Object Protocol
***************

PyObject *Py_GetConstant(unsigned int constant_id)
    * Parte del ABI Stabile dalla versione 3.13.*

   Get a *strong reference* to a constant.

   Set an exception and return "NULL" if *constant_id* is invalid.

   *constant_id* must be one of these constant identifiers:

   +------------------------------------------+-------+---------------------------+
   | Constant Identifier                      | Value | Returned object           |
   |==========================================|=======|===========================|
   | Py_CONSTANT_NONE                         | "0"   | "None"                    |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_FALSE                        | "1"   | "False"                   |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_TRUE                         | "2"   | "True"                    |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_ELLIPSIS                     | "3"   | "Ellipsis"                |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_NOT_IMPLEMENTED              | "4"   | "NotImplemented"          |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_ZERO                         | "5"   | "0"                       |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_ONE                          | "6"   | "1"                       |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_EMPTY_STR                    | "7"   | "''"                      |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_EMPTY_BYTES                  | "8"   | "b''"                     |
   +------------------------------------------+-------+---------------------------+
   | Py_CONSTANT_EMPTY_TUPLE                  | "9"   | "()"                      |
   +------------------------------------------+-------+---------------------------+

   Numeric values are only given for projects which cannot use the
   constant identifiers.

   Added in version 3.13.

   **Dettaglio dell’implementazione di CPython:** In CPython, all of
   these constants are *immortal*.

PyObject *Py_GetConstantBorrowed(unsigned int constant_id)
    * Parte del ABI Stabile dalla versione 3.13.*

   Similar to "Py_GetConstant()", but return a *borrowed reference*.

   This function is primarily intended for backwards compatibility:
   using "Py_GetConstant()" is recommended for new code.

   The reference is borrowed from the interpreter, and is valid until
   the interpreter finalization. .. versionadded:: 3.13

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, create a new *strong reference* to
   "NotImplemented" and return it).

Py_PRINT_RAW

   Flag to be used with multiple functions that print the object (like
   "PyObject_Print()" and "PyFile_WriteObject()"). If passed, these
   function would use the "str()" of the object instead of the
   "repr()".

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_HasAttrWithError(PyObject *o, const char *attr_name)
    * Parte del ABI Stabile dalla versione 3.13.*

   Returns "1" if *o* has the attribute *attr_name*, and "0"
   otherwise. This is equivalent to the Python expression "hasattr(o,
   attr_name)". On failure, return "-1".

   Added in version 3.13.

int PyObject_HasAttrStringWithError(PyObject *o, const char *attr_name)
    * Parte del ABI Stabile dalla versione 3.13.*

   This is the same as "PyObject_HasAttrWithError()", but *attr_name*
   is specified as a const char* UTF-8 encoded bytes string, rather
   than a PyObject*.

   Added in version 3.13.

int PyObject_HasAttr(PyObject *o, PyObject *attr_name)
    * Parte del ABI Stabile.*

   Returns "1" if *o* has the attribute *attr_name*, and "0"
   otherwise. This function always succeeds.

   Nota:

     Exceptions that occur when this calls "__getattr__()" and
     "__getattribute__()" methods are silently ignored. For proper
     error handling, use "PyObject_HasAttrWithError()",
     "PyObject_GetOptionalAttr()" or "PyObject_GetAttr()" instead.

int PyObject_HasAttrString(PyObject *o, const char *attr_name)
    * Parte del ABI Stabile.*

   This is the same as "PyObject_HasAttr()", but *attr_name* is
   specified as a const char* UTF-8 encoded bytes string, rather than
   a PyObject*.

   Nota:

     Exceptions that occur when this calls "__getattr__()" and
     "__getattribute__()" methods or while creating the temporary
     "str" object are silently ignored. For proper error handling, use
     "PyObject_HasAttrStringWithError()",
     "PyObject_GetOptionalAttrString()" or "PyObject_GetAttrString()"
     instead.

PyObject *PyObject_GetAttr(PyObject *o, PyObject *attr_name)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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".

   If the missing attribute should not be treated as a failure, you
   can use "PyObject_GetOptionalAttr()" instead.

PyObject *PyObject_GetAttrString(PyObject *o, const char *attr_name)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   This is the same as "PyObject_GetAttr()", but *attr_name* is
   specified as a const char* UTF-8 encoded bytes string, rather than
   a PyObject*.

   If the missing attribute should not be treated as a failure, you
   can use "PyObject_GetOptionalAttrString()" instead.

int PyObject_GetOptionalAttr(PyObject *obj, PyObject *attr_name, PyObject **result);
    * Parte del ABI Stabile dalla versione 3.13.*

   Variant of "PyObject_GetAttr()" which doesn't raise
   "AttributeError" if the attribute is not found.

   If the attribute is found, return "1" and set **result* to a new
   *strong reference* to the attribute. If the attribute is not found,
   return "0" and set **result* to "NULL"; the "AttributeError" is
   silenced. If an error other than "AttributeError" is raised, return
   "-1" and set **result* to "NULL".

   Added in version 3.13.

int PyObject_GetOptionalAttrString(PyObject *obj, const char *attr_name, PyObject **result);
    * Parte del ABI Stabile dalla versione 3.13.*

   This is the same as "PyObject_GetOptionalAttr()", but *attr_name*
   is specified as a const char* UTF-8 encoded bytes string, rather
   than a PyObject*.

   Added in version 3.13.

PyObject *PyObject_GenericGetAttr(PyObject *o, PyObject *name)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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)
    * Parte del ABI Stabile.*

   Set the value of the attribute named *attr_name*, for object *o*,
   to the value *v*. Raise an exception and return "-1" on failure;
   return "0" on success.  This is the equivalent of the Python
   statement "o.attr_name = v".

   If *v* is "NULL", the attribute is deleted. This behaviour is
   deprecated in favour of using "PyObject_DelAttr()", but there are
   currently no plans to remove it.

int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
    * Parte del ABI Stabile.*

   This is the same as "PyObject_SetAttr()", but *attr_name* is
   specified as a const char* UTF-8 encoded bytes string, rather than
   a PyObject*.

   If *v* is "NULL", the attribute is deleted, but this feature is
   deprecated in favour of using "PyObject_DelAttrString()".

int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)
    * Parte del ABI Stabile.*

   Generic attribute setter and deleter 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 or deleting the attribute in
   the instance dictionary. Otherwise, the attribute is set or deleted
   in the object's "__dict__" (if present). On success, "0" is
   returned, otherwise an "AttributeError" is raised and "-1" is
   returned.

int PyObject_DelAttr(PyObject *o, PyObject *attr_name)
    * Parte del ABI Stabile dalla versione 3.13.*

   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)
    * Parte del ABI Stabile dalla versione 3.13.*

   This is the same as "PyObject_DelAttr()", but *attr_name* is
   specified as a const char* UTF-8 encoded bytes string, rather than
   a PyObject*.

PyObject *PyObject_GenericGetDict(PyObject *o, void *context)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile
   dalla versione 3.10.*

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

   This function may also be called to get the "__dict__" of the
   object *o*. Pass "NULL" for *context* when calling it. Since this
   function may need to allocate memory for the dictionary, it may be
   more efficient to call "PyObject_GetAttr()" when accessing an
   attribute on the object.

   On failure, returns "NULL" with an exception set.

   Added in version 3.3.

int PyObject_GenericSetDict(PyObject *o, PyObject *value, void *context)
    * Parte del ABI Stabile dalla versione 3.7.*

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

   Added in version 3.3.

PyObject **_PyObject_GetDictPtr(PyObject *obj)

   Return a pointer to "__dict__" of the object *obj*. If there is no
   "__dict__", return "NULL" without setting an exception.

   This function may need to allocate memory for the dictionary, so it
   may be more efficient to call "PyObject_GetAttr()" when accessing
   an attribute on the object.

PyObject *PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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)
    * Parte del ABI Stabile.*

   Compare the values of *o1* and *o2* using the operation specified
   by *opid*, like "PyObject_RichCompare()", but returns "-1" on
   error, "0" if the result is false, "1" otherwise.

Nota:

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

PyObject *PyObject_Format(PyObject *obj, PyObject *format_spec)
    * Parte del ABI Stabile.*

   Format *obj* using *format_spec*. This is equivalent to the Python
   expression "format(obj, format_spec)".

   *format_spec* may be "NULL". In this case the call is equivalent to
   "format(obj)". Returns the formatted string on success, "NULL" on
   failure.

PyObject *PyObject_Repr(PyObject *o)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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.

   Cambiato nella versione 3.4: This function now includes a debug
   assertion to help ensure that it does not silently discard an
   active exception.

PyObject *PyObject_ASCII(PyObject *o)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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.

   Cambiato nella versione 3.4: This function now includes a debug
   assertion to help ensure that it does not silently discard an
   active exception.

PyObject *PyObject_Bytes(PyObject *o)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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_IsSubclass(PyObject *derived, PyObject *cls)
    * Parte del ABI Stabile.*

   Return "1" if the class *derived* is identical to or derived from
   the class *cls*, otherwise return "0".  In case of an error, return
   "-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 *cls* has a "__subclasscheck__()" method, it will be called to
   determine the subclass status as described in **PEP 3119**.
   Otherwise, *derived* is a subclass of *cls* if it is a direct or
   indirect subclass, i.e. contained in "cls.__mro__".

   Normally only class objects, i.e. instances of "type" or a derived
   class, are considered classes.  However, objects can override this
   by having a "__bases__" attribute (which must be a tuple of base
   classes).

int PyObject_IsInstance(PyObject *inst, PyObject *cls)
    * Parte del ABI Stabile.*

   Return "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 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 *cls* has a "__instancecheck__()" method, it will be called to
   determine the subclass status as described in **PEP 3119**.
   Otherwise, *inst* is an instance of *cls* if its class is a
   subclass of *cls*.

   An instance *inst* can override what is considered its class by
   having a "__class__" attribute.

   An object *cls* can override if it is considered a class, and what
   its base classes are, by having a "__bases__" attribute (which must
   be a tuple of base classes).

Py_hash_t PyObject_Hash(PyObject *o)
    * Parte del ABI Stabile.*

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

   Cambiato nella versione 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)
    * Parte del ABI Stabile.*

   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)
    * Parte del ABI Stabile.*

   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)
    * Parte del ABI Stabile.*

   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)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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 creates a new *strong reference* to the
   return value. There's really no reason to use this function instead
   of the "Py_TYPE()" function, which returns a pointer of type
   PyTypeObject*, except when a new *strong reference* is needed.

int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)

   Return non-zero if the object *o* is of type *type* or a subtype of
   *type*, and "0" otherwise.  Both parameters must be non-"NULL".

Py_ssize_t PyObject_Size(PyObject *o)
Py_ssize_t PyObject_Length(PyObject *o)
    * Parte del ABI Stabile.*

   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)".

Py_ssize_t PyObject_LengthHint(PyObject *o, Py_ssize_t defaultvalue)

   Return an estimated length for the object *o*. First try to return
   its actual length, then an estimate using "__length_hint__()", and
   finally return the default value. On error return "-1". This is the
   equivalent to the Python expression "operator.length_hint(o,
   defaultvalue)".

   Added in version 3.4.

PyObject *PyObject_GetItem(PyObject *o, PyObject *key)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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)
    * Parte del ABI Stabile.*

   Map the object *key* to the value *v*.  Raise an exception and
   return "-1" on failure; return "0" on success.  This is the
   equivalent of the Python statement "o[key] = v".  This function
   *does not* steal a reference to *v*.

int PyObject_DelItem(PyObject *o, PyObject *key)
    * Parte del ABI Stabile.*

   Remove the mapping for the object *key* from the object *o*.
   Return "-1" on failure.  This is equivalent to the Python statement
   "del o[key]".

PyObject *PyObject_Dir(PyObject *o)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile.*

   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.

PyObject *PyObject_GetAIter(PyObject *o)
    *Valore di ritorno: Nuovo riferimento.** Parte del ABI Stabile
   dalla versione 3.10.*

   This is the equivalent to the Python expression "aiter(o)". Takes
   an "AsyncIterable" object and returns an "AsyncIterator" for it.
   This is typically a new iterator but if the argument is an
   "AsyncIterator", this returns itself. Raises "TypeError" and
   returns "NULL" if the object cannot be iterated.

   Added in version 3.10.

void *PyObject_GetTypeData(PyObject *o, PyTypeObject *cls)
    * Parte del ABI Stabile dalla versione 3.12.*

   Get a pointer to subclass-specific data reserved for *cls*.

   The object *o* must be an instance of *cls*, and *cls* must have
   been created using negative "PyType_Spec.basicsize". Python does
   not check this.

   On error, set an exception and return "NULL".

   Added in version 3.12.

Py_ssize_t PyType_GetTypeDataSize(PyTypeObject *cls)
    * Parte del ABI Stabile dalla versione 3.12.*

   Return the size of the instance memory space reserved for *cls*,
   i.e. the size of the memory "PyObject_GetTypeData()" returns.

   This may be larger than requested using "-PyType_Spec.basicsize";
   it is safe to use this larger size (e.g. with "memset()").

   The type *cls* **must** have been created using negative
   "PyType_Spec.basicsize". Python does not check this.

   On error, set an exception and return a negative value.

   Added in version 3.12.

void *PyObject_GetItemData(PyObject *o)

   Get a pointer to per-item data for a class with
   "Py_TPFLAGS_ITEMS_AT_END".

   On error, set an exception and return "NULL". "TypeError" is raised
   if *o* does not have "Py_TPFLAGS_ITEMS_AT_END" set.

   Added in version 3.12.

int PyObject_VisitManagedDict(PyObject *obj, visitproc visit, void *arg)

   Visit the managed dictionary of *obj*.

   This function must only be called in a traverse function of the
   type which has the "Py_TPFLAGS_MANAGED_DICT" flag set.

   Added in version 3.13.

void PyObject_ClearManagedDict(PyObject *obj)

   Clear the managed dictionary of *obj*.

   This function must only be called in a traverse function of the
   type which has the "Py_TPFLAGS_MANAGED_DICT" flag set.

   Added in version 3.13.
