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| author | Georg Brandl <georg@python.org> | 2008-01-20 09:30:57 (GMT) |
|---|---|---|
| committer | Georg Brandl <georg@python.org> | 2008-01-20 09:30:57 (GMT) |
| commit | 54a3faae0806ab1dd8290e16acc8ab7acdd4762b (patch) | |
| tree | 3f58890aaea549244ca64e911f8deee3ca5bd08d /Doc/c-api/concrete.rst | |
| parent | 135bf209ac9a44244a97fd3bf5ff638a320e1a43 (diff) | |
| download | cpython-54a3faae0806ab1dd8290e16acc8ab7acdd4762b.zip cpython-54a3faae0806ab1dd8290e16acc8ab7acdd4762b.tar.gz cpython-54a3faae0806ab1dd8290e16acc8ab7acdd4762b.tar.bz2 | |
Split C API docs in Py3k branch.
Diffstat (limited to 'Doc/c-api/concrete.rst')
| -rw-r--r-- | Doc/c-api/concrete.rst | 3361 |
1 files changed, 31 insertions, 3330 deletions
diff --git a/Doc/c-api/concrete.rst b/Doc/c-api/concrete.rst index 343223c..a0dfe21 100644 --- a/Doc/c-api/concrete.rst +++ b/Doc/c-api/concrete.rst @@ -29,99 +29,10 @@ Fundamental Objects This section describes Python type objects and the singleton object ``None``. +.. toctree:: -.. _typeobjects: - -Type Objects ------------- - -.. index:: object: type - - -.. ctype:: PyTypeObject - - The C structure of the objects used to describe built-in types. - - -.. cvar:: PyObject* PyType_Type - - .. index:: single: TypeType (in module types) - - This is the type object for type objects; it is the same object as ``type`` and - ``types.TypeType`` in the Python layer. - - -.. cfunction:: int PyType_Check(PyObject *o) - - Return true if the object *o* is a type object, including instances of types - derived from the standard type object. Return false in all other cases. - - -.. cfunction:: int PyType_CheckExact(PyObject *o) - - Return true if the object *o* is a type object, but not a subtype of the - standard type object. Return false in all other cases. - - -.. cfunction:: int PyType_HasFeature(PyObject *o, int feature) - - Return true if the type object *o* sets the feature *feature*. Type features - are denoted by single bit flags. - - -.. cfunction:: int PyType_IS_GC(PyObject *o) - - Return true if the type object includes support for the cycle detector; this - tests the type flag :const:`Py_TPFLAGS_HAVE_GC`. - - -.. cfunction:: int PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b) - - Return true if *a* is a subtype of *b*. - - -.. cfunction:: PyObject* PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems) - - XXX: Document. - - -.. cfunction:: PyObject* PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds) - - XXX: Document. - - -.. cfunction:: int PyType_Ready(PyTypeObject *type) - - Finalize a type object. This should be called on all type objects to finish - their initialization. This function is responsible for adding inherited slots - from a type's base class. Return ``0`` on success, or return ``-1`` and sets an - exception on error. - - -.. _noneobject: - -The None Object ---------------- - -.. index:: object: None - -Note that the :ctype:`PyTypeObject` for ``None`` is not directly exposed in the -Python/C API. Since ``None`` is a singleton, testing for object identity (using -``==`` in C) is sufficient. There is no :cfunc:`PyNone_Check` function for the -same reason. - - -.. cvar:: PyObject* Py_None - - The Python ``None`` object, denoting lack of value. This object has no methods. - It needs to be treated just like any other object with respect to reference - counts. - - -.. cmacro:: Py_RETURN_NONE - - Properly handle returning :cdata:`Py_None` from within a C function (that is, - increment the reference count of None and return it.) + type.rst + none.rst .. _numericobjects: @@ -131,447 +42,12 @@ Numeric Objects .. index:: object: numeric +.. toctree:: -.. _boolobjects: - -Boolean Objects ---------------- - -Booleans in Python are implemented as a subclass of integers. There are only -two booleans, :const:`Py_False` and :const:`Py_True`. As such, the normal -creation and deletion functions don't apply to booleans. The following macros -are available, however. - - -.. cfunction:: int PyBool_Check(PyObject *o) - - Return true if *o* is of type :cdata:`PyBool_Type`. - - -.. cvar:: PyObject* Py_False - - The Python ``False`` object. This object has no methods. It needs to be - treated just like any other object with respect to reference counts. - - -.. cvar:: PyObject* Py_True - - The Python ``True`` object. This object has no methods. It needs to be treated - just like any other object with respect to reference counts. - - -.. cmacro:: Py_RETURN_FALSE - - Return :const:`Py_False` from a function, properly incrementing its reference - count. - - -.. cmacro:: Py_RETURN_TRUE - - Return :const:`Py_True` from a function, properly incrementing its reference - count. - - -.. cfunction:: PyObject* PyBool_FromLong(long v) - - Return a new reference to :const:`Py_True` or :const:`Py_False` depending on the - truth value of *v*. - - -.. _longobjects: - -Integer Objects ---------------- - -.. index:: object: long integer - object: integer - -All integers are implemented as "long" integer objects of arbitrary size. - -.. ctype:: PyLongObject - - This subtype of :ctype:`PyObject` represents a Python integer object. - - -.. cvar:: PyTypeObject PyLong_Type - - This instance of :ctype:`PyTypeObject` represents the Python integer type. - This is the same object as ``int``. - - -.. cfunction:: int PyLong_Check(PyObject *p) - - Return true if its argument is a :ctype:`PyLongObject` or a subtype of - :ctype:`PyLongObject`. - - -.. cfunction:: int PyLong_CheckExact(PyObject *p) - - Return true if its argument is a :ctype:`PyLongObject`, but not a subtype of - :ctype:`PyLongObject`. - - -.. cfunction:: PyObject* PyLong_FromLong(long v) - - Return a new :ctype:`PyLongObject` object from *v*, or *NULL* on failure. - - The current implementation keeps an array of integer objects for all integers - between ``-5`` and ``256``, when you create an int in that range you actually - just get back a reference to the existing object. So it should be possible to - change the value of ``1``. I suspect the behaviour of Python in this case is - undefined. :-) - - -.. cfunction:: PyObject* PyLong_FromUnsignedLong(unsigned long v) - - Return a new :ctype:`PyLongObject` object from a C :ctype:`unsigned long`, or - *NULL* on failure. - - -.. cfunction:: PyObject* PyLong_FromSsize_t(Py_ssize_t v) - - Return a new :ctype:`PyLongObject` object with a value of *v*, or *NULL* - on failure. - - -.. cfunction:: PyObject* PyLong_FromSize_t(size_t v) - - Return a new :ctype:`PyLongObject` object with a value of *v*, or *NULL* - on failure. - - -.. cfunction:: PyObject* PyLong_FromLongLong(PY_LONG_LONG v) - - Return a new :ctype:`PyLongObject` object from a C :ctype:`long long`, or *NULL* - on failure. - - -.. cfunction:: PyObject* PyLong_FromUnsignedLongLong(unsigned PY_LONG_LONG v) - - Return a new :ctype:`PyLongObject` object from a C :ctype:`unsigned long long`, - or *NULL* on failure. - - -.. cfunction:: PyObject* PyLong_FromDouble(double v) - - Return a new :ctype:`PyLongObject` object from the integer part of *v*, or - *NULL* on failure. - - -.. cfunction:: PyObject* PyLong_FromString(char *str, char **pend, int base) - - Return a new :ctype:`PyLongObject` based on the string value in *str*, which - is interpreted according to the radix in *base*. If *pend* is non-*NULL*, - ``*pend`` will point to the first character in *str* which follows the - representation of the number. If *base* is ``0``, the radix will be - determined based on the leading characters of *str*: if *str* starts with - ``'0x'`` or ``'0X'``, radix 16 will be used; if *str* starts with ``'0o'`` or - ``'0O'``, radix 8 will be used; if *str* starts with ``'0b'`` or ``'0B'``, - radix 2 will be used; otherwise radix 10 will be used. If *base* is not - ``0``, it must be between ``2`` and ``36``, inclusive. Leading spaces are - ignored. If there are no digits, :exc:`ValueError` will be raised. - - -.. cfunction:: PyObject* PyLong_FromUnicode(Py_UNICODE *u, Py_ssize_t length, int base) - - Convert a sequence of Unicode digits to a Python integer value. The Unicode - string is first encoded to a byte string using :cfunc:`PyUnicode_EncodeDecimal` - and then converted using :cfunc:`PyLong_FromString`. - - -.. cfunction:: PyObject* PyLong_FromVoidPtr(void *p) - - Create a Python integer from the pointer *p*. The pointer value can be - retrieved from the resulting value using :cfunc:`PyLong_AsVoidPtr`. - - -.. XXX alias PyLong_AS_LONG (for now) -.. cfunction:: long PyLong_AsLong(PyObject *pylong) - - .. index:: - single: LONG_MAX - single: OverflowError (built-in exception) - - Return a C :ctype:`long` representation of the contents of *pylong*. If - *pylong* is greater than :const:`LONG_MAX`, raise an :exc:`OverflowError`, - and return -1. Convert non-long objects automatically to long first, - and return -1 if that raises exceptions. - -.. cfunction:: long PyLong_AsLongAndOverflow(PyObject *pylong, int* overflow) - - Return a C :ctype:`long` representation of the contents of *pylong*. If - *pylong* is greater than :const:`LONG_MAX`, return -1 and - set `*overflow` to 1 (for overflow) or -1 (for underflow). - If an exception is set because of type errors, also return -1. - - -.. cfunction:: unsigned long PyLong_AsUnsignedLong(PyObject *pylong) - - .. index:: - single: ULONG_MAX - single: OverflowError (built-in exception) - - Return a C :ctype:`unsigned long` representation of the contents of *pylong*. - If *pylong* is greater than :const:`ULONG_MAX`, an :exc:`OverflowError` is - raised. - - -.. cfunction:: Py_ssize_t PyLong_AsSsize_t(PyObject *pylong) - - .. index:: - single: PY_SSIZE_T_MAX - - Return a :ctype:`Py_ssize_t` representation of the contents of *pylong*. If - *pylong* is greater than :const:`PY_SSIZE_T_MAX`, an :exc:`OverflowError` is - raised. - - -.. cfunction:: size_t PyLong_AsSize_t(PyObject *pylong) - - Return a :ctype:`size_t` representation of the contents of *pylong*. If - *pylong* is greater than the maximum value for a :ctype:`size_t`, an - :exc:`OverflowError` is raised. - - -.. cfunction:: PY_LONG_LONG PyLong_AsLongLong(PyObject *pylong) - - Return a C :ctype:`long long` from a Python integer. If *pylong* cannot be - represented as a :ctype:`long long`, an :exc:`OverflowError` will be raised. - - -.. cfunction:: unsigned PY_LONG_LONG PyLong_AsUnsignedLongLong(PyObject *pylong) - - Return a C :ctype:`unsigned long long` from a Python integer. If *pylong* - cannot be represented as an :ctype:`unsigned long long`, an :exc:`OverflowError` - will be raised if the value is positive, or a :exc:`TypeError` will be raised if - the value is negative. - - -.. cfunction:: unsigned long PyLong_AsUnsignedLongMask(PyObject *io) - - Return a C :ctype:`unsigned long` from a Python integer, without checking for - overflow. - - -.. cfunction:: unsigned PY_LONG_LONG PyLong_AsUnsignedLongLongMask(PyObject *io) - - Return a C :ctype:`unsigned long long` from a Python integer, without - checking for overflow. - - -.. cfunction:: double PyLong_AsDouble(PyObject *pylong) - - Return a C :ctype:`double` representation of the contents of *pylong*. If - *pylong* cannot be approximately represented as a :ctype:`double`, an - :exc:`OverflowError` exception is raised and ``-1.0`` will be returned. - - -.. cfunction:: void* PyLong_AsVoidPtr(PyObject *pylong) - - Convert a Python integer *pylong* to a C :ctype:`void` pointer. If *pylong* - cannot be converted, an :exc:`OverflowError` will be raised. This is only - assured to produce a usable :ctype:`void` pointer for values created with - :cfunc:`PyLong_FromVoidPtr`. - - -.. _floatobjects: - -Floating Point Objects ----------------------- - -.. index:: object: floating point - - -.. ctype:: PyFloatObject - - This subtype of :ctype:`PyObject` represents a Python floating point object. - - -.. cvar:: PyTypeObject PyFloat_Type - - .. index:: single: FloatType (in modules types) - - This instance of :ctype:`PyTypeObject` represents the Python floating point - type. This is the same object as ``float`` and ``types.FloatType``. - - -.. cfunction:: int PyFloat_Check(PyObject *p) - - Return true if its argument is a :ctype:`PyFloatObject` or a subtype of - :ctype:`PyFloatObject`. - - -.. cfunction:: int PyFloat_CheckExact(PyObject *p) - - Return true if its argument is a :ctype:`PyFloatObject`, but not a subtype of - :ctype:`PyFloatObject`. - - -.. cfunction:: PyObject* PyFloat_FromString(PyObject *str) - - Create a :ctype:`PyFloatObject` object based on the string value in *str*, or - *NULL* on failure. - - -.. cfunction:: PyObject* PyFloat_FromDouble(double v) - - Create a :ctype:`PyFloatObject` object from *v*, or *NULL* on failure. - - -.. cfunction:: double PyFloat_AsDouble(PyObject *pyfloat) - - Return a C :ctype:`double` representation of the contents of *pyfloat*. If - *pyfloat* is not a Python floating point object but has a :meth:`__float__` - method, this method will first be called to convert *pyfloat* into a float. - - -.. cfunction:: double PyFloat_AS_DOUBLE(PyObject *pyfloat) - - Return a C :ctype:`double` representation of the contents of *pyfloat*, but - without error checking. - - -.. cfunction:: PyObject* PyFloat_GetInfo(void) - - Return a structseq instance which contains information about the - precision, minimum and maximum values of a float. It's a thin wrapper - around the header file :file:`float.h`. - - -.. cfunction:: double PyFloat_GetMax(void) - - Return the maximum representable finite float *DBL_MAX* as C :ctype:`double`. - - -.. cfunction:: double PyFloat_GetMin(void) - - Return the minimum normalized positive float *DBL_MIN* as C :ctype:`double`. - - -.. _complexobjects: - -Complex Number Objects ----------------------- - -.. index:: object: complex number - -Python's complex number objects are implemented as two distinct types when -viewed from the C API: one is the Python object exposed to Python programs, and -the other is a C structure which represents the actual complex number value. -The API provides functions for working with both. - - -Complex Numbers as C Structures -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -Note that the functions which accept these structures as parameters and return -them as results do so *by value* rather than dereferencing them through -pointers. This is consistent throughout the API. - - -.. ctype:: Py_complex - - The C structure which corresponds to the value portion of a Python complex - number object. Most of the functions for dealing with complex number objects - use structures of this type as input or output values, as appropriate. It is - defined as:: - - typedef struct { - double real; - double imag; - } Py_complex; - - -.. cfunction:: Py_complex _Py_c_sum(Py_complex left, Py_complex right) - - Return the sum of two complex numbers, using the C :ctype:`Py_complex` - representation. - - -.. cfunction:: Py_complex _Py_c_diff(Py_complex left, Py_complex right) - - Return the difference between two complex numbers, using the C - :ctype:`Py_complex` representation. - - -.. cfunction:: Py_complex _Py_c_neg(Py_complex complex) - - Return the negation of the complex number *complex*, using the C - :ctype:`Py_complex` representation. - - -.. cfunction:: Py_complex _Py_c_prod(Py_complex left, Py_complex right) - - Return the product of two complex numbers, using the C :ctype:`Py_complex` - representation. - - -.. cfunction:: Py_complex _Py_c_quot(Py_complex dividend, Py_complex divisor) - - Return the quotient of two complex numbers, using the C :ctype:`Py_complex` - representation. - - -.. cfunction:: Py_complex _Py_c_pow(Py_complex num, Py_complex exp) - - Return the exponentiation of *num* by *exp*, using the C :ctype:`Py_complex` - representation. - - -Complex Numbers as Python Objects -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - - -.. ctype:: PyComplexObject - - This subtype of :ctype:`PyObject` represents a Python complex number object. - - -.. cvar:: PyTypeObject PyComplex_Type - - This instance of :ctype:`PyTypeObject` represents the Python complex number - type. It is the same object as ``complex`` and ``types.ComplexType``. - - -.. cfunction:: int PyComplex_Check(PyObject *p) - - Return true if its argument is a :ctype:`PyComplexObject` or a subtype of - :ctype:`PyComplexObject`. - - -.. cfunction:: int PyComplex_CheckExact(PyObject *p) - - Return true if its argument is a :ctype:`PyComplexObject`, but not a subtype of - :ctype:`PyComplexObject`. - - -.. cfunction:: PyObject* PyComplex_FromCComplex(Py_complex v) - - Create a new Python complex number object from a C :ctype:`Py_complex` value. - - -.. cfunction:: PyObject* PyComplex_FromDoubles(double real, double imag) - - Return a new :ctype:`PyComplexObject` object from *real* and *imag*. - - -.. cfunction:: double PyComplex_RealAsDouble(PyObject *op) - - Return the real part of *op* as a C :ctype:`double`. - - -.. cfunction:: double PyComplex_ImagAsDouble(PyObject *op) - - Return the imaginary part of *op* as a C :ctype:`double`. - - -.. cfunction:: Py_complex PyComplex_AsCComplex(PyObject *op) - - Return the :ctype:`Py_complex` value of the complex number *op*. - - If *op* is not a Python complex number object but has a :meth:`__complex__` - method, this method will first be called to convert *op* to a Python complex - number object. + long.rst + bool.rst + float.rst + complex.rst .. _sequenceobjects: @@ -587,1515 +63,13 @@ intrinsic to the Python language. .. XXX sort out unicode, str, bytes and bytearray -.. _stringobjects: - -String Objects --------------- - -These functions raise :exc:`TypeError` when expecting a string parameter and are -called with a non-string parameter. - -.. index:: object: string - - -.. ctype:: PyStringObject - - This subtype of :ctype:`PyObject` represents a Python string object. - - -.. cvar:: PyTypeObject PyString_Type - - .. index:: single: StringType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python string type; it is - the same object as ``str`` and ``types.StringType`` in the Python layer. . - - -.. cfunction:: int PyString_Check(PyObject *o) - - Return true if the object *o* is a string object or an instance of a subtype of - the string type. - - -.. cfunction:: int PyString_CheckExact(PyObject *o) - - Return true if the object *o* is a string object, but not an instance of a - subtype of the string type. - - -.. cfunction:: PyObject* PyString_FromString(const char *v) - - Return a new string object with a copy of the string *v* as value on success, - and *NULL* on failure. The parameter *v* must not be *NULL*; it will not be - checked. - - -.. cfunction:: PyObject* PyString_FromStringAndSize(const char *v, Py_ssize_t len) - - Return a new string object with a copy of the string *v* as value and length - *len* on success, and *NULL* on failure. If *v* is *NULL*, the contents of the - string are uninitialized. - - -.. cfunction:: PyObject* PyString_FromFormat(const char *format, ...) - - Take a C :cfunc:`printf`\ -style *format* string and a variable number of - arguments, calculate the size of the resulting Python string and return a string - with the values formatted into it. The variable arguments must be C types and - must correspond exactly to the format characters in the *format* string. The - following format characters are allowed: - - .. % XXX: This should be exactly the same as the table in PyErr_Format. - .. % One should just refer to the other. - .. % XXX: The descriptions for %zd and %zu are wrong, but the truth is complicated - .. % because not all compilers support the %z width modifier -- we fake it - .. % when necessary via interpolating PY_FORMAT_SIZE_T. - .. % %u, %lu, %zu should have "new in Python 2.5" blurbs. - - +-------------------+---------------+--------------------------------+ - | Format Characters | Type | Comment | - +===================+===============+================================+ - | :attr:`%%` | *n/a* | The literal % character. | - +-------------------+---------------+--------------------------------+ - | :attr:`%c` | int | A single character, | - | | | represented as an C int. | - +-------------------+---------------+--------------------------------+ - | :attr:`%d` | int | Exactly equivalent to | - | | | ``printf("%d")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%u` | unsigned int | Exactly equivalent to | - | | | ``printf("%u")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%ld` | long | Exactly equivalent to | - | | | ``printf("%ld")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%lu` | unsigned long | Exactly equivalent to | - | | | ``printf("%lu")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%zd` | Py_ssize_t | Exactly equivalent to | - | | | ``printf("%zd")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%zu` | size_t | Exactly equivalent to | - | | | ``printf("%zu")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%i` | int | Exactly equivalent to | - | | | ``printf("%i")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%x` | int | Exactly equivalent to | - | | | ``printf("%x")``. | - +-------------------+---------------+--------------------------------+ - | :attr:`%s` | char\* | A null-terminated C character | - | | | array. | - +-------------------+---------------+--------------------------------+ - | :attr:`%p` | void\* | The hex representation of a C | - | | | pointer. Mostly equivalent to | - | | | ``printf("%p")`` except that | - | | | it is guaranteed to start with | - | | | the literal ``0x`` regardless | - | | | of what the platform's | - | | | ``printf`` yields. | - +-------------------+---------------+--------------------------------+ - - An unrecognized format character causes all the rest of the format string to be - copied as-is to the result string, and any extra arguments discarded. - - -.. cfunction:: PyObject* PyString_FromFormatV(const char *format, va_list vargs) - - Identical to :func:`PyString_FromFormat` except that it takes exactly two - arguments. - - -.. cfunction:: Py_ssize_t PyString_Size(PyObject *string) - - Return the length of the string in string object *string*. - - -.. cfunction:: Py_ssize_t PyString_GET_SIZE(PyObject *string) - - Macro form of :cfunc:`PyString_Size` but without error checking. - - -.. cfunction:: char* PyString_AsString(PyObject *string) - - Return a NUL-terminated representation of the contents of *string*. The pointer - refers to the internal buffer of *string*, not a copy. The data must not be - modified in any way, unless the string was just created using - ``PyString_FromStringAndSize(NULL, size)``. It must not be deallocated. If - *string* is a Unicode object, this function computes the default encoding of - *string* and operates on that. If *string* is not a string object at all, - :cfunc:`PyString_AsString` returns *NULL* and raises :exc:`TypeError`. - - -.. cfunction:: char* PyString_AS_STRING(PyObject *string) - - Macro form of :cfunc:`PyString_AsString` but without error checking. Only - string objects are supported; no Unicode objects should be passed. - - -.. cfunction:: int PyString_AsStringAndSize(PyObject *obj, char **buffer, Py_ssize_t *length) - - Return a NUL-terminated representation of the contents of the object *obj* - through the output variables *buffer* and *length*. - - The function accepts both string and Unicode objects as input. For Unicode - objects it returns the default encoded version of the object. If *length* is - *NULL*, the resulting buffer may not contain NUL characters; if it does, the - function returns ``-1`` and a :exc:`TypeError` is raised. - - The buffer refers to an internal string buffer of *obj*, not a copy. The data - must not be modified in any way, unless the string was just created using - ``PyString_FromStringAndSize(NULL, size)``. It must not be deallocated. If - *string* is a Unicode object, this function computes the default encoding of - *string* and operates on that. If *string* is not a string object at all, - :cfunc:`PyString_AsStringAndSize` returns ``-1`` and raises :exc:`TypeError`. - - -.. cfunction:: void PyString_Concat(PyObject **string, PyObject *newpart) - - Create a new string object in *\*string* containing the contents of *newpart* - appended to *string*; the caller will own the new reference. The reference to - the old value of *string* will be stolen. If the new string cannot be created, - the old reference to *string* will still be discarded and the value of - *\*string* will be set to *NULL*; the appropriate exception will be set. - - -.. cfunction:: void PyString_ConcatAndDel(PyObject **string, PyObject *newpart) - - Create a new string object in *\*string* containing the contents of *newpart* - appended to *string*. This version decrements the reference count of *newpart*. - - -.. cfunction:: int _PyString_Resize(PyObject **string, Py_ssize_t newsize) - - A way to resize a string object even though it is "immutable". Only use this to - build up a brand new string object; don't use this if the string may already be - known in other parts of the code. It is an error to call this function if the - refcount on the input string object is not one. Pass the address of an existing - string object as an lvalue (it may be written into), and the new size desired. - On success, *\*string* holds the resized string object and ``0`` is returned; - the address in *\*string* may differ from its input value. If the reallocation - fails, the original string object at *\*string* is deallocated, *\*string* is - set to *NULL*, a memory exception is set, and ``-1`` is returned. - - -.. cfunction:: PyObject* PyString_Format(PyObject *format, PyObject *args) - - Return a new string object from *format* and *args*. Analogous to ``format % - args``. The *args* argument must be a tuple. - - -.. cfunction:: void PyString_InternInPlace(PyObject **string) - - Intern the argument *\*string* in place. The argument must be the address of a - pointer variable pointing to a Python string object. If there is an existing - interned string that is the same as *\*string*, it sets *\*string* to it - (decrementing the reference count of the old string object and incrementing the - reference count of the interned string object), otherwise it leaves *\*string* - alone and interns it (incrementing its reference count). (Clarification: even - though there is a lot of talk about reference counts, think of this function as - reference-count-neutral; you own the object after the call if and only if you - owned it before the call.) - - -.. cfunction:: PyObject* PyString_InternFromString(const char *v) - - A combination of :cfunc:`PyString_FromString` and - :cfunc:`PyString_InternInPlace`, returning either a new string object that has - been interned, or a new ("owned") reference to an earlier interned string object - with the same value. - - -.. cfunction:: PyObject* PyString_Decode(const char *s, Py_ssize_t size, const char *encoding, const char *errors) - - Create an object by decoding *size* bytes of the encoded buffer *s* using the - codec registered for *encoding*. *encoding* and *errors* have the same meaning - as the parameters of the same name in the :func:`unicode` built-in function. - The codec to be used is looked up using the Python codec registry. Return - *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyString_AsDecodedObject(PyObject *str, const char *encoding, const char *errors) - - Decode a string object by passing it to the codec registered for *encoding* and - return the result as Python object. *encoding* and *errors* have the same - meaning as the parameters of the same name in the string :meth:`encode` method. - The codec to be used is looked up using the Python codec registry. Return *NULL* - if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyString_AsEncodedObject(PyObject *str, const char *encoding, const char *errors) - - Encode a string object using the codec registered for *encoding* and return the - result as Python object. *encoding* and *errors* have the same meaning as the - parameters of the same name in the string :meth:`encode` method. The codec to be - used is looked up using the Python codec registry. Return *NULL* if an exception - was raised by the codec. - - -.. _unicodeobjects: - -Unicode Objects ---------------- - -.. sectionauthor:: Marc-Andre Lemburg <mal@lemburg.com> - - -These are the basic Unicode object types used for the Unicode implementation in -Python: - -.. % --- Unicode Type ------------------------------------------------------- - - -.. ctype:: Py_UNICODE - - This type represents the storage type which is used by Python internally as - basis for holding Unicode ordinals. Python's default builds use a 16-bit type - for :ctype:`Py_UNICODE` and store Unicode values internally as UCS2. It is also - possible to build a UCS4 version of Python (most recent Linux distributions come - with UCS4 builds of Python). These builds then use a 32-bit type for - :ctype:`Py_UNICODE` and store Unicode data internally as UCS4. On platforms - where :ctype:`wchar_t` is available and compatible with the chosen Python - Unicode build variant, :ctype:`Py_UNICODE` is a typedef alias for - :ctype:`wchar_t` to enhance native platform compatibility. On all other - platforms, :ctype:`Py_UNICODE` is a typedef alias for either :ctype:`unsigned - short` (UCS2) or :ctype:`unsigned long` (UCS4). - -Note that UCS2 and UCS4 Python builds are not binary compatible. Please keep -this in mind when writing extensions or interfaces. - - -.. ctype:: PyUnicodeObject - - This subtype of :ctype:`PyObject` represents a Python Unicode object. - - -.. cvar:: PyTypeObject PyUnicode_Type - - This instance of :ctype:`PyTypeObject` represents the Python Unicode type. It - is exposed to Python code as ``str``. - -The following APIs are really C macros and can be used to do fast checks and to -access internal read-only data of Unicode objects: - - -.. cfunction:: int PyUnicode_Check(PyObject *o) - - Return true if the object *o* is a Unicode object or an instance of a Unicode - subtype. - - -.. cfunction:: int PyUnicode_CheckExact(PyObject *o) - - Return true if the object *o* is a Unicode object, but not an instance of a - subtype. - - -.. cfunction:: Py_ssize_t PyUnicode_GET_SIZE(PyObject *o) - - Return the size of the object. *o* has to be a :ctype:`PyUnicodeObject` (not - checked). - - -.. cfunction:: Py_ssize_t PyUnicode_GET_DATA_SIZE(PyObject *o) - - Return the size of the object's internal buffer in bytes. *o* has to be a - :ctype:`PyUnicodeObject` (not checked). - - -.. cfunction:: Py_UNICODE* PyUnicode_AS_UNICODE(PyObject *o) - - Return a pointer to the internal :ctype:`Py_UNICODE` buffer of the object. *o* - has to be a :ctype:`PyUnicodeObject` (not checked). - - -.. cfunction:: const char* PyUnicode_AS_DATA(PyObject *o) - - Return a pointer to the internal buffer of the object. *o* has to be a - :ctype:`PyUnicodeObject` (not checked). - -Unicode provides many different character properties. The most often needed ones -are available through these macros which are mapped to C functions depending on -the Python configuration. - -.. % --- Unicode character properties --------------------------------------- - - -.. cfunction:: int Py_UNICODE_ISSPACE(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a whitespace character. - - -.. cfunction:: int Py_UNICODE_ISLOWER(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a lowercase character. - - -.. cfunction:: int Py_UNICODE_ISUPPER(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is an uppercase character. - - -.. cfunction:: int Py_UNICODE_ISTITLE(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a titlecase character. - - -.. cfunction:: int Py_UNICODE_ISLINEBREAK(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a linebreak character. - - -.. cfunction:: int Py_UNICODE_ISDECIMAL(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a decimal character. - - -.. cfunction:: int Py_UNICODE_ISDIGIT(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a digit character. - - -.. cfunction:: int Py_UNICODE_ISNUMERIC(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is a numeric character. - - -.. cfunction:: int Py_UNICODE_ISALPHA(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is an alphabetic character. - - -.. cfunction:: int Py_UNICODE_ISALNUM(Py_UNICODE ch) - - Return 1 or 0 depending on whether *ch* is an alphanumeric character. - -These APIs can be used for fast direct character conversions: - - -.. cfunction:: Py_UNICODE Py_UNICODE_TOLOWER(Py_UNICODE ch) - - Return the character *ch* converted to lower case. - - -.. cfunction:: Py_UNICODE Py_UNICODE_TOUPPER(Py_UNICODE ch) - - Return the character *ch* converted to upper case. - - -.. cfunction:: Py_UNICODE Py_UNICODE_TOTITLE(Py_UNICODE ch) - - Return the character *ch* converted to title case. - - -.. cfunction:: int Py_UNICODE_TODECIMAL(Py_UNICODE ch) - - Return the character *ch* converted to a decimal positive integer. Return - ``-1`` if this is not possible. This macro does not raise exceptions. - - -.. cfunction:: int Py_UNICODE_TODIGIT(Py_UNICODE ch) - - Return the character *ch* converted to a single digit integer. Return ``-1`` if - this is not possible. This macro does not raise exceptions. - - -.. cfunction:: double Py_UNICODE_TONUMERIC(Py_UNICODE ch) - - Return the character *ch* converted to a double. Return ``-1.0`` if this is not - possible. This macro does not raise exceptions. - -To create Unicode objects and access their basic sequence properties, use these -APIs: - -.. % --- Plain Py_UNICODE --------------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_FromUnicode(const Py_UNICODE *u, Py_ssize_t size) - - Create a Unicode Object from the Py_UNICODE buffer *u* of the given size. *u* - may be *NULL* which causes the contents to be undefined. It is the user's - responsibility to fill in the needed data. The buffer is copied into the new - object. If the buffer is not *NULL*, the return value might be a shared object. - Therefore, modification of the resulting Unicode object is only allowed when *u* - is *NULL*. - - -.. cfunction:: PyObject* PyUnicode_FromStringAndSize(const char *u, Py_ssize_t size) - - Create a Unicode Object from the char buffer *u*. The bytes will be interpreted - as being UTF-8 encoded. *u* may also be *NULL* which - causes the contents to be undefined. It is the user's responsibility to fill in - the needed data. The buffer is copied into the new object. If the buffer is not - *NULL*, the return value might be a shared object. Therefore, modification of - the resulting Unicode object is only allowed when *u* is *NULL*. - - -.. cfunction:: PyObject *PyUnicode_FromString(const char *u) - - Create a Unicode object from an UTF-8 encoded null-terminated char buffer - *u*. - - -.. cfunction:: PyObject* PyUnicode_FromFormat(const char *format, ...) - - Take a C :cfunc:`printf`\ -style *format* string and a variable number of - arguments, calculate the size of the resulting Python unicode string and return - a string with the values formatted into it. The variable arguments must be C - types and must correspond exactly to the format characters in the *format* - string. The following format characters are allowed: - - .. % The descriptions for %zd and %zu are wrong, but the truth is complicated - .. % because not all compilers support the %z width modifier -- we fake it - .. % when necessary via interpolating PY_FORMAT_SIZE_T. - - +-------------------+---------------------+--------------------------------+ - | Format Characters | Type | Comment | - +===================+=====================+================================+ - | :attr:`%%` | *n/a* | The literal % character. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%c` | int | A single character, | - | | | represented as an C int. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%d` | int | Exactly equivalent to | - | | | ``printf("%d")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%u` | unsigned int | Exactly equivalent to | - | | | ``printf("%u")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%ld` | long | Exactly equivalent to | - | | | ``printf("%ld")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%lu` | unsigned long | Exactly equivalent to | - | | | ``printf("%lu")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%zd` | Py_ssize_t | Exactly equivalent to | - | | | ``printf("%zd")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%zu` | size_t | Exactly equivalent to | - | | | ``printf("%zu")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%i` | int | Exactly equivalent to | - | | | ``printf("%i")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%x` | int | Exactly equivalent to | - | | | ``printf("%x")``. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%s` | char\* | A null-terminated C character | - | | | array. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%p` | void\* | The hex representation of a C | - | | | pointer. Mostly equivalent to | - | | | ``printf("%p")`` except that | - | | | it is guaranteed to start with | - | | | the literal ``0x`` regardless | - | | | of what the platform's | - | | | ``printf`` yields. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%U` | PyObject\* | A unicode object. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%V` | PyObject\*, char \* | A unicode object (which may be | - | | | *NULL*) and a null-terminated | - | | | C character array as a second | - | | | parameter (which will be used, | - | | | if the first parameter is | - | | | *NULL*). | - +-------------------+---------------------+--------------------------------+ - | :attr:`%S` | PyObject\* | The result of calling | - | | | :func:`PyObject_Unicode`. | - +-------------------+---------------------+--------------------------------+ - | :attr:`%R` | PyObject\* | The result of calling | - | | | :func:`PyObject_Repr`. | - +-------------------+---------------------+--------------------------------+ - - An unrecognized format character causes all the rest of the format string to be - copied as-is to the result string, and any extra arguments discarded. - - -.. cfunction:: PyObject* PyUnicode_FromFormatV(const char *format, va_list vargs) - - Identical to :func:`PyUnicode_FromFormat` except that it takes exactly two - arguments. - - -.. cfunction:: Py_UNICODE* PyUnicode_AsUnicode(PyObject *unicode) - - Return a read-only pointer to the Unicode object's internal :ctype:`Py_UNICODE` - buffer, *NULL* if *unicode* is not a Unicode object. - - -.. cfunction:: Py_ssize_t PyUnicode_GetSize(PyObject *unicode) - - Return the length of the Unicode object. - - -.. cfunction:: PyObject* PyUnicode_FromEncodedObject(PyObject *obj, const char *encoding, const char *errors) - - Coerce an encoded object *obj* to an Unicode object and return a reference with - incremented refcount. - - String and other char buffer compatible objects are decoded according to the - given encoding and using the error handling defined by errors. Both can be - *NULL* to have the interface use the default values (see the next section for - details). - - All other objects, including Unicode objects, cause a :exc:`TypeError` to be - set. - - The API returns *NULL* if there was an error. The caller is responsible for - decref'ing the returned objects. - - -.. cfunction:: PyObject* PyUnicode_FromObject(PyObject *obj) - - Shortcut for ``PyUnicode_FromEncodedObject(obj, NULL, "strict")`` which is used - throughout the interpreter whenever coercion to Unicode is needed. - -If the platform supports :ctype:`wchar_t` and provides a header file wchar.h, -Python can interface directly to this type using the following functions. -Support is optimized if Python's own :ctype:`Py_UNICODE` type is identical to -the system's :ctype:`wchar_t`. - -.. % --- wchar_t support for platforms which support it --------------------- - - -.. cfunction:: PyObject* PyUnicode_FromWideChar(const wchar_t *w, Py_ssize_t size) - - Create a Unicode object from the :ctype:`wchar_t` buffer *w* of the given size. - Return *NULL* on failure. - - -.. cfunction:: Py_ssize_t PyUnicode_AsWideChar(PyUnicodeObject *unicode, wchar_t *w, Py_ssize_t size) - - Copy the Unicode object contents into the :ctype:`wchar_t` buffer *w*. At most - *size* :ctype:`wchar_t` characters are copied (excluding a possibly trailing - 0-termination character). Return the number of :ctype:`wchar_t` characters - copied or -1 in case of an error. Note that the resulting :ctype:`wchar_t` - string may or may not be 0-terminated. It is the responsibility of the caller - to make sure that the :ctype:`wchar_t` string is 0-terminated in case this is - required by the application. - - -.. _builtincodecs: - -Built-in Codecs -^^^^^^^^^^^^^^^ - -Python provides a set of builtin codecs which are written in C for speed. All of -these codecs are directly usable via the following functions. - -Many of the following APIs take two arguments encoding and errors. These -parameters encoding and errors have the same semantics as the ones of the -builtin unicode() Unicode object constructor. - -Setting encoding to *NULL* causes the default encoding to be used which is -ASCII. The file system calls should use :cdata:`Py_FileSystemDefaultEncoding` -as the encoding for file names. This variable should be treated as read-only: On -some systems, it will be a pointer to a static string, on others, it will change -at run-time (such as when the application invokes setlocale). - -Error handling is set by errors which may also be set to *NULL* meaning to use -the default handling defined for the codec. Default error handling for all -builtin codecs is "strict" (:exc:`ValueError` is raised). - -The codecs all use a similar interface. Only deviation from the following -generic ones are documented for simplicity. - -These are the generic codec APIs: - -.. % --- Generic Codecs ----------------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_Decode(const char *s, Py_ssize_t size, const char *encoding, const char *errors) - - Create a Unicode object by decoding *size* bytes of the encoded string *s*. - *encoding* and *errors* have the same meaning as the parameters of the same name - in the :func:`unicode` builtin function. The codec to be used is looked up - using the Python codec registry. Return *NULL* if an exception was raised by - the codec. - - -.. cfunction:: PyObject* PyUnicode_Encode(const Py_UNICODE *s, Py_ssize_t size, const char *encoding, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size and return a Python - string object. *encoding* and *errors* have the same meaning as the parameters - of the same name in the Unicode :meth:`encode` method. The codec to be used is - looked up using the Python codec registry. Return *NULL* if an exception was - raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsEncodedString(PyObject *unicode, const char *encoding, const char *errors) - - Encode a Unicode object and return the result as Python string object. - *encoding* and *errors* have the same meaning as the parameters of the same name - in the Unicode :meth:`encode` method. The codec to be used is looked up using - the Python codec registry. Return *NULL* if an exception was raised by the - codec. - -These are the UTF-8 codec APIs: - -.. % --- UTF-8 Codecs ------------------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_DecodeUTF8(const char *s, Py_ssize_t size, const char *errors) - - Create a Unicode object by decoding *size* bytes of the UTF-8 encoded string - *s*. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_DecodeUTF8Stateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed) - - If *consumed* is *NULL*, behave like :cfunc:`PyUnicode_DecodeUTF8`. If - *consumed* is not *NULL*, trailing incomplete UTF-8 byte sequences will not be - treated as an error. Those bytes will not be decoded and the number of bytes - that have been decoded will be stored in *consumed*. - - -.. cfunction:: PyObject* PyUnicode_EncodeUTF8(const Py_UNICODE *s, Py_ssize_t size, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using UTF-8 and return a - Python string object. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsUTF8String(PyObject *unicode) - - Encode a Unicode object using UTF-8 and return the result as Python string - object. Error handling is "strict". Return *NULL* if an exception was raised - by the codec. - -These are the UTF-32 codec APIs: - -.. % --- UTF-32 Codecs ------------------------------------------------------ */ - - -.. cfunction:: PyObject* PyUnicode_DecodeUTF32(const char *s, Py_ssize_t size, const char *errors, int *byteorder) - - Decode *length* bytes from a UTF-32 encoded buffer string and return the - corresponding Unicode object. *errors* (if non-*NULL*) defines the error - handling. It defaults to "strict". - - If *byteorder* is non-*NULL*, the decoder starts decoding using the given byte - order:: - - *byteorder == -1: little endian - *byteorder == 0: native order - *byteorder == 1: big endian - - and then switches if the first four bytes of the input data are a byte order mark - (BOM) and the specified byte order is native order. This BOM is not copied into - the resulting Unicode string. After completion, *\*byteorder* is set to the - current byte order at the end of input data. - - In a narrow build codepoints outside the BMP will be decoded as surrogate pairs. - - If *byteorder* is *NULL*, the codec starts in native order mode. - - Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_DecodeUTF32Stateful(const char *s, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed) - - If *consumed* is *NULL*, behave like :cfunc:`PyUnicode_DecodeUTF32`. If - *consumed* is not *NULL*, :cfunc:`PyUnicode_DecodeUTF32Stateful` will not treat - trailing incomplete UTF-32 byte sequences (such as a number of bytes not divisible - by four) as an error. Those bytes will not be decoded and the number of bytes - that have been decoded will be stored in *consumed*. - - -.. cfunction:: PyObject* PyUnicode_EncodeUTF32(const Py_UNICODE *s, Py_ssize_t size, const char *errors, int byteorder) - - Return a Python bytes object holding the UTF-32 encoded value of the Unicode - data in *s*. If *byteorder* is not ``0``, output is written according to the - following byte order:: - - byteorder == -1: little endian - byteorder == 0: native byte order (writes a BOM mark) - byteorder == 1: big endian - - If byteorder is ``0``, the output string will always start with the Unicode BOM - mark (U+FEFF). In the other two modes, no BOM mark is prepended. - - If *Py_UNICODE_WIDE* is not defined, surrogate pairs will be output - as a single codepoint. - - Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsUTF32String(PyObject *unicode) - - Return a Python string using the UTF-32 encoding in native byte order. The - string always starts with a BOM mark. Error handling is "strict". Return - *NULL* if an exception was raised by the codec. - - -These are the UTF-16 codec APIs: - -.. % --- UTF-16 Codecs ------------------------------------------------------ */ - - -.. cfunction:: PyObject* PyUnicode_DecodeUTF16(const char *s, Py_ssize_t size, const char *errors, int *byteorder) - - Decode *length* bytes from a UTF-16 encoded buffer string and return the - corresponding Unicode object. *errors* (if non-*NULL*) defines the error - handling. It defaults to "strict". - - If *byteorder* is non-*NULL*, the decoder starts decoding using the given byte - order:: - - *byteorder == -1: little endian - *byteorder == 0: native order - *byteorder == 1: big endian - - and then switches if the first two bytes of the input data are a byte order mark - (BOM) and the specified byte order is native order. This BOM is not copied into - the resulting Unicode string. After completion, *\*byteorder* is set to the - current byte order at the end of input data. - - If *byteorder* is *NULL*, the codec starts in native order mode. - - Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_DecodeUTF16Stateful(const char *s, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed) - - If *consumed* is *NULL*, behave like :cfunc:`PyUnicode_DecodeUTF16`. If - *consumed* is not *NULL*, :cfunc:`PyUnicode_DecodeUTF16Stateful` will not treat - trailing incomplete UTF-16 byte sequences (such as an odd number of bytes or a - split surrogate pair) as an error. Those bytes will not be decoded and the - number of bytes that have been decoded will be stored in *consumed*. - - -.. cfunction:: PyObject* PyUnicode_EncodeUTF16(const Py_UNICODE *s, Py_ssize_t size, const char *errors, int byteorder) - - Return a Python string object holding the UTF-16 encoded value of the Unicode - data in *s*. If *byteorder* is not ``0``, output is written according to the - following byte order:: - - byteorder == -1: little endian - byteorder == 0: native byte order (writes a BOM mark) - byteorder == 1: big endian - - If byteorder is ``0``, the output string will always start with the Unicode BOM - mark (U+FEFF). In the other two modes, no BOM mark is prepended. - - If *Py_UNICODE_WIDE* is defined, a single :ctype:`Py_UNICODE` value may get - represented as a surrogate pair. If it is not defined, each :ctype:`Py_UNICODE` - values is interpreted as an UCS-2 character. - - Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsUTF16String(PyObject *unicode) - - Return a Python string using the UTF-16 encoding in native byte order. The - string always starts with a BOM mark. Error handling is "strict". Return - *NULL* if an exception was raised by the codec. - -These are the "Unicode Escape" codec APIs: - -.. % --- Unicode-Escape Codecs ---------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_DecodeUnicodeEscape(const char *s, Py_ssize_t size, const char *errors) - - Create a Unicode object by decoding *size* bytes of the Unicode-Escape encoded - string *s*. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_EncodeUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using Unicode-Escape and - return a Python string object. Return *NULL* if an exception was raised by the - codec. - - -.. cfunction:: PyObject* PyUnicode_AsUnicodeEscapeString(PyObject *unicode) - - Encode a Unicode object using Unicode-Escape and return the result as Python - string object. Error handling is "strict". Return *NULL* if an exception was - raised by the codec. - -These are the "Raw Unicode Escape" codec APIs: - -.. % --- Raw-Unicode-Escape Codecs ------------------------------------------ - - -.. cfunction:: PyObject* PyUnicode_DecodeRawUnicodeEscape(const char *s, Py_ssize_t size, const char *errors) - - Create a Unicode object by decoding *size* bytes of the Raw-Unicode-Escape - encoded string *s*. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_EncodeRawUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using Raw-Unicode-Escape - and return a Python string object. Return *NULL* if an exception was raised by - the codec. - - -.. cfunction:: PyObject* PyUnicode_AsRawUnicodeEscapeString(PyObject *unicode) - - Encode a Unicode object using Raw-Unicode-Escape and return the result as - Python string object. Error handling is "strict". Return *NULL* if an exception - was raised by the codec. - -These are the Latin-1 codec APIs: Latin-1 corresponds to the first 256 Unicode -ordinals and only these are accepted by the codecs during encoding. - -.. % --- Latin-1 Codecs ----------------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_DecodeLatin1(const char *s, Py_ssize_t size, const char *errors) - - Create a Unicode object by decoding *size* bytes of the Latin-1 encoded string - *s*. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_EncodeLatin1(const Py_UNICODE *s, Py_ssize_t size, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using Latin-1 and return - a Python string object. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsLatin1String(PyObject *unicode) - - Encode a Unicode object using Latin-1 and return the result as Python string - object. Error handling is "strict". Return *NULL* if an exception was raised - by the codec. - -These are the ASCII codec APIs. Only 7-bit ASCII data is accepted. All other -codes generate errors. - -.. % --- ASCII Codecs ------------------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_DecodeASCII(const char *s, Py_ssize_t size, const char *errors) - - Create a Unicode object by decoding *size* bytes of the ASCII encoded string - *s*. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_EncodeASCII(const Py_UNICODE *s, Py_ssize_t size, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using ASCII and return a - Python string object. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsASCIIString(PyObject *unicode) - - Encode a Unicode object using ASCII and return the result as Python string - object. Error handling is "strict". Return *NULL* if an exception was raised - by the codec. - -These are the mapping codec APIs: - -.. % --- Character Map Codecs ----------------------------------------------- - -This codec is special in that it can be used to implement many different codecs -(and this is in fact what was done to obtain most of the standard codecs -included in the :mod:`encodings` package). The codec uses mapping to encode and -decode characters. - -Decoding mappings must map single string characters to single Unicode -characters, integers (which are then interpreted as Unicode ordinals) or None -(meaning "undefined mapping" and causing an error). - -Encoding mappings must map single Unicode characters to single string -characters, integers (which are then interpreted as Latin-1 ordinals) or None -(meaning "undefined mapping" and causing an error). - -The mapping objects provided must only support the __getitem__ mapping -interface. - -If a character lookup fails with a LookupError, the character is copied as-is -meaning that its ordinal value will be interpreted as Unicode or Latin-1 ordinal -resp. Because of this, mappings only need to contain those mappings which map -characters to different code points. - - -.. cfunction:: PyObject* PyUnicode_DecodeCharmap(const char *s, Py_ssize_t size, PyObject *mapping, const char *errors) - - Create a Unicode object by decoding *size* bytes of the encoded string *s* using - the given *mapping* object. Return *NULL* if an exception was raised by the - codec. If *mapping* is *NULL* latin-1 decoding will be done. Else it can be a - dictionary mapping byte or a unicode string, which is treated as a lookup table. - Byte values greater that the length of the string and U+FFFE "characters" are - treated as "undefined mapping". - - -.. cfunction:: PyObject* PyUnicode_EncodeCharmap(const Py_UNICODE *s, Py_ssize_t size, PyObject *mapping, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using the given - *mapping* object and return a Python string object. Return *NULL* if an - exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsCharmapString(PyObject *unicode, PyObject *mapping) - - Encode a Unicode object using the given *mapping* object and return the result - as Python string object. Error handling is "strict". Return *NULL* if an - exception was raised by the codec. - -The following codec API is special in that maps Unicode to Unicode. - - -.. cfunction:: PyObject* PyUnicode_TranslateCharmap(const Py_UNICODE *s, Py_ssize_t size, PyObject *table, const char *errors) - - Translate a :ctype:`Py_UNICODE` buffer of the given length by applying a - character mapping *table* to it and return the resulting Unicode object. Return - *NULL* when an exception was raised by the codec. - - The *mapping* table must map Unicode ordinal integers to Unicode ordinal - integers or None (causing deletion of the character). - - Mapping tables need only provide the :meth:`__getitem__` interface; dictionaries - and sequences work well. Unmapped character ordinals (ones which cause a - :exc:`LookupError`) are left untouched and are copied as-is. - -These are the MBCS codec APIs. They are currently only available on Windows and -use the Win32 MBCS converters to implement the conversions. Note that MBCS (or -DBCS) is a class of encodings, not just one. The target encoding is defined by -the user settings on the machine running the codec. - -.. % --- MBCS codecs for Windows -------------------------------------------- - - -.. cfunction:: PyObject* PyUnicode_DecodeMBCS(const char *s, Py_ssize_t size, const char *errors) - - Create a Unicode object by decoding *size* bytes of the MBCS encoded string *s*. - Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_DecodeMBCSStateful(const char *s, int size, const char *errors, int *consumed) - - If *consumed* is *NULL*, behave like :cfunc:`PyUnicode_DecodeMBCS`. If - *consumed* is not *NULL*, :cfunc:`PyUnicode_DecodeMBCSStateful` will not decode - trailing lead byte and the number of bytes that have been decoded will be stored - in *consumed*. - - -.. cfunction:: PyObject* PyUnicode_EncodeMBCS(const Py_UNICODE *s, Py_ssize_t size, const char *errors) - - Encode the :ctype:`Py_UNICODE` buffer of the given size using MBCS and return a - Python string object. Return *NULL* if an exception was raised by the codec. - - -.. cfunction:: PyObject* PyUnicode_AsMBCSString(PyObject *unicode) - - Encode a Unicode object using MBCS and return the result as Python string - object. Error handling is "strict". Return *NULL* if an exception was raised - by the codec. - -.. % --- Methods & Slots ---------------------------------------------------- - - -.. _unicodemethodsandslots: - -Methods and Slot Functions -^^^^^^^^^^^^^^^^^^^^^^^^^^ - -The following APIs are capable of handling Unicode objects and strings on input -(we refer to them as strings in the descriptions) and return Unicode objects or -integers as appropriate. - -They all return *NULL* or ``-1`` if an exception occurs. - - -.. cfunction:: PyObject* PyUnicode_Concat(PyObject *left, PyObject *right) - - Concat two strings giving a new Unicode string. - - -.. cfunction:: PyObject* PyUnicode_Split(PyObject *s, PyObject *sep, Py_ssize_t maxsplit) - - Split a string giving a list of Unicode strings. If sep is *NULL*, splitting - will be done at all whitespace substrings. Otherwise, splits occur at the given - separator. At most *maxsplit* splits will be done. If negative, no limit is - set. Separators are not included in the resulting list. - - -.. cfunction:: PyObject* PyUnicode_Splitlines(PyObject *s, int keepend) - - Split a Unicode string at line breaks, returning a list of Unicode strings. - CRLF is considered to be one line break. If *keepend* is 0, the Line break - characters are not included in the resulting strings. - - -.. cfunction:: PyObject* PyUnicode_Translate(PyObject *str, PyObject *table, const char *errors) - - Translate a string by applying a character mapping table to it and return the - resulting Unicode object. - - The mapping table must map Unicode ordinal integers to Unicode ordinal integers - or None (causing deletion of the character). - - Mapping tables need only provide the :meth:`__getitem__` interface; dictionaries - and sequences work well. Unmapped character ordinals (ones which cause a - :exc:`LookupError`) are left untouched and are copied as-is. - - *errors* has the usual meaning for codecs. It may be *NULL* which indicates to - use the default error handling. - - -.. cfunction:: PyObject* PyUnicode_Join(PyObject *separator, PyObject *seq) - - Join a sequence of strings using the given separator and return the resulting - Unicode string. - - -.. cfunction:: int PyUnicode_Tailmatch(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction) - - Return 1 if *substr* matches *str*[*start*:*end*] at the given tail end - (*direction* == -1 means to do a prefix match, *direction* == 1 a suffix match), - 0 otherwise. Return ``-1`` if an error occurred. - - -.. cfunction:: Py_ssize_t PyUnicode_Find(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction) - - Return the first position of *substr* in *str*[*start*:*end*] using the given - *direction* (*direction* == 1 means to do a forward search, *direction* == -1 a - backward search). The return value is the index of the first match; a value of - ``-1`` indicates that no match was found, and ``-2`` indicates that an error - occurred and an exception has been set. - - -.. cfunction:: Py_ssize_t PyUnicode_Count(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end) - - Return the number of non-overlapping occurrences of *substr* in - ``str[start:end]``. Return ``-1`` if an error occurred. - - -.. cfunction:: PyObject* PyUnicode_Replace(PyObject *str, PyObject *substr, PyObject *replstr, Py_ssize_t maxcount) - - Replace at most *maxcount* occurrences of *substr* in *str* with *replstr* and - return the resulting Unicode object. *maxcount* == -1 means replace all - occurrences. - - -.. cfunction:: int PyUnicode_Compare(PyObject *left, PyObject *right) - - Compare two strings and return -1, 0, 1 for less than, equal, and greater than, - respectively. - - -.. cfunction:: int PyUnicode_RichCompare(PyObject *left, PyObject *right, int op) - - Rich compare two unicode strings and return one of the following: - - * ``NULL`` in case an exception was raised - * :const:`Py_True` or :const:`Py_False` for successful comparisons - * :const:`Py_NotImplemented` in case the type combination is unknown - - Note that :const:`Py_EQ` and :const:`Py_NE` comparisons can cause a - :exc:`UnicodeWarning` in case the conversion of the arguments to Unicode fails - with a :exc:`UnicodeDecodeError`. - - Possible values for *op* are :const:`Py_GT`, :const:`Py_GE`, :const:`Py_EQ`, - :const:`Py_NE`, :const:`Py_LT`, and :const:`Py_LE`. - - -.. cfunction:: PyObject* PyUnicode_Format(PyObject *format, PyObject *args) - - Return a new string object from *format* and *args*; this is analogous to - ``format % args``. The *args* argument must be a tuple. - - -.. cfunction:: int PyUnicode_Contains(PyObject *container, PyObject *element) - - Check whether *element* is contained in *container* and return true or false - accordingly. - - *element* has to coerce to a one element Unicode string. ``-1`` is returned if - there was an error. - - -.. cfunction:: void PyUnicode_InternInPlace(PyObject **string) - - Intern the argument *\*string* in place. The argument must be the address of a - pointer variable pointing to a Python unicode string object. If there is an - existing interned string that is the same as *\*string*, it sets *\*string* to - it (decrementing the reference count of the old string object and incrementing - the reference count of the interned string object), otherwise it leaves - *\*string* alone and interns it (incrementing its reference count). - (Clarification: even though there is a lot of talk about reference counts, think - of this function as reference-count-neutral; you own the object after the call - if and only if you owned it before the call.) - - -.. cfunction:: PyObject* PyUnicode_InternFromString(const char *v) - - A combination of :cfunc:`PyUnicode_FromString` and - :cfunc:`PyUnicode_InternInPlace`, returning either a new unicode string object - that has been interned, or a new ("owned") reference to an earlier interned - string object with the same value. - - -.. _bufferobjects: - -Buffer Objects --------------- - -.. sectionauthor:: Greg Stein <gstein@lyra.org> - - -.. index:: - object: buffer - single: buffer interface - -Python objects implemented in C can export a group of functions called the -"buffer interface." These functions can be used by an object to expose its data -in a raw, byte-oriented format. Clients of the object can use the buffer -interface to access the object data directly, without needing to copy it first. - -Two examples of objects that support the buffer interface are strings and -arrays. The string object exposes the character contents in the buffer -interface's byte-oriented form. An array can also expose its contents, but it -should be noted that array elements may be multi-byte values. - -An example user of the buffer interface is the file object's :meth:`write` -method. Any object that can export a series of bytes through the buffer -interface can be written to a file. There are a number of format codes to -:cfunc:`PyArg_ParseTuple` that operate against an object's buffer interface, -returning data from the target object. - -.. index:: single: PyBufferProcs - -More information on the buffer interface is provided in the section -:ref:`buffer-structs`, under the description for :ctype:`PyBufferProcs`. - -A "buffer object" is defined in the :file:`bufferobject.h` header (included by -:file:`Python.h`). These objects look very similar to string objects at the -Python programming level: they support slicing, indexing, concatenation, and -some other standard string operations. However, their data can come from one of -two sources: from a block of memory, or from another object which exports the -buffer interface. - -Buffer objects are useful as a way to expose the data from another object's -buffer interface to the Python programmer. They can also be used as a zero-copy -slicing mechanism. Using their ability to reference a block of memory, it is -possible to expose any data to the Python programmer quite easily. The memory -could be a large, constant array in a C extension, it could be a raw block of -memory for manipulation before passing to an operating system library, or it -could be used to pass around structured data in its native, in-memory format. - - -.. ctype:: PyBufferObject - - This subtype of :ctype:`PyObject` represents a buffer object. - - -.. cvar:: PyTypeObject PyBuffer_Type - - .. index:: single: BufferType (in module types) - - The instance of :ctype:`PyTypeObject` which represents the Python buffer type; - it is the same object as ``buffer`` and ``types.BufferType`` in the Python - layer. . - - -.. cvar:: int Py_END_OF_BUFFER - - This constant may be passed as the *size* parameter to - :cfunc:`PyBuffer_FromObject` or :cfunc:`PyBuffer_FromReadWriteObject`. It - indicates that the new :ctype:`PyBufferObject` should refer to *base* object - from the specified *offset* to the end of its exported buffer. Using this - enables the caller to avoid querying the *base* object for its length. - - -.. cfunction:: int PyBuffer_Check(PyObject *p) - - Return true if the argument has type :cdata:`PyBuffer_Type`. - - -.. cfunction:: PyObject* PyBuffer_FromObject(PyObject *base, Py_ssize_t offset, Py_ssize_t size) - - Return a new read-only buffer object. This raises :exc:`TypeError` if *base* - doesn't support the read-only buffer protocol or doesn't provide exactly one - buffer segment, or it raises :exc:`ValueError` if *offset* is less than zero. - The buffer will hold a reference to the *base* object, and the buffer's contents - will refer to the *base* object's buffer interface, starting as position - *offset* and extending for *size* bytes. If *size* is :const:`Py_END_OF_BUFFER`, - then the new buffer's contents extend to the length of the *base* object's - exported buffer data. - +.. toctree:: -.. cfunction:: PyObject* PyBuffer_FromReadWriteObject(PyObject *base, Py_ssize_t offset, Py_ssize_t size) - - Return a new writable buffer object. Parameters and exceptions are similar to - those for :cfunc:`PyBuffer_FromObject`. If the *base* object does not export - the writable buffer protocol, then :exc:`TypeError` is raised. - - -.. cfunction:: PyObject* PyBuffer_FromMemory(void *ptr, Py_ssize_t size) - - Return a new read-only buffer object that reads from a specified location in - memory, with a specified size. The caller is responsible for ensuring that the - memory buffer, passed in as *ptr*, is not deallocated while the returned buffer - object exists. Raises :exc:`ValueError` if *size* is less than zero. Note that - :const:`Py_END_OF_BUFFER` may *not* be passed for the *size* parameter; - :exc:`ValueError` will be raised in that case. - - -.. cfunction:: PyObject* PyBuffer_FromReadWriteMemory(void *ptr, Py_ssize_t size) - - Similar to :cfunc:`PyBuffer_FromMemory`, but the returned buffer is writable. - - -.. cfunction:: PyObject* PyBuffer_New(Py_ssize_t size) - - Return a new writable buffer object that maintains its own memory buffer of - *size* bytes. :exc:`ValueError` is returned if *size* is not zero or positive. - Note that the memory buffer (as returned by :cfunc:`PyObject_AsWriteBuffer`) is - not specifically aligned. - - -.. _tupleobjects: - -Tuple Objects -------------- - -.. index:: object: tuple - - -.. ctype:: PyTupleObject - - This subtype of :ctype:`PyObject` represents a Python tuple object. - - -.. cvar:: PyTypeObject PyTuple_Type - - .. index:: single: TupleType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python tuple type; it is - the same object as ``tuple`` and ``types.TupleType`` in the Python layer.. - - -.. cfunction:: int PyTuple_Check(PyObject *p) - - Return true if *p* is a tuple object or an instance of a subtype of the tuple - type. - - -.. cfunction:: int PyTuple_CheckExact(PyObject *p) - - Return true if *p* is a tuple object, but not an instance of a subtype of the - tuple type. - - -.. cfunction:: PyObject* PyTuple_New(Py_ssize_t len) - - Return a new tuple object of size *len*, or *NULL* on failure. - - -.. cfunction:: PyObject* PyTuple_Pack(Py_ssize_t n, ...) - - Return a new tuple object of size *n*, or *NULL* on failure. The tuple values - are initialized to the subsequent *n* C arguments pointing to Python objects. - ``PyTuple_Pack(2, a, b)`` is equivalent to ``Py_BuildValue("(OO)", a, b)``. - - -.. cfunction:: Py_ssize_t PyTuple_Size(PyObject *p) - - Take a pointer to a tuple object, and return the size of that tuple. - - -.. cfunction:: Py_ssize_t PyTuple_GET_SIZE(PyObject *p) - - Return the size of the tuple *p*, which must be non-*NULL* and point to a tuple; - no error checking is performed. - - -.. cfunction:: PyObject* PyTuple_GetItem(PyObject *p, Py_ssize_t pos) - - Return the object at position *pos* in the tuple pointed to by *p*. If *pos* is - out of bounds, return *NULL* and sets an :exc:`IndexError` exception. - - -.. cfunction:: PyObject* PyTuple_GET_ITEM(PyObject *p, Py_ssize_t pos) - - Like :cfunc:`PyTuple_GetItem`, but does no checking of its arguments. - - -.. cfunction:: PyObject* PyTuple_GetSlice(PyObject *p, Py_ssize_t low, Py_ssize_t high) - - Take a slice of the tuple pointed to by *p* from *low* to *high* and return it - as a new tuple. - - -.. cfunction:: int PyTuple_SetItem(PyObject *p, Py_ssize_t pos, PyObject *o) - - Insert a reference to object *o* at position *pos* of the tuple pointed to by - *p*. Return ``0`` on success. - - .. note:: - - This function "steals" a reference to *o*. - - -.. cfunction:: void PyTuple_SET_ITEM(PyObject *p, Py_ssize_t pos, PyObject *o) - - Like :cfunc:`PyTuple_SetItem`, but does no error checking, and should *only* be - used to fill in brand new tuples. - - .. note:: - - This function "steals" a reference to *o*. - - -.. cfunction:: int _PyTuple_Resize(PyObject **p, Py_ssize_t newsize) - - Can be used to resize a tuple. *newsize* will be the new length of the tuple. - Because tuples are *supposed* to be immutable, this should only be used if there - is only one reference to the object. Do *not* use this if the tuple may already - be known to some other part of the code. The tuple will always grow or shrink - at the end. Think of this as destroying the old tuple and creating a new one, - only more efficiently. Returns ``0`` on success. Client code should never - assume that the resulting value of ``*p`` will be the same as before calling - this function. If the object referenced by ``*p`` is replaced, the original - ``*p`` is destroyed. On failure, returns ``-1`` and sets ``*p`` to *NULL*, and - raises :exc:`MemoryError` or :exc:`SystemError`. - - -.. _listobjects: - -List Objects ------------- - -.. index:: object: list - - -.. ctype:: PyListObject - - This subtype of :ctype:`PyObject` represents a Python list object. - - -.. cvar:: PyTypeObject PyList_Type - - .. index:: single: ListType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python list type. This is - the same object as ``list`` and ``types.ListType`` in the Python layer. - - -.. cfunction:: int PyList_Check(PyObject *p) - - Return true if *p* is a list object or an instance of a subtype of the list - type. - - -.. cfunction:: int PyList_CheckExact(PyObject *p) - - Return true if *p* is a list object, but not an instance of a subtype of the - list type. - - -.. cfunction:: PyObject* PyList_New(Py_ssize_t len) - - Return a new list of length *len* on success, or *NULL* on failure. - - .. note:: - - If *length* is greater than zero, the returned list object's items are set to - ``NULL``. Thus you cannot use abstract API functions such as - :cfunc:`PySequence_SetItem` or expose the object to Python code before setting - all items to a real object with :cfunc:`PyList_SetItem`. - - -.. cfunction:: Py_ssize_t PyList_Size(PyObject *list) - - .. index:: builtin: len - - Return the length of the list object in *list*; this is equivalent to - ``len(list)`` on a list object. - - -.. cfunction:: Py_ssize_t PyList_GET_SIZE(PyObject *list) - - Macro form of :cfunc:`PyList_Size` without error checking. - - -.. cfunction:: PyObject* PyList_GetItem(PyObject *list, Py_ssize_t index) - - Return the object at position *pos* in the list pointed to by *p*. The position - must be positive, indexing from the end of the list is not supported. If *pos* - is out of bounds, return *NULL* and set an :exc:`IndexError` exception. - - -.. cfunction:: PyObject* PyList_GET_ITEM(PyObject *list, Py_ssize_t i) - - Macro form of :cfunc:`PyList_GetItem` without error checking. - - -.. cfunction:: int PyList_SetItem(PyObject *list, Py_ssize_t index, PyObject *item) - - Set the item at index *index* in list to *item*. Return ``0`` on success or - ``-1`` on failure. - - .. note:: - - This function "steals" a reference to *item* and discards a reference to an item - already in the list at the affected position. - - -.. cfunction:: void PyList_SET_ITEM(PyObject *list, Py_ssize_t i, PyObject *o) - - Macro form of :cfunc:`PyList_SetItem` without error checking. This is normally - only used to fill in new lists where there is no previous content. - - .. note:: - - This function "steals" a reference to *item*, and, unlike - :cfunc:`PyList_SetItem`, does *not* discard a reference to any item that it - being replaced; any reference in *list* at position *i* will be leaked. - - -.. cfunction:: int PyList_Insert(PyObject *list, Py_ssize_t index, PyObject *item) - - Insert the item *item* into list *list* in front of index *index*. Return ``0`` - if successful; return ``-1`` and set an exception if unsuccessful. Analogous to - ``list.insert(index, item)``. - - -.. cfunction:: int PyList_Append(PyObject *list, PyObject *item) - - Append the object *item* at the end of list *list*. Return ``0`` if successful; - return ``-1`` and set an exception if unsuccessful. Analogous to - ``list.append(item)``. - - -.. cfunction:: PyObject* PyList_GetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high) - - Return a list of the objects in *list* containing the objects *between* *low* - and *high*. Return *NULL* and set an exception if unsuccessful. Analogous to - ``list[low:high]``. - - -.. cfunction:: int PyList_SetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high, PyObject *itemlist) - - Set the slice of *list* between *low* and *high* to the contents of *itemlist*. - Analogous to ``list[low:high] = itemlist``. The *itemlist* may be *NULL*, - indicating the assignment of an empty list (slice deletion). Return ``0`` on - success, ``-1`` on failure. - - -.. cfunction:: int PyList_Sort(PyObject *list) - - Sort the items of *list* in place. Return ``0`` on success, ``-1`` on failure. - This is equivalent to ``list.sort()``. - - -.. cfunction:: int PyList_Reverse(PyObject *list) - - Reverse the items of *list* in place. Return ``0`` on success, ``-1`` on - failure. This is the equivalent of ``list.reverse()``. - - -.. cfunction:: PyObject* PyList_AsTuple(PyObject *list) - - .. index:: builtin: tuple - - Return a new tuple object containing the contents of *list*; equivalent to - ``tuple(list)``. + string.rst + unicode.rst + buffer.rst + tuple.rst + list.rst .. _mapobjects: @@ -2105,211 +79,9 @@ Mapping Objects .. index:: object: mapping +.. toctree:: -.. _dictobjects: - -Dictionary Objects ------------------- - -.. index:: object: dictionary - - -.. ctype:: PyDictObject - - This subtype of :ctype:`PyObject` represents a Python dictionary object. - - -.. cvar:: PyTypeObject PyDict_Type - - .. index:: - single: DictType (in module types) - single: DictionaryType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python dictionary type. - This is exposed to Python programs as ``dict`` and ``types.DictType``. - - -.. cfunction:: int PyDict_Check(PyObject *p) - - Return true if *p* is a dict object or an instance of a subtype of the dict - type. - - -.. cfunction:: int PyDict_CheckExact(PyObject *p) - - Return true if *p* is a dict object, but not an instance of a subtype of the - dict type. - - -.. cfunction:: PyObject* PyDict_New() - - Return a new empty dictionary, or *NULL* on failure. - - -.. cfunction:: PyObject* PyDictProxy_New(PyObject *dict) - - Return a proxy object for a mapping which enforces read-only behavior. This is - normally used to create a proxy to prevent modification of the dictionary for - non-dynamic class types. - - -.. cfunction:: void PyDict_Clear(PyObject *p) - - Empty an existing dictionary of all key-value pairs. - - -.. cfunction:: int PyDict_Contains(PyObject *p, PyObject *key) - - Determine if dictionary *p* contains *key*. If an item in *p* is matches *key*, - return ``1``, otherwise return ``0``. On error, return ``-1``. This is - equivalent to the Python expression ``key in p``. - - -.. cfunction:: PyObject* PyDict_Copy(PyObject *p) - - Return a new dictionary that contains the same key-value pairs as *p*. - - -.. cfunction:: int PyDict_SetItem(PyObject *p, PyObject *key, PyObject *val) - - Insert *value* into the dictionary *p* with a key of *key*. *key* must be - :term:`hashable`; if it isn't, :exc:`TypeError` will be raised. Return ``0`` - on success or ``-1`` on failure. - - -.. cfunction:: int PyDict_SetItemString(PyObject *p, const char *key, PyObject *val) - - .. index:: single: PyString_FromString() - - Insert *value* into the dictionary *p* using *key* as a key. *key* should be a - :ctype:`char\*`. The key object is created using ``PyString_FromString(key)``. - Return ``0`` on success or ``-1`` on failure. - - -.. cfunction:: int PyDict_DelItem(PyObject *p, PyObject *key) - - Remove the entry in dictionary *p* with key *key*. *key* must be hashable; if it - isn't, :exc:`TypeError` is raised. Return ``0`` on success or ``-1`` on - failure. - - -.. cfunction:: int PyDict_DelItemString(PyObject *p, char *key) - - Remove the entry in dictionary *p* which has a key specified by the string - *key*. Return ``0`` on success or ``-1`` on failure. - - -.. cfunction:: PyObject* PyDict_GetItem(PyObject *p, PyObject *key) - - Return the object from dictionary *p* which has a key *key*. Return *NULL* if - the key *key* is not present, but *without* setting an exception. - - -.. cfunction:: PyObject* PyDict_GetItemString(PyObject *p, const char *key) - - This is the same as :cfunc:`PyDict_GetItem`, but *key* is specified as a - :ctype:`char\*`, rather than a :ctype:`PyObject\*`. - - -.. cfunction:: PyObject* PyDict_Items(PyObject *p) - - Return a :ctype:`PyListObject` containing all the items from the dictionary, as - in the dictionary method :meth:`dict.items`. - - -.. cfunction:: PyObject* PyDict_Keys(PyObject *p) - - Return a :ctype:`PyListObject` containing all the keys from the dictionary, as - in the dictionary method :meth:`dict.keys`. - - -.. cfunction:: PyObject* PyDict_Values(PyObject *p) - - Return a :ctype:`PyListObject` containing all the values from the dictionary - *p*, as in the dictionary method :meth:`dict.values`. - - -.. cfunction:: Py_ssize_t PyDict_Size(PyObject *p) - - .. index:: builtin: len - - Return the number of items in the dictionary. This is equivalent to ``len(p)`` - on a dictionary. - - -.. cfunction:: int PyDict_Next(PyObject *p, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue) - - Iterate over all key-value pairs in the dictionary *p*. The :ctype:`int` - referred to by *ppos* must be initialized to ``0`` prior to the first call to - this function to start the iteration; the function returns true for each pair in - the dictionary, and false once all pairs have been reported. The parameters - *pkey* and *pvalue* should either point to :ctype:`PyObject\*` variables that - will be filled in with each key and value, respectively, or may be *NULL*. Any - references returned through them are borrowed. *ppos* should not be altered - during iteration. Its value represents offsets within the internal dictionary - structure, and since the structure is sparse, the offsets are not consecutive. - - For example:: - - PyObject *key, *value; - Py_ssize_t pos = 0; - - while (PyDict_Next(self->dict, &pos, &key, &value)) { - /* do something interesting with the values... */ - ... - } - - The dictionary *p* should not be mutated during iteration. It is safe (since - Python 2.1) to modify the values of the keys as you iterate over the dictionary, - but only so long as the set of keys does not change. For example:: - - PyObject *key, *value; - Py_ssize_t pos = 0; - - while (PyDict_Next(self->dict, &pos, &key, &value)) { - long i = PyLong_AsLong(value); - if (i == -1 && PyErr_Occurred()) { - return -1; - } - PyObject *o = PyLong_FromLong(i + 1); - if (o == NULL) - return -1; - if (PyDict_SetItem(self->dict, key, o) < 0) { - Py_DECREF(o); - return -1; - } - Py_DECREF(o); - } - - -.. cfunction:: int PyDict_Merge(PyObject *a, PyObject *b, int override) - - Iterate over mapping object *b* adding key-value pairs to dictionary *a*. *b* - may be a dictionary, or any object supporting :func:`PyMapping_Keys` and - :func:`PyObject_GetItem`. If *override* is true, existing pairs in *a* will be - replaced if a matching key is found in *b*, otherwise pairs will only be added - if there is not a matching key in *a*. Return ``0`` on success or ``-1`` if an - exception was raised. - - -.. cfunction:: int PyDict_Update(PyObject *a, PyObject *b) - - This is the same as ``PyDict_Merge(a, b, 1)`` in C, or ``a.update(b)`` in - Python. Return ``0`` on success or ``-1`` if an exception was raised. - - -.. cfunction:: int PyDict_MergeFromSeq2(PyObject *a, PyObject *seq2, int override) - - Update or merge into dictionary *a*, from the key-value pairs in *seq2*. *seq2* - must be an iterable object producing iterable objects of length 2, viewed as - key-value pairs. In case of duplicate keys, the last wins if *override* is - true, else the first wins. Return ``0`` on success or ``-1`` if an exception was - raised. Equivalent Python (except for the return value):: - - def PyDict_MergeFromSeq2(a, seq2, override): - for key, value in seq2: - if override or key not in a: - a[key] = value + dict.rst .. _otherobjects: @@ -2317,1089 +89,18 @@ Dictionary Objects Other Objects ============= -.. _fileobjects: - -File Objects ------------- - -.. index:: object: file - -Python's built-in file objects are implemented entirely on the :ctype:`FILE\*` -support from the C standard library. This is an implementation detail and may -change in future releases of Python. - - -.. ctype:: PyFileObject - - This subtype of :ctype:`PyObject` represents a Python file object. - - -.. cvar:: PyTypeObject PyFile_Type - - .. index:: single: FileType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python file type. This is - exposed to Python programs as ``file`` and ``types.FileType``. - - -.. cfunction:: int PyFile_Check(PyObject *p) - - Return true if its argument is a :ctype:`PyFileObject` or a subtype of - :ctype:`PyFileObject`. - - -.. cfunction:: int PyFile_CheckExact(PyObject *p) - - Return true if its argument is a :ctype:`PyFileObject`, but not a subtype of - :ctype:`PyFileObject`. - - -.. cfunction:: PyFile_FromFd(int fd, char *name, char *mode, int buffering, char *encoding, char *newline, int closefd) - - Create a new :ctype:`PyFileObject` from the file descriptor of an already - opened file *fd*. The arguments *name*, *encoding* and *newline* can be - *NULL* to use the defaults; *buffering* can be *-1* to use the default. - Return *NULL* on failure. - - .. warning:: - - Take care when you are mixing streams and descriptors! For more - information, see `the GNU C Library docs - <http://www.gnu.org/software/libc/manual/html_node/Stream_002fDescriptor-Precautions.html#Stream_002fDescriptor-Precautions>`_. - - -.. cfunction:: int PyObject_AsFileDescriptor(PyObject *p) - - Return the file descriptor associated with *p* as an :ctype:`int`. If the - object is an integer, its value is returned. If not, the - object's :meth:`fileno` method is called if it exists; the method must return - an integer, which is returned as the file descriptor value. Sets an - exception and returns ``-1`` on failure. - - -.. cfunction:: PyObject* PyFile_GetLine(PyObject *p, int n) - - .. index:: single: EOFError (built-in exception) - - Equivalent to ``p.readline([n])``, this function reads one line from the - object *p*. *p* may be a file object or any object with a :meth:`readline` - method. If *n* is ``0``, exactly one line is read, regardless of the length of - the line. If *n* is greater than ``0``, no more than *n* bytes will be read - from the file; a partial line can be returned. In both cases, an empty string - is returned if the end of the file is reached immediately. If *n* is less than - ``0``, however, one line is read regardless of length, but :exc:`EOFError` is - raised if the end of the file is reached immediately. - - -.. cfunction:: PyObject* PyFile_Name(PyObject *p) - - Return the name of the file specified by *p* as a string object. - - -.. cfunction:: void PyFile_SetBufSize(PyFileObject *p, int n) - - .. index:: single: setvbuf() - - Available on systems with :cfunc:`setvbuf` only. This should only be called - immediately after file object creation. - - -.. cfunction:: int PyFile_SetEncoding(PyFileObject *p, const char *enc) - - Set the file's encoding for Unicode output to *enc*. Return 1 on success and 0 - on failure. - - -.. cfunction:: int PyFile_SoftSpace(PyObject *p, int newflag) - - .. index:: single: softspace (file attribute) - - This function exists for internal use by the interpreter. Set the - :attr:`softspace` attribute of *p* to *newflag* and return the previous value. - *p* does not have to be a file object for this function to work properly; any - object is supported (thought its only interesting if the :attr:`softspace` - attribute can be set). This function clears any errors, and will return ``0`` - as the previous value if the attribute either does not exist or if there were - errors in retrieving it. There is no way to detect errors from this function, - but doing so should not be needed. - - -.. cfunction:: int PyFile_WriteObject(PyObject *obj, PyObject *p, int flags) - - .. index:: single: Py_PRINT_RAW - - Write object *obj* to file object *p*. The only supported flag for *flags* is - :const:`Py_PRINT_RAW`; if given, the :func:`str` of the object is written - instead of the :func:`repr`. Return ``0`` on success or ``-1`` on failure; the - appropriate exception will be set. - - -.. cfunction:: int PyFile_WriteString(const char *s, PyObject *p) - - Write string *s* to file object *p*. Return ``0`` on success or ``-1`` on - failure; the appropriate exception will be set. - - -.. _function-objects: - -Function Objects ----------------- - -.. index:: object: function - -There are a few functions specific to Python functions. - - -.. ctype:: PyFunctionObject - - The C structure used for functions. - - -.. cvar:: PyTypeObject PyFunction_Type - - .. index:: single: MethodType (in module types) - - This is an instance of :ctype:`PyTypeObject` and represents the Python function - type. It is exposed to Python programmers as ``types.FunctionType``. - - -.. cfunction:: int PyFunction_Check(PyObject *o) - - Return true if *o* is a function object (has type :cdata:`PyFunction_Type`). - The parameter must not be *NULL*. - - -.. cfunction:: PyObject* PyFunction_New(PyObject *code, PyObject *globals) - - Return a new function object associated with the code object *code*. *globals* - must be a dictionary with the global variables accessible to the function. - - The function's docstring, name and *__module__* are retrieved from the code - object, the argument defaults and closure are set to *NULL*. - - -.. cfunction:: PyObject* PyFunction_GetCode(PyObject *op) - - Return the code object associated with the function object *op*. - - -.. cfunction:: PyObject* PyFunction_GetGlobals(PyObject *op) - - Return the globals dictionary associated with the function object *op*. - - -.. cfunction:: PyObject* PyFunction_GetModule(PyObject *op) - - Return the *__module__* attribute of the function object *op*. This is normally - a string containing the module name, but can be set to any other object by - Python code. - - -.. cfunction:: PyObject* PyFunction_GetDefaults(PyObject *op) - - Return the argument default values of the function object *op*. This can be a - tuple of arguments or *NULL*. - - -.. cfunction:: int PyFunction_SetDefaults(PyObject *op, PyObject *defaults) - - Set the argument default values for the function object *op*. *defaults* must be - *Py_None* or a tuple. - - Raises :exc:`SystemError` and returns ``-1`` on failure. - - -.. cfunction:: PyObject* PyFunction_GetClosure(PyObject *op) - - Return the closure associated with the function object *op*. This can be *NULL* - or a tuple of cell objects. - - -.. cfunction:: int PyFunction_SetClosure(PyObject *op, PyObject *closure) - - Set the closure associated with the function object *op*. *closure* must be - *Py_None* or a tuple of cell objects. - - Raises :exc:`SystemError` and returns ``-1`` on failure. - - -.. _instancemethod-objects: - -Instance Method Objects ------------------------ - -.. index:: object: instancemethod - -An instance method is a wrapper for a :cdata:`PyCFunction` and the new way -to bind a :cdata:`PyCFunction` to a class object. It replaces the former call -``PyMethod_New(func, NULL, class)``. - - -.. cvar:: PyTypeObject PyInstanceMethod_Type - - This instance of :ctype:`PyTypeObject` represents the Python instance - method type. It is not exposed to Python programs. - - -.. cfunction:: int PyInstanceMethod_Check(PyObject *o) - - Return true if *o* is an instance method object (has type - :cdata:`PyInstanceMethod_Type`). The parameter must not be *NULL*. - - -.. cfunction:: PyObject* PyInstanceMethod_New(PyObject *func) - - Return a new instance method object, with *func* being any callable object - *func* is is the function that will be called when the instance method is - called. - - -.. cfunction:: PyObject* PyInstanceMethod_Function(PyObject *im) - - Return the function object associated with the instance method *im*. - - -.. cfunction:: PyObject* PyInstanceMethod_GET_FUNCTION(PyObject *im) - - Macro version of :cfunc:`PyInstanceMethod_Function` which avoids error checking. - - -.. _method-objects: - -Method Objects --------------- - -.. index:: object: method - -Methods are bound function objects. Methods are always bound to an instance of -an user-defined class. Unbound methods (methods bound to a class object) are -no longer available. - - -.. cvar:: PyTypeObject PyMethod_Type - - .. index:: single: MethodType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python method type. This - is exposed to Python programs as ``types.MethodType``. - - -.. cfunction:: int PyMethod_Check(PyObject *o) - - Return true if *o* is a method object (has type :cdata:`PyMethod_Type`). The - parameter must not be *NULL*. - - -.. cfunction:: PyObject* PyMethod_New(PyObject *func, PyObject *self) - - Return a new method object, with *func* being any callable object and *self* - the instance the method should be bound. *func* is is the function that will - be called when the method is called. *self* must not be *NULL*. - - -.. cfunction:: PyObject* PyMethod_Function(PyObject *meth) - - Return the function object associated with the method *meth*. - - -.. cfunction:: PyObject* PyMethod_GET_FUNCTION(PyObject *meth) - - Macro version of :cfunc:`PyMethod_Function` which avoids error checking. - - -.. cfunction:: PyObject* PyMethod_Self(PyObject *meth) - - Return the instance associated with the method *meth*. - - -.. cfunction:: PyObject* PyMethod_GET_SELF(PyObject *meth) - - Macro version of :cfunc:`PyMethod_Self` which avoids error checking. - - -.. _moduleobjects: - -Module Objects --------------- - -.. index:: object: module - -There are only a few functions special to module objects. - - -.. cvar:: PyTypeObject PyModule_Type - - .. index:: single: ModuleType (in module types) - - This instance of :ctype:`PyTypeObject` represents the Python module type. This - is exposed to Python programs as ``types.ModuleType``. - - -.. cfunction:: int PyModule_Check(PyObject *p) - - Return true if *p* is a module object, or a subtype of a module object. - - -.. cfunction:: int PyModule_CheckExact(PyObject *p) - - Return true if *p* is a module object, but not a subtype of - :cdata:`PyModule_Type`. - - -.. cfunction:: PyObject* PyModule_New(const char *name) - - .. index:: - single: __name__ (module attribute) - single: __doc__ (module attribute) - single: __file__ (module attribute) - - Return a new module object with the :attr:`__name__` attribute set to *name*. - Only the module's :attr:`__doc__` and :attr:`__name__` attributes are filled in; - the caller is responsible for providing a :attr:`__file__` attribute. - - -.. cfunction:: PyObject* PyModule_GetDict(PyObject *module) - - .. index:: single: __dict__ (module attribute) - - Return the dictionary object that implements *module*'s namespace; this object - is the same as the :attr:`__dict__` attribute of the module object. This - function never fails. It is recommended extensions use other - :cfunc:`PyModule_\*` and :cfunc:`PyObject_\*` functions rather than directly - manipulate a module's :attr:`__dict__`. - - -.. cfunction:: char* PyModule_GetName(PyObject *module) - - .. index:: - single: __name__ (module attribute) - single: SystemError (built-in exception) - - Return *module*'s :attr:`__name__` value. If the module does not provide one, - or if it is not a string, :exc:`SystemError` is raised and *NULL* is returned. - - -.. cfunction:: char* PyModule_GetFilename(PyObject *module) - - .. index:: - single: __file__ (module attribute) - single: SystemError (built-in exception) - - Return the name of the file from which *module* was loaded using *module*'s - :attr:`__file__` attribute. If this is not defined, or if it is not a string, - raise :exc:`SystemError` and return *NULL*. - - -.. cfunction:: int PyModule_AddObject(PyObject *module, const char *name, PyObject *value) - - Add an object to *module* as *name*. This is a convenience function which can - be used from the module's initialization function. This steals a reference to - *value*. Return ``-1`` on error, ``0`` on success. - - -.. cfunction:: int PyModule_AddIntConstant(PyObject *module, const char *name, long value) - - Add an integer constant to *module* as *name*. This convenience function can be - used from the module's initialization function. Return ``-1`` on error, ``0`` on - success. - - -.. cfunction:: int PyModule_AddStringConstant(PyObject *module, const char *name, const char *value) - - Add a string constant to *module* as *name*. This convenience function can be - used from the module's initialization function. The string *value* must be - null-terminated. Return ``-1`` on error, ``0`` on success. - - -.. _iterator-objects: - -Iterator Objects ----------------- - -Python provides two general-purpose iterator objects. The first, a sequence -iterator, works with an arbitrary sequence supporting the :meth:`__getitem__` -method. The second works with a callable object and a sentinel value, calling -the callable for each item in the sequence, and ending the iteration when the -sentinel value is returned. - - -.. cvar:: PyTypeObject PySeqIter_Type - - Type object for iterator objects returned by :cfunc:`PySeqIter_New` and the - one-argument form of the :func:`iter` built-in function for built-in sequence - types. - - -.. cfunction:: int PySeqIter_Check(op) - - Return true if the type of *op* is :cdata:`PySeqIter_Type`. - - -.. cfunction:: PyObject* PySeqIter_New(PyObject *seq) - - Return an iterator that works with a general sequence object, *seq*. The - iteration ends when the sequence raises :exc:`IndexError` for the subscripting - operation. - - -.. cvar:: PyTypeObject PyCallIter_Type - - Type object for iterator objects returned by :cfunc:`PyCallIter_New` and the - two-argument form of the :func:`iter` built-in function. - - -.. cfunction:: int PyCallIter_Check(op) - - Return true if the type of *op* is :cdata:`PyCallIter_Type`. - - -.. cfunction:: PyObject* PyCallIter_New(PyObject *callable, PyObject *sentinel) - - Return a new iterator. The first parameter, *callable*, can be any Python - callable object that can be called with no parameters; each call to it should - return the next item in the iteration. When *callable* returns a value equal to - *sentinel*, the iteration will be terminated. - - -.. _descriptor-objects: - -Descriptor Objects ------------------- - -"Descriptors" are objects that describe some attribute of an object. They are -found in the dictionary of type objects. - -.. XXX document these! - -.. cvar:: PyTypeObject PyProperty_Type - - The type object for the built-in descriptor types. - - -.. cfunction:: PyObject* PyDescr_NewGetSet(PyTypeObject *type, struct PyGetSetDef *getset) - - -.. cfunction:: PyObject* PyDescr_NewMember(PyTypeObject *type, struct PyMemberDef *meth) - - -.. cfunction:: PyObject* PyDescr_NewMethod(PyTypeObject *type, struct PyMethodDef *meth) - - -.. cfunction:: PyObject* PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *wrapper, void *wrapped) - - -.. cfunction:: PyObject* PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method) - - -.. cfunction:: int PyDescr_IsData(PyObject *descr) - - Return true if the descriptor objects *descr* describes a data attribute, or - false if it describes a method. *descr* must be a descriptor object; there is - no error checking. - - -.. cfunction:: PyObject* PyWrapper_New(PyObject *, PyObject *) - - -.. _slice-objects: - -Slice Objects -------------- - - -.. cvar:: PyTypeObject PySlice_Type - - .. index:: single: SliceType (in module types) - - The type object for slice objects. This is the same as ``slice`` and - ``types.SliceType``. - - -.. cfunction:: int PySlice_Check(PyObject *ob) - - Return true if *ob* is a slice object; *ob* must not be *NULL*. - - -.. cfunction:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step) - - Return a new slice object with the given values. The *start*, *stop*, and - *step* parameters are used as the values of the slice object attributes of the - same names. Any of the values may be *NULL*, in which case the ``None`` will be - used for the corresponding attribute. Return *NULL* if the new object could not - be allocated. - - -.. cfunction:: int PySlice_GetIndices(PySliceObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step) - - Retrieve the start, stop and step indices from the slice object *slice*, - assuming a sequence of length *length*. Treats indices greater than *length* as - errors. - - Returns 0 on success and -1 on error with no exception set (unless one of the - indices was not :const:`None` and failed to be converted to an integer, in which - case -1 is returned with an exception set). - - You probably do not want to use this function. If you want to use slice objects - in versions of Python prior to 2.3, you would probably do well to incorporate - the source of :cfunc:`PySlice_GetIndicesEx`, suitably renamed, in the source of - your extension. - - -.. cfunction:: int PySlice_GetIndicesEx(PySliceObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength) - - Usable replacement for :cfunc:`PySlice_GetIndices`. Retrieve the start, stop, - and step indices from the slice object *slice* assuming a sequence of length - *length*, and store the length of the slice in *slicelength*. Out of bounds - indices are clipped in a manner consistent with the handling of normal slices. - - Returns 0 on success and -1 on error with exception set. - - -.. _weakrefobjects: - -Weak Reference Objects ----------------------- - -Python supports *weak references* as first-class objects. There are two -specific object types which directly implement weak references. The first is a -simple reference object, and the second acts as a proxy for the original object -as much as it can. - - -.. cfunction:: int PyWeakref_Check(ob) - - Return true if *ob* is either a reference or proxy object. - - -.. cfunction:: int PyWeakref_CheckRef(ob) - - Return true if *ob* is a reference object. - - -.. cfunction:: int PyWeakref_CheckProxy(ob) - - Return true if *ob* is a proxy object. - - -.. cfunction:: PyObject* PyWeakref_NewRef(PyObject *ob, PyObject *callback) - - Return a weak reference object for the object *ob*. This will always return - a new reference, but is not guaranteed to create a new object; an existing - reference object may be returned. The second parameter, *callback*, can be a - callable object that receives notification when *ob* is garbage collected; it - should accept a single parameter, which will be the weak reference object - itself. *callback* may also be ``None`` or *NULL*. If *ob* is not a - weakly-referencable object, or if *callback* is not callable, ``None``, or - *NULL*, this will return *NULL* and raise :exc:`TypeError`. - - -.. cfunction:: PyObject* PyWeakref_NewProxy(PyObject *ob, PyObject *callback) - - Return a weak reference proxy object for the object *ob*. This will always - return a new reference, but is not guaranteed to create a new object; an - existing proxy object may be returned. The second parameter, *callback*, can - be a callable object that receives notification when *ob* is garbage - collected; it should accept a single parameter, which will be the weak - reference object itself. *callback* may also be ``None`` or *NULL*. If *ob* - is not a weakly-referencable object, or if *callback* is not callable, - ``None``, or *NULL*, this will return *NULL* and raise :exc:`TypeError`. - - -.. cfunction:: PyObject* PyWeakref_GetObject(PyObject *ref) - - Return the referenced object from a weak reference, *ref*. If the referent is - no longer live, returns ``None``. - - -.. cfunction:: PyObject* PyWeakref_GET_OBJECT(PyObject *ref) - - Similar to :cfunc:`PyWeakref_GetObject`, but implemented as a macro that does no - error checking. - - -.. _cobjects: - -CObjects --------- - -.. index:: object: CObject - -Refer to *Extending and Embedding the Python Interpreter*, section 1.12, -"Providing a C API for an Extension Module," for more information on using these -objects. - - -.. ctype:: PyCObject - - This subtype of :ctype:`PyObject` represents an opaque value, useful for C - extension modules who need to pass an opaque value (as a :ctype:`void\*` - pointer) through Python code to other C code. It is often used to make a C - function pointer defined in one module available to other modules, so the - regular import mechanism can be used to access C APIs defined in dynamically - loaded modules. - - -.. cfunction:: int PyCObject_Check(PyObject *p) - - Return true if its argument is a :ctype:`PyCObject`. - - -.. cfunction:: PyObject* PyCObject_FromVoidPtr(void* cobj, void (*destr)(void *)) - - Create a :ctype:`PyCObject` from the ``void *`` *cobj*. The *destr* function - will be called when the object is reclaimed, unless it is *NULL*. - - -.. cfunction:: PyObject* PyCObject_FromVoidPtrAndDesc(void* cobj, void* desc, void (*destr)(void *, void *)) - - Create a :ctype:`PyCObject` from the :ctype:`void \*` *cobj*. The *destr* - function will be called when the object is reclaimed. The *desc* argument can - be used to pass extra callback data for the destructor function. - - -.. cfunction:: void* PyCObject_AsVoidPtr(PyObject* self) - - Return the object :ctype:`void \*` that the :ctype:`PyCObject` *self* was - created with. - - -.. cfunction:: void* PyCObject_GetDesc(PyObject* self) - - Return the description :ctype:`void \*` that the :ctype:`PyCObject` *self* was - created with. - - -.. cfunction:: int PyCObject_SetVoidPtr(PyObject* self, void* cobj) - - Set the void pointer inside *self* to *cobj*. The :ctype:`PyCObject` must not - have an associated destructor. Return true on success, false on failure. - - -.. _cell-objects: - -Cell Objects ------------- - -"Cell" objects are used to implement variables referenced by multiple scopes. -For each such variable, a cell object is created to store the value; the local -variables of each stack frame that references the value contains a reference to -the cells from outer scopes which also use that variable. When the value is -accessed, the value contained in the cell is used instead of the cell object -itself. This de-referencing of the cell object requires support from the -generated byte-code; these are not automatically de-referenced when accessed. -Cell objects are not likely to be useful elsewhere. - - -.. ctype:: PyCellObject - - The C structure used for cell objects. - - -.. cvar:: PyTypeObject PyCell_Type - - The type object corresponding to cell objects. - - -.. cfunction:: int PyCell_Check(ob) - - Return true if *ob* is a cell object; *ob* must not be *NULL*. - - -.. cfunction:: PyObject* PyCell_New(PyObject *ob) - - Create and return a new cell object containing the value *ob*. The parameter may - be *NULL*. - - -.. cfunction:: PyObject* PyCell_Get(PyObject *cell) - - Return the contents of the cell *cell*. - - -.. cfunction:: PyObject* PyCell_GET(PyObject *cell) - - Return the contents of the cell *cell*, but without checking that *cell* is - non-*NULL* and a cell object. - - -.. cfunction:: int PyCell_Set(PyObject *cell, PyObject *value) - - Set the contents of the cell object *cell* to *value*. This releases the - reference to any current content of the cell. *value* may be *NULL*. *cell* - must be non-*NULL*; if it is not a cell object, ``-1`` will be returned. On - success, ``0`` will be returned. - - -.. cfunction:: void PyCell_SET(PyObject *cell, PyObject *value) - - Sets the value of the cell object *cell* to *value*. No reference counts are - adjusted, and no checks are made for safety; *cell* must be non-*NULL* and must - be a cell object. - - -.. _gen-objects: - -Generator Objects ------------------ - -Generator objects are what Python uses to implement generator iterators. They -are normally created by iterating over a function that yields values, rather -than explicitly calling :cfunc:`PyGen_New`. - - -.. ctype:: PyGenObject - - The C structure used for generator objects. - - -.. cvar:: PyTypeObject PyGen_Type - - The type object corresponding to generator objects - - -.. cfunction:: int PyGen_Check(ob) - - Return true if *ob* is a generator object; *ob* must not be *NULL*. - - -.. cfunction:: int PyGen_CheckExact(ob) - - Return true if *ob*'s type is *PyGen_Type* is a generator object; *ob* must not - be *NULL*. - - -.. cfunction:: PyObject* PyGen_New(PyFrameObject *frame) - - Create and return a new generator object based on the *frame* object. A - reference to *frame* is stolen by this function. The parameter must not be - *NULL*. - - -.. _datetimeobjects: - -DateTime Objects ----------------- - -Various date and time objects are supplied by the :mod:`datetime` module. -Before using any of these functions, the header file :file:`datetime.h` must be -included in your source (note that this is not included by :file:`Python.h`), -and the macro :cfunc:`PyDateTime_IMPORT` must be invoked. The macro puts a -pointer to a C structure into a static variable, ``PyDateTimeAPI``, that is -used by the following macros. - -Type-check macros: - -.. cfunction:: int PyDate_Check(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_DateType` or a subtype of - :cdata:`PyDateTime_DateType`. *ob* must not be *NULL*. - - -.. cfunction:: int PyDate_CheckExact(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_DateType`. *ob* must not be - *NULL*. - - -.. cfunction:: int PyDateTime_Check(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_DateTimeType` or a subtype of - :cdata:`PyDateTime_DateTimeType`. *ob* must not be *NULL*. - - -.. cfunction:: int PyDateTime_CheckExact(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_DateTimeType`. *ob* must not - be *NULL*. - - -.. cfunction:: int PyTime_Check(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_TimeType` or a subtype of - :cdata:`PyDateTime_TimeType`. *ob* must not be *NULL*. - - -.. cfunction:: int PyTime_CheckExact(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_TimeType`. *ob* must not be - *NULL*. - - -.. cfunction:: int PyDelta_Check(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_DeltaType` or a subtype of - :cdata:`PyDateTime_DeltaType`. *ob* must not be *NULL*. - - -.. cfunction:: int PyDelta_CheckExact(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_DeltaType`. *ob* must not be - *NULL*. - - -.. cfunction:: int PyTZInfo_Check(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_TZInfoType` or a subtype of - :cdata:`PyDateTime_TZInfoType`. *ob* must not be *NULL*. - - -.. cfunction:: int PyTZInfo_CheckExact(PyObject *ob) - - Return true if *ob* is of type :cdata:`PyDateTime_TZInfoType`. *ob* must not be - *NULL*. - - -Macros to create objects: - -.. cfunction:: PyObject* PyDate_FromDate(int year, int month, int day) - - Return a ``datetime.date`` object with the specified year, month and day. - - -.. cfunction:: PyObject* PyDateTime_FromDateAndTime(int year, int month, int day, int hour, int minute, int second, int usecond) - - Return a ``datetime.datetime`` object with the specified year, month, day, hour, - minute, second and microsecond. - - -.. cfunction:: PyObject* PyTime_FromTime(int hour, int minute, int second, int usecond) - - Return a ``datetime.time`` object with the specified hour, minute, second and - microsecond. - - -.. cfunction:: PyObject* PyDelta_FromDSU(int days, int seconds, int useconds) - - Return a ``datetime.timedelta`` object representing the given number of days, - seconds and microseconds. Normalization is performed so that the resulting - number of microseconds and seconds lie in the ranges documented for - ``datetime.timedelta`` objects. - - -Macros to extract fields from date objects. The argument must be an instance of -:cdata:`PyDateTime_Date`, including subclasses (such as -:cdata:`PyDateTime_DateTime`). The argument must not be *NULL*, and the type is -not checked: - -.. cfunction:: int PyDateTime_GET_YEAR(PyDateTime_Date *o) - - Return the year, as a positive int. - - -.. cfunction:: int PyDateTime_GET_MONTH(PyDateTime_Date *o) - - Return the month, as an int from 1 through 12. - - -.. cfunction:: int PyDateTime_GET_DAY(PyDateTime_Date *o) - - Return the day, as an int from 1 through 31. - - -Macros to extract fields from datetime objects. The argument must be an -instance of :cdata:`PyDateTime_DateTime`, including subclasses. The argument -must not be *NULL*, and the type is not checked: - -.. cfunction:: int PyDateTime_DATE_GET_HOUR(PyDateTime_DateTime *o) - - Return the hour, as an int from 0 through 23. - - -.. cfunction:: int PyDateTime_DATE_GET_MINUTE(PyDateTime_DateTime *o) - - Return the minute, as an int from 0 through 59. - - -.. cfunction:: int PyDateTime_DATE_GET_SECOND(PyDateTime_DateTime *o) - - Return the second, as an int from 0 through 59. - - -.. cfunction:: int PyDateTime_DATE_GET_MICROSECOND(PyDateTime_DateTime *o) - - Return the microsecond, as an int from 0 through 999999. - - -Macros to extract fields from time objects. The argument must be an instance of -:cdata:`PyDateTime_Time`, including subclasses. The argument must not be *NULL*, -and the type is not checked: - -.. cfunction:: int PyDateTime_TIME_GET_HOUR(PyDateTime_Time *o) - - Return the hour, as an int from 0 through 23. - - -.. cfunction:: int PyDateTime_TIME_GET_MINUTE(PyDateTime_Time *o) - - Return the minute, as an int from 0 through 59. - - -.. cfunction:: int PyDateTime_TIME_GET_SECOND(PyDateTime_Time *o) - - Return the second, as an int from 0 through 59. - - -.. cfunction:: int PyDateTime_TIME_GET_MICROSECOND(PyDateTime_Time *o) - - Return the microsecond, as an int from 0 through 999999. - - -Macros for the convenience of modules implementing the DB API: - -.. cfunction:: PyObject* PyDateTime_FromTimestamp(PyObject *args) - - Create and return a new ``datetime.datetime`` object given an argument tuple - suitable for passing to ``datetime.datetime.fromtimestamp()``. - - -.. cfunction:: PyObject* PyDate_FromTimestamp(PyObject *args) - - Create and return a new ``datetime.date`` object given an argument tuple - suitable for passing to ``datetime.date.fromtimestamp()``. - - -.. _setobjects: - -Set Objects ------------ - -.. sectionauthor:: Raymond D. Hettinger <python@rcn.com> - - -.. index:: - object: set - object: frozenset - -This section details the public API for :class:`set` and :class:`frozenset` -objects. Any functionality not listed below is best accessed using the either -the abstract object protocol (including :cfunc:`PyObject_CallMethod`, -:cfunc:`PyObject_RichCompareBool`, :cfunc:`PyObject_Hash`, -:cfunc:`PyObject_Repr`, :cfunc:`PyObject_IsTrue`, :cfunc:`PyObject_Print`, and -:cfunc:`PyObject_GetIter`) or the abstract number protocol (including -:cfunc:`PyNumber_And`, :cfunc:`PyNumber_Subtract`, :cfunc:`PyNumber_Or`, -:cfunc:`PyNumber_Xor`, :cfunc:`PyNumber_InPlaceAnd`, -:cfunc:`PyNumber_InPlaceSubtract`, :cfunc:`PyNumber_InPlaceOr`, and -:cfunc:`PyNumber_InPlaceXor`). - - -.. ctype:: PySetObject - - This subtype of :ctype:`PyObject` is used to hold the internal data for both - :class:`set` and :class:`frozenset` objects. It is like a :ctype:`PyDictObject` - in that it is a fixed size for small sets (much like tuple storage) and will - point to a separate, variable sized block of memory for medium and large sized - sets (much like list storage). None of the fields of this structure should be - considered public and are subject to change. All access should be done through - the documented API rather than by manipulating the values in the structure. - - -.. cvar:: PyTypeObject PySet_Type - - This is an instance of :ctype:`PyTypeObject` representing the Python - :class:`set` type. - - -.. cvar:: PyTypeObject PyFrozenSet_Type - - This is an instance of :ctype:`PyTypeObject` representing the Python - :class:`frozenset` type. - -The following type check macros work on pointers to any Python object. Likewise, -the constructor functions work with any iterable Python object. - - -.. cfunction:: int PyAnySet_Check(PyObject *p) - - Return true if *p* is a :class:`set` object, a :class:`frozenset` object, or an - instance of a subtype. - - -.. cfunction:: int PyAnySet_CheckExact(PyObject *p) - - Return true if *p* is a :class:`set` object or a :class:`frozenset` object but - not an instance of a subtype. - - -.. cfunction:: int PyFrozenSet_CheckExact(PyObject *p) - - Return true if *p* is a :class:`frozenset` object but not an instance of a - subtype. - - -.. cfunction:: PyObject* PySet_New(PyObject *iterable) - - Return a new :class:`set` containing objects returned by the *iterable*. The - *iterable* may be *NULL* to create a new empty set. Return the new set on - success or *NULL* on failure. Raise :exc:`TypeError` if *iterable* is not - actually iterable. The constructor is also useful for copying a set - (``c=set(s)``). - - -.. cfunction:: PyObject* PyFrozenSet_New(PyObject *iterable) - - Return a new :class:`frozenset` containing objects returned by the *iterable*. - The *iterable* may be *NULL* to create a new empty frozenset. Return the new - set on success or *NULL* on failure. Raise :exc:`TypeError` if *iterable* is - not actually iterable. - -The following functions and macros are available for instances of :class:`set` -or :class:`frozenset` or instances of their subtypes. - - -.. cfunction:: Py_ssize_t PySet_Size(PyObject *anyset) - - .. index:: builtin: len - - Return the length of a :class:`set` or :class:`frozenset` object. Equivalent to - ``len(anyset)``. Raises a :exc:`PyExc_SystemError` if *anyset* is not a - :class:`set`, :class:`frozenset`, or an instance of a subtype. - - -.. cfunction:: Py_ssize_t PySet_GET_SIZE(PyObject *anyset) - - Macro form of :cfunc:`PySet_Size` without error checking. - - -.. cfunction:: int PySet_Contains(PyObject *anyset, PyObject *key) - - Return 1 if found, 0 if not found, and -1 if an error is encountered. Unlike - the Python :meth:`__contains__` method, this function does not automatically - convert unhashable sets into temporary frozensets. Raise a :exc:`TypeError` if - the *key* is unhashable. Raise :exc:`PyExc_SystemError` if *anyset* is not a - :class:`set`, :class:`frozenset`, or an instance of a subtype. - -The following functions are available for instances of :class:`set` or its -subtypes but not for instances of :class:`frozenset` or its subtypes. - - -.. cfunction:: int PySet_Add(PyObject *set, PyObject *key) - - Add *key* to a :class:`set` instance. Does not apply to :class:`frozenset` - instances. Return 0 on success or -1 on failure. Raise a :exc:`TypeError` if - the *key* is unhashable. Raise a :exc:`MemoryError` if there is no room to grow. - Raise a :exc:`SystemError` if *set* is an not an instance of :class:`set` or its - subtype. - - -.. cfunction:: int PySet_Discard(PyObject *set, PyObject *key) - - Return 1 if found and removed, 0 if not found (no action taken), and -1 if an - error is encountered. Does not raise :exc:`KeyError` for missing keys. Raise a - :exc:`TypeError` if the *key* is unhashable. Unlike the Python :meth:`discard` - method, this function does not automatically convert unhashable sets into - temporary frozensets. Raise :exc:`PyExc_SystemError` if *set* is an not an - instance of :class:`set` or its subtype. - - -.. cfunction:: PyObject* PySet_Pop(PyObject *set) - - Return a new reference to an arbitrary object in the *set*, and removes the - object from the *set*. Return *NULL* on failure. Raise :exc:`KeyError` if the - set is empty. Raise a :exc:`SystemError` if *set* is an not an instance of - :class:`set` or its subtype. - - -.. cfunction:: int PySet_Clear(PyObject *set) - - Empty an existing set of all elements. - +.. toctree:: + + set.rst + function.rst + method.rst + file.rst + module.rst + iterator.rst + descriptor.rst + slice.rst + weakref.rst + cobject.rst + cell.rst + gen.rst + datetime.rst |