
Object Protocol
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PyObject* Py_NotImplemented

   The ``NotImplemented`` singleton, used to signal that an operation
   is not implemented for the given type combination.

Py_RETURN_NOTIMPLEMENTED

   Properly handle returning ``Py_NotImplemented`` from within a C
   function (that is, increment the reference count of NotImplemented
   and return it).

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 ``Py_PRINT_RAW``; if given, the
   ``str()`` of the object is written instead of the ``repr()``.

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.

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.

PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name)
    Return value: New reference.

   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``.

PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name)
    Return value: New reference.

   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``.

PyObject* PyObject_GenericGetAttr(PyObject *o, PyObject *name)

   Generic attribute getter function that is meant to be put into a
   type object's ``tp_getattro`` slot.  It looks for a descriptor in
   the dictionary of classes in the object's MRO as well as an
   attribute in the object's ``__dict__`` (if present).  As outlined
   in *Implementing Descriptors*, data descriptors take preference
   over instance attributes, while non-data descriptors don't.
   Otherwise, an ``AttributeError`` is raised.

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``.

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``.

int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)

   Generic attribute setter function that is meant to be put into a
   type object's ``tp_setattro`` slot.  It looks for a data descriptor
   in the dictionary of classes in the object's MRO, and if found it
   takes preference over setting the attribute in the instance
   dictionary. Otherwise, the attribute is set in the object's
   ``__dict__`` (if present).  Otherwise, an ``AttributeError`` is
   raised and ``-1`` is returned.

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``.

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``.

PyObject* PyType_GenericGetDict(PyObject *o, void *context)

   A generic implementation for the getter of a ``__dict__``
   descriptor. It creates the dictionary if necessary.

   New in version 3.3.

int PyType_GenericSetDict(PyObject *o, void *context)

   A generic implementation for the setter of a ``__dict__``
   descriptor. This implementation does not allow the dictionary to be
   deleted.

   New in version 3.3.

PyObject* PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)
    Return value: New reference.

   Compare the values of *o1* and *o2* using the operation specified
   by *opid*, which must be one of ``Py_LT``, ``Py_LE``, ``Py_EQ``,
   ``Py_NE``, ``Py_GT``, or ``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.

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 ``Py_LT``, ``Py_LE``, ``Py_EQ``,
   ``Py_NE``, ``Py_GT``, or ``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*.

Note: If *o1* and *o2* are the same object, ``PyObject_RichCompareBool()``
  will always return ``1`` for ``Py_EQ`` and ``0`` for ``Py_NE``.

PyObject* PyObject_Repr(PyObject *o)
    Return value: New reference.

   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
   ``repr()`` built-in function.

PyObject* PyObject_ASCII(PyObject *o)

   As ``PyObject_Repr()``, compute a string representation of object
   *o*, but escape the non-ASCII characters in the string returned by
   ``PyObject_Repr()`` with ``\x``, ``\u`` or ``\U`` escapes.  This
   generates a string similar to that returned by ``PyObject_Repr()``
   in Python 2. Called by the ``ascii()`` built-in function.

PyObject* PyObject_Str(PyObject *o)
    Return value: New reference.

   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
   ``str()`` built-in function and, therefore, by the ``print()``
   function.

PyObject* PyObject_Bytes(PyObject *o)

   Compute a bytes representation of object *o*.  *NULL* is returned
   on failure and a bytes object on success.  This is equivalent to
   the Python expression ``bytes(o)``, when *o* is not an integer.
   Unlike ``bytes(o)``, a TypeError is raised when *o* is an integer
   instead of a zero-initialized bytes object.

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, ``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 ``__class__``
   attribute --- the class relationship of the value of that attribute
   with *cls* will be used to determine the result of this function.

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 ``A`` and ``B`` are class objects, ``B``
is a subclass of ``A`` if it inherits from ``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*,
``PyObject_IsSubclass()`` returns true.  If *A* and *B* are different
objects, *B*'s ``__bases__`` attribute is searched in a depth-first
fashion for *A* --- the presence of the ``__bases__`` attribute is
considered sufficient for this determination.

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.

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.

PyObject* PyObject_Call(PyObject *callable_object, PyObject *args, PyObject *kw)
    Return value: New reference.

   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
   ``callable_object(*args, **kw)``.

PyObject* PyObject_CallObject(PyObject *callable_object, PyObject *args)
    Return value: New reference.

   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
   ``callable_object(*args)``.

PyObject* PyObject_CallFunction(PyObject *callable, char *format, ...)
    Return value: New reference.

   Call a callable Python object *callable*, with a variable number of
   C arguments. The C arguments are described using a
   ``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 ``callable(*args)``. Note that if you only
   pass ``PyObject *`` args, ``PyObject_CallFunctionObjArgs()`` is a
   faster alternative.

PyObject* PyObject_CallMethod(PyObject *o, char *method, char *format, ...)
    Return value: New reference.

   Call the method named *method* of object *o* with a variable number
   of C arguments.  The C arguments are described by a
   ``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 ``PyObject *`` args,
   ``PyObject_CallMethodObjArgs()`` is a faster alternative.

PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL)
    Return value: New reference.

   Call a callable Python object *callable*, with a variable number of
   ``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.

PyObject* PyObject_CallMethodObjArgs(PyObject *o, PyObject *name, ..., NULL)
    Return value: New reference.

   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 ``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.

Py_hash_t PyObject_Hash(PyObject *o)

   Compute and return the hash value of an object *o*.  On failure,
   return ``-1``. This is the equivalent of the Python expression
   ``hash(o)``.

   Changed in version 3.2: The return type is now Py_hash_t.  This is
   a signed integer the same size as Py_ssize_t.

Py_hash_t PyObject_HashNotImplemented(PyObject *o)

   Set a ``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.

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``.

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``.

PyObject* PyObject_Type(PyObject *o)
    Return value: New reference.

   When *o* is non-*NULL*, returns a type object corresponding to the
   object type of object *o*. On failure, raises ``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 ``PyTypeObject*``, except when the incremented reference count
   is needed.

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*.

Py_ssize_t PyObject_Length(PyObject *o)
Py_ssize_t PyObject_Size(PyObject *o)

   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)``.

PyObject* PyObject_GetItem(PyObject *o, PyObject *key)
    Return value: New reference.

   Return element of *o* corresponding to the object *key* or *NULL*
   on failure. This is the equivalent of the Python expression
   ``o[key]``.

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``.

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]``.

PyObject* PyObject_Dir(PyObject *o)
    Return value: New reference.

   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 ``PyErr_Occurred()`` will return false.

PyObject* PyObject_GetIter(PyObject *o)
    Return value: New reference.

   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 ``TypeError`` and
   returns *NULL* if the object cannot be iterated.
