
r59624 | christian.heimes | 2007-12-31 16:18:55 +0100 (Mon, 31 Dec 2007) | 1 line
Renamed PCBuild9 directory to PCBuild
........
2007-12-31 12:14:33 -04:00
|
|
|
Note that ``PySpam_API`` is declared ``static``; otherwise the pointer
|
2008-06-11 02:26:20 -03:00
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|
array would disappear when :func:`PyInit_spam` terminates!
|
2007-08-15 11:28:22 -03:00
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|
|
The bulk of the work is in the header file :file:`spammodule.h`, which looks
|
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|
|
like this::
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|
#ifndef Py_SPAMMODULE_H
|
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|
#define Py_SPAMMODULE_H
|
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Header file for spammodule */
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/* C API functions */
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|
#define PySpam_System_NUM 0
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|
#define PySpam_System_RETURN int
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|
#define PySpam_System_PROTO (const char *command)
|
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|
/* Total number of C API pointers */
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|
#define PySpam_API_pointers 1
|
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|
#ifdef SPAM_MODULE
|
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|
/* This section is used when compiling spammodule.c */
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|
static PySpam_System_RETURN PySpam_System PySpam_System_PROTO;
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|
#else
|
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|
/* This section is used in modules that use spammodule's API */
|
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|
static void **PySpam_API;
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|
#define PySpam_System \
|
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|
(*(PySpam_System_RETURN (*)PySpam_System_PROTO) PySpam_API[PySpam_System_NUM])
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|
2009-05-05 19:31:58 -03:00
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|
/* Return -1 on error, 0 on success.
|
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* PyCapsule_Import will set an exception if there's an error.
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*/
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2007-08-15 11:28:22 -03:00
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static int
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import_spam(void)
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{
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2009-05-05 19:31:58 -03:00
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PySpam_API = (void **)PyCapsule_Import("spam._C_API", 0);
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return (PySpam_API != NULL) ? 0 : -1;
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2007-08-15 11:28:22 -03:00
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}
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* !defined(Py_SPAMMODULE_H) */
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All that a client module must do in order to have access to the function
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2010-10-06 07:11:56 -03:00
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:c:func:`PySpam_System` is to call the function (or rather macro)
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:c:func:`import_spam` in its initialization function::
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2007-08-15 11:28:22 -03:00
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PyMODINIT_FUNC
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2009-03-23 22:40:39 -03:00
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PyInit_client(void)
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2007-08-15 11:28:22 -03:00
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{
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PyObject *m;
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2009-03-31 12:52:41 -03:00
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m = PyModule_Create(&clientmodule);
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2007-08-15 11:28:22 -03:00
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if (m == NULL)
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2009-03-31 12:52:41 -03:00
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return NULL;
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2007-08-15 11:28:22 -03:00
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if (import_spam() < 0)
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2009-03-31 12:52:41 -03:00
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return NULL;
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2007-08-15 11:28:22 -03:00
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|
/* additional initialization can happen here */
|
2009-03-31 12:52:41 -03:00
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return m;
|
2007-08-15 11:28:22 -03:00
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}
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The main disadvantage of this approach is that the file :file:`spammodule.h` is
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rather complicated. However, the basic structure is the same for each function
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that is exported, so it has to be learned only once.
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|
2009-05-05 19:31:58 -03:00
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Finally it should be mentioned that Capsules offer additional functionality,
|
2007-08-15 11:28:22 -03:00
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which is especially useful for memory allocation and deallocation of the pointer
|
2009-05-05 19:31:58 -03:00
|
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|
stored in a Capsule. The details are described in the Python/C API Reference
|
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|
Manual in the section :ref:`capsules` and in the implementation of Capsules (files
|
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|
:file:`Include/pycapsule.h` and :file:`Objects/pycapsule.c` in the Python source
|
2007-08-15 11:28:22 -03:00
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code distribution).
|
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.. rubric:: Footnotes
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.. [#] An interface for this function already exists in the standard module :mod:`os`
|
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--- it was chosen as a simple and straightforward example.
|
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.. [#] The metaphor of "borrowing" a reference is not completely correct: the owner
|
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|
still has a copy of the reference.
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.. [#] Checking that the reference count is at least 1 **does not work** --- the
|
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|
reference count itself could be in freed memory and may thus be reused for
|
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|
another object!
|
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.. [#] These guarantees don't hold when you use the "old" style calling convention ---
|
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|
this is still found in much existing code.
|