--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/python-2.6.1/Doc/c-api/object.rst Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,375 @@
+.. highlightlang:: c
+
+.. _object:
+
+Object Protocol
+===============
+
+
+.. cfunction:: int PyObject_Print(PyObject *o, FILE *fp, int flags)
+
+ Print an object *o*, on file *fp*. Returns ``-1`` on error. The flags argument
+ is used to enable certain printing options. The only option currently supported
+ is :const:`Py_PRINT_RAW`; if given, the :func:`str` of the object is written
+ instead of the :func:`repr`.
+
+
+.. cfunction:: int PyObject_HasAttr(PyObject *o, PyObject *attr_name)
+
+ Returns ``1`` if *o* has the attribute *attr_name*, and ``0`` otherwise. This
+ is equivalent to the Python expression ``hasattr(o, attr_name)``. This function
+ always succeeds.
+
+
+.. cfunction:: int PyObject_HasAttrString(PyObject *o, const char *attr_name)
+
+ Returns ``1`` if *o* has the attribute *attr_name*, and ``0`` otherwise. This
+ is equivalent to the Python expression ``hasattr(o, attr_name)``. This function
+ always succeeds.
+
+
+.. cfunction:: PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name)
+
+ Retrieve an attribute named *attr_name* from object *o*. Returns the attribute
+ value on success, or *NULL* on failure. This is the equivalent of the Python
+ expression ``o.attr_name``.
+
+
+.. cfunction:: PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name)
+
+ Retrieve an attribute named *attr_name* from object *o*. Returns the attribute
+ value on success, or *NULL* on failure. This is the equivalent of the Python
+ expression ``o.attr_name``.
+
+
+.. cfunction:: int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v)
+
+ Set the value of the attribute named *attr_name*, for object *o*, to the value
+ *v*. Returns ``-1`` on failure. This is the equivalent of the Python statement
+ ``o.attr_name = v``.
+
+
+.. cfunction:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
+
+ Set the value of the attribute named *attr_name*, for object *o*, to the value
+ *v*. Returns ``-1`` on failure. This is the equivalent of the Python statement
+ ``o.attr_name = v``.
+
+
+.. cfunction:: int PyObject_DelAttr(PyObject *o, PyObject *attr_name)
+
+ Delete attribute named *attr_name*, for object *o*. Returns ``-1`` on failure.
+ This is the equivalent of the Python statement ``del o.attr_name``.
+
+
+.. cfunction:: int PyObject_DelAttrString(PyObject *o, const char *attr_name)
+
+ Delete attribute named *attr_name*, for object *o*. Returns ``-1`` on failure.
+ This is the equivalent of the Python statement ``del o.attr_name``.
+
+
+.. cfunction:: PyObject* PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)
+
+ Compare the values of *o1* and *o2* using the operation specified by *opid*,
+ which must be one of :const:`Py_LT`, :const:`Py_LE`, :const:`Py_EQ`,
+ :const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``,
+ ``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. This is the equivalent of
+ the Python expression ``o1 op o2``, where ``op`` is the operator corresponding
+ to *opid*. Returns the value of the comparison on success, or *NULL* on failure.
+
+
+.. cfunction:: int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid)
+
+ Compare the values of *o1* and *o2* using the operation specified by *opid*,
+ which must be one of :const:`Py_LT`, :const:`Py_LE`, :const:`Py_EQ`,
+ :const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``,
+ ``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. Returns ``-1`` on error,
+ ``0`` if the result is false, ``1`` otherwise. This is the equivalent of the
+ Python expression ``o1 op o2``, where ``op`` is the operator corresponding to
+ *opid*.
+
+
+.. cfunction:: int PyObject_Cmp(PyObject *o1, PyObject *o2, int *result)
+
+ .. index:: builtin: cmp
+
+ Compare the values of *o1* and *o2* using a routine provided by *o1*, if one
+ exists, otherwise with a routine provided by *o2*. The result of the comparison
+ is returned in *result*. Returns ``-1`` on failure. This is the equivalent of
+ the Python statement ``result = cmp(o1, o2)``.
+
+
+.. cfunction:: int PyObject_Compare(PyObject *o1, PyObject *o2)
+
+ .. index:: builtin: cmp
+
+ Compare the values of *o1* and *o2* using a routine provided by *o1*, if one
+ exists, otherwise with a routine provided by *o2*. Returns the result of the
+ comparison on success. On error, the value returned is undefined; use
+ :cfunc:`PyErr_Occurred` to detect an error. This is equivalent to the Python
+ expression ``cmp(o1, o2)``.
+
+
+.. cfunction:: PyObject* PyObject_Repr(PyObject *o)
+
+ .. index:: builtin: repr
+
+ Compute a string representation of object *o*. Returns the string
+ representation on success, *NULL* on failure. This is the equivalent of the
+ Python expression ``repr(o)``. Called by the :func:`repr` built-in function and
+ by reverse quotes.
+
+
+.. cfunction:: PyObject* PyObject_Str(PyObject *o)
+
+ .. index:: builtin: str
+
+ Compute a string representation of object *o*. Returns the string
+ representation on success, *NULL* on failure. This is the equivalent of the
+ Python expression ``str(o)``. Called by the :func:`str` built-in function and
+ by the :keyword:`print` statement.
+
+
+.. cfunction:: PyObject* PyObject_Bytes(PyObject *o)
+
+ .. index:: builtin: bytes
+
+ Compute a bytes representation of object *o*. In 2.x, this is just a alias
+ for :cfunc:`PyObject_Str`.
+
+
+.. cfunction:: PyObject* PyObject_Unicode(PyObject *o)
+
+ .. index:: builtin: unicode
+
+ Compute a Unicode string representation of object *o*. Returns the Unicode
+ string representation on success, *NULL* on failure. This is the equivalent of
+ the Python expression ``unicode(o)``. Called by the :func:`unicode` built-in
+ function.
+
+
+.. cfunction:: int PyObject_IsInstance(PyObject *inst, PyObject *cls)
+
+ Returns ``1`` if *inst* is an instance of the class *cls* or a subclass of
+ *cls*, or ``0`` if not. On error, returns ``-1`` and sets an exception. If
+ *cls* is a type object rather than a class object, :cfunc:`PyObject_IsInstance`
+ returns ``1`` if *inst* is of type *cls*. If *cls* is a tuple, the check will
+ be done against every entry in *cls*. The result will be ``1`` when at least one
+ of the checks returns ``1``, otherwise it will be ``0``. If *inst* is not a
+ class instance and *cls* is neither a type object, nor a class object, nor a
+ tuple, *inst* must have a :attr:`__class__` attribute --- the class relationship
+ of the value of that attribute with *cls* will be used to determine the result
+ of this function.
+
+ .. versionadded:: 2.1
+
+ .. versionchanged:: 2.2
+ Support for a tuple as the second argument added.
+
+Subclass determination is done in a fairly straightforward way, but includes a
+wrinkle that implementors of extensions to the class system may want to be aware
+of. If :class:`A` and :class:`B` are class objects, :class:`B` is a subclass of
+:class:`A` if it inherits from :class:`A` either directly or indirectly. If
+either is not a class object, a more general mechanism is used to determine the
+class relationship of the two objects. When testing if *B* is a subclass of
+*A*, if *A* is *B*, :cfunc:`PyObject_IsSubclass` returns true. If *A* and *B*
+are different objects, *B*'s :attr:`__bases__` attribute is searched in a
+depth-first fashion for *A* --- the presence of the :attr:`__bases__` attribute
+is considered sufficient for this determination.
+
+
+.. cfunction:: int PyObject_IsSubclass(PyObject *derived, PyObject *cls)
+
+ Returns ``1`` if the class *derived* is identical to or derived from the class
+ *cls*, otherwise returns ``0``. In case of an error, returns ``-1``. If *cls*
+ is a tuple, the check will be done against every entry in *cls*. The result will
+ be ``1`` when at least one of the checks returns ``1``, otherwise it will be
+ ``0``. If either *derived* or *cls* is not an actual class object (or tuple),
+ this function uses the generic algorithm described above.
+
+ .. versionadded:: 2.1
+
+ .. versionchanged:: 2.3
+ Older versions of Python did not support a tuple as the second argument.
+
+
+.. cfunction:: int PyCallable_Check(PyObject *o)
+
+ Determine if the object *o* is callable. Return ``1`` if the object is callable
+ and ``0`` otherwise. This function always succeeds.
+
+
+.. cfunction:: PyObject* PyObject_Call(PyObject *callable_object, PyObject *args, PyObject *kw)
+
+ .. index:: builtin: apply
+
+ Call a callable Python object *callable_object*, with arguments given by the
+ tuple *args*, and named arguments given by the dictionary *kw*. If no named
+ arguments are needed, *kw* may be *NULL*. *args* must not be *NULL*, use an
+ empty tuple if no arguments are needed. Returns the result of the call on
+ success, or *NULL* on failure. This is the equivalent of the Python expression
+ ``apply(callable_object, args, kw)`` or ``callable_object(*args, **kw)``.
+
+ .. versionadded:: 2.2
+
+
+.. cfunction:: PyObject* PyObject_CallObject(PyObject *callable_object, PyObject *args)
+
+ .. index:: builtin: apply
+
+ Call a callable Python object *callable_object*, with arguments given by the
+ tuple *args*. If no arguments are needed, then *args* may be *NULL*. Returns
+ the result of the call on success, or *NULL* on failure. This is the equivalent
+ of the Python expression ``apply(callable_object, args)`` or
+ ``callable_object(*args)``.
+
+
+.. cfunction:: PyObject* PyObject_CallFunction(PyObject *callable, char *format, ...)
+
+ .. index:: builtin: apply
+
+ Call a callable Python object *callable*, with a variable number of C arguments.
+ The C arguments are described using a :cfunc:`Py_BuildValue` style format
+ string. The format may be *NULL*, indicating that no arguments are provided.
+ Returns the result of the call on success, or *NULL* on failure. This is the
+ equivalent of the Python expression ``apply(callable, args)`` or
+ ``callable(*args)``. Note that if you only pass :ctype:`PyObject \*` args,
+ :cfunc:`PyObject_CallFunctionObjArgs` is a faster alternative.
+
+
+.. cfunction:: PyObject* PyObject_CallMethod(PyObject *o, char *method, char *format, ...)
+
+ Call the method named *method* of object *o* with a variable number of C
+ arguments. The C arguments are described by a :cfunc:`Py_BuildValue` format
+ string that should produce a tuple. The format may be *NULL*, indicating that
+ no arguments are provided. Returns the result of the call on success, or *NULL*
+ on failure. This is the equivalent of the Python expression ``o.method(args)``.
+ Note that if you only pass :ctype:`PyObject \*` args,
+ :cfunc:`PyObject_CallMethodObjArgs` is a faster alternative.
+
+
+.. cfunction:: PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL)
+
+ Call a callable Python object *callable*, with a variable number of
+ :ctype:`PyObject\*` arguments. The arguments are provided as a variable number
+ of parameters followed by *NULL*. Returns the result of the call on success, or
+ *NULL* on failure.
+
+ .. versionadded:: 2.2
+
+
+.. cfunction:: PyObject* PyObject_CallMethodObjArgs(PyObject *o, PyObject *name, ..., NULL)
+
+ Calls a method of the object *o*, where the name of the method is given as a
+ Python string object in *name*. It is called with a variable number of
+ :ctype:`PyObject\*` arguments. The arguments are provided as a variable number
+ of parameters followed by *NULL*. Returns the result of the call on success, or
+ *NULL* on failure.
+
+ .. versionadded:: 2.2
+
+
+.. cfunction:: long PyObject_Hash(PyObject *o)
+
+ .. index:: builtin: hash
+
+ Compute and return the hash value of an object *o*. On failure, return ``-1``.
+ This is the equivalent of the Python expression ``hash(o)``.
+
+
+.. cfunction:: long PyObject_HashNotImplemented(PyObject *o)
+
+ Set a :exc:`TypeError` indicating that ``type(o)`` is not hashable and return ``-1``.
+ This function receives special treatment when stored in a ``tp_hash`` slot,
+ allowing a type to explicitly indicate to the interpreter that it is not
+ hashable.
+
+ .. versionadded:: 2.6
+
+
+.. cfunction:: int PyObject_IsTrue(PyObject *o)
+
+ Returns ``1`` if the object *o* is considered to be true, and ``0`` otherwise.
+ This is equivalent to the Python expression ``not not o``. On failure, return
+ ``-1``.
+
+
+.. cfunction:: int PyObject_Not(PyObject *o)
+
+ Returns ``0`` if the object *o* is considered to be true, and ``1`` otherwise.
+ This is equivalent to the Python expression ``not o``. On failure, return
+ ``-1``.
+
+
+.. cfunction:: PyObject* PyObject_Type(PyObject *o)
+
+ .. index:: builtin: type
+
+ When *o* is non-*NULL*, returns a type object corresponding to the object type
+ of object *o*. On failure, raises :exc:`SystemError` and returns *NULL*. This
+ is equivalent to the Python expression ``type(o)``. This function increments the
+ reference count of the return value. There's really no reason to use this
+ function instead of the common expression ``o->ob_type``, which returns a
+ pointer of type :ctype:`PyTypeObject\*`, except when the incremented reference
+ count is needed.
+
+
+.. cfunction:: int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)
+
+ Return true if the object *o* is of type *type* or a subtype of *type*. Both
+ parameters must be non-*NULL*.
+
+ .. versionadded:: 2.2
+
+
+.. cfunction:: Py_ssize_t PyObject_Length(PyObject *o)
+ Py_ssize_t PyObject_Size(PyObject *o)
+
+ .. index:: builtin: len
+
+ Return the length of object *o*. If the object *o* provides either the sequence
+ and mapping protocols, the sequence length is returned. On error, ``-1`` is
+ returned. This is the equivalent to the Python expression ``len(o)``.
+
+
+.. cfunction:: PyObject* PyObject_GetItem(PyObject *o, PyObject *key)
+
+ Return element of *o* corresponding to the object *key* or *NULL* on failure.
+ This is the equivalent of the Python expression ``o[key]``.
+
+
+.. cfunction:: int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)
+
+ Map the object *key* to the value *v*. Returns ``-1`` on failure. This is the
+ equivalent of the Python statement ``o[key] = v``.
+
+
+.. cfunction:: int PyObject_DelItem(PyObject *o, PyObject *key)
+
+ Delete the mapping for *key* from *o*. Returns ``-1`` on failure. This is the
+ equivalent of the Python statement ``del o[key]``.
+
+
+.. cfunction:: int PyObject_AsFileDescriptor(PyObject *o)
+
+ Derives a file descriptor from a Python object. If the object is an integer or
+ long integer, its value is returned. If not, the object's :meth:`fileno` method
+ is called if it exists; the method must return an integer or long integer, which
+ is returned as the file descriptor value. Returns ``-1`` on failure.
+
+
+.. cfunction:: PyObject* PyObject_Dir(PyObject *o)
+
+ This is equivalent to the Python expression ``dir(o)``, returning a (possibly
+ empty) list of strings appropriate for the object argument, or *NULL* if there
+ was an error. If the argument is *NULL*, this is like the Python ``dir()``,
+ returning the names of the current locals; in this case, if no execution frame
+ is active then *NULL* is returned but :cfunc:`PyErr_Occurred` will return false.
+
+
+.. cfunction:: PyObject* PyObject_GetIter(PyObject *o)
+
+ This is equivalent to the Python expression ``iter(o)``. It returns a new
+ iterator for the object argument, or the object itself if the object is already
+ an iterator. Raises :exc:`TypeError` and returns *NULL* if the object cannot be
+ iterated.