Object Protocol¶
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PyObject *Py_GetConstant(unsigned int constant_id)¶
- Part of the Stable ABI since version 3.13.
Get a strong reference to a constant.
Set an exception and return
NULLif constant_id is invalid.constant_id must be one of these constant identifiers:
Constant Identifier
Value
Returned object
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Py_CONSTANT_NONE¶
0-
Py_CONSTANT_FALSE¶
1-
Py_CONSTANT_TRUE¶
2-
Py_CONSTANT_ELLIPSIS¶
3-
Py_CONSTANT_NOT_IMPLEMENTED¶
4-
Py_CONSTANT_ZERO¶
50-
Py_CONSTANT_ONE¶
61-
Py_CONSTANT_EMPTY_STR¶
7''-
Py_CONSTANT_EMPTY_BYTES¶
8b''-
Py_CONSTANT_EMPTY_TUPLE¶
9()Numeric values are only given for projects which cannot use the constant identifiers.
Added in version 3.13.
CPython implementation detail: In CPython, all of these constants are immortal.
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Py_CONSTANT_NONE¶
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PyObject *Py_GetConstantBorrowed(unsigned int constant_id)¶
- Part of the Stable ABI since version 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.
Added in version 3.13.
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PyObject *Py_NotImplemented¶
The
NotImplementedsingleton, used to signal that an operation is not implemented for the given type combination.
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Py_RETURN_NOTIMPLEMENTED¶
Properly handle returning
Py_NotImplementedfrom within a C function (that is, create a new strong reference toNotImplementedand return it).
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Py_PRINT_RAW¶
Flag to be used with multiple functions that print the object (like
PyObject_Print()andPyFile_WriteObject()). If passed, these function would use thestr()of the object instead of therepr().
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int PyObject_Print(PyObject *o, FILE *fp, int flags)¶
Print an object o, on file fp. Returns
-1on error. The flags argument is used to enable certain printing options. The only option currently supported isPy_PRINT_RAW; if given, thestr()of the object is written instead of therepr().
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int PyObject_HasAttrWithError(PyObject *o, PyObject *attr_name)¶
- Part of the Stable ABI since version 3.13.
Returns
1if o has the attribute attr_name, and0otherwise. This is equivalent to the Python expressionhasattr(o, attr_name). On failure, return-1.Added in version 3.13.
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int PyObject_HasAttrStringWithError(PyObject *o, const char *attr_name)¶
- Part of the Stable ABI since version 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.
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int PyObject_HasAttr(PyObject *o, PyObject *attr_name)¶
- Part of the Stable ABI.
Returns
1if o has the attribute attr_name, and0otherwise. This function always succeeds.Note
Exceptions that occur when this calls
__getattr__()and__getattribute__()methods are silently ignored. For proper error handling, usePyObject_HasAttrWithError(),PyObject_GetOptionalAttr()orPyObject_GetAttr()instead.
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int PyObject_HasAttrString(PyObject *o, const char *attr_name)¶
- Part of the Stable ABI.
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*.Note
Exceptions that occur when this calls
__getattr__()and__getattribute__()methods or while creating the temporarystrobject are silently ignored. For proper error handling, usePyObject_HasAttrStringWithError(),PyObject_GetOptionalAttrString()orPyObject_GetAttrString()instead.
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PyObject *PyObject_GetAttr(PyObject *o, PyObject *attr_name)¶
- Return value: New reference. Part of the Stable ABI.
Retrieve an attribute named attr_name from object o. Returns the attribute value on success, or
NULLon failure. This is the equivalent of the Python expressiono.attr_name.If the missing attribute should not be treated as a failure, you can use
PyObject_GetOptionalAttr()instead.
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PyObject *PyObject_GetAttrString(PyObject *o, const char *attr_name)¶
- Return value: New reference. Part of the Stable ABI.
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.
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int PyObject_GetOptionalAttr(PyObject *obj, PyObject *attr_name, PyObject **result);¶
- Part of the Stable ABI since version 3.13.
Variant of
PyObject_GetAttr()which doesn’t raiseAttributeErrorif the attribute is not found.If the attribute is found, return
1and set *result to a new strong reference to the attribute. If the attribute is not found, return0and set *result toNULL; theAttributeErroris silenced. If an error other thanAttributeErroris raised, return-1and set *result toNULL.Added in version 3.13.
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int PyObject_GetOptionalAttrString(PyObject *obj, const char *attr_name, PyObject **result);¶
- Part of the Stable ABI since version 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.
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PyObject *PyObject_GenericGetAttr(PyObject *o, PyObject *name)¶
- Return value: New reference. Part of the Stable ABI.
Generic attribute getter function that is meant to be put into a type object’s
tp_getattroslot. 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, anAttributeErroris raised.
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int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v)¶
- Part of the Stable ABI.
Set the value of the attribute named attr_name, for object o, to the value v. Raise an exception and return
-1on failure; return0on success. This is the equivalent of the Python statemento.attr_name = v.If v is
NULL, the attribute is deleted. This behaviour is deprecated in favour of usingPyObject_DelAttr(), but there are currently no plans to remove it.
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int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)¶
- Part of the Stable ABI.
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 usingPyObject_DelAttrString().The number of different attribute names passed to this function should be kept small, usually by using a statically allocated string as attr_name. For attribute names that aren’t known at compile time, prefer calling
PyUnicode_FromString()andPyObject_SetAttr()directly. For more details, seePyUnicode_InternFromString(), which may be used internally to create a key object.
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int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)¶
- Part of the Stable ABI.
Generic attribute setter and deleter function that is meant to be put into a type object’s
tp_setattroslot. 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,0is returned, otherwise anAttributeErroris raised and-1is returned.
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int PyObject_DelAttr(PyObject *o, PyObject *attr_name)¶
- Part of the Stable ABI since version 3.13.
Delete attribute named attr_name, for object o. Returns
-1on failure. This is the equivalent of the Python statementdel o.attr_name.
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int PyObject_DelAttrString(PyObject *o, const char *attr_name)¶
- Part of the Stable ABI since version 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*.The number of different attribute names passed to this function should be kept small, usually by using a statically allocated string as attr_name. For attribute names that aren’t known at compile time, prefer calling
PyUnicode_FromString()andPyObject_DelAttr()directly. For more details, seePyUnicode_InternFromString(), which may be used internally to create a key object for lookup.
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PyObject *PyObject_GenericGetDict(PyObject *o, void *context)¶
- Return value: New reference. Part of the Stable ABI since version 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. PassNULLfor context when calling it. Since this function may need to allocate memory for the dictionary, it may be more efficient to callPyObject_GetAttr()when accessing an attribute on the object.On failure, returns
NULLwith an exception set.Added in version 3.3.
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int PyObject_GenericSetDict(PyObject *o, PyObject *value, void *context)¶
- Part of the Stable ABI since version 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.
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PyObject **_PyObject_GetDictPtr(PyObject *obj)¶
Return a pointer to
__dict__of the object obj. If there is no__dict__, returnNULLwithout 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.
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PyObject *PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)¶
- Return value: New reference. Part of the Stable ABI.
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, orPy_GE, corresponding to<,<=,==,!=,>, or>=respectively. This is the equivalent of the Python expressiono1 op o2, whereopis the operator corresponding to opid. Returns the value of the comparison on success, orNULLon failure.
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int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid)¶
- Part of the Stable ABI.
Compare the values of o1 and o2 using the operation specified by opid, like
PyObject_RichCompare(), but returns-1on error,0if the result is false,1otherwise.
Note
If o1 and o2 are the same object, PyObject_RichCompareBool()
will always return 1 for Py_EQ and 0 for Py_NE.
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PyObject *PyObject_Format(PyObject *obj, PyObject *format_spec)¶
- Part of the Stable ABI.
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 toformat(obj). Returns the formatted string on success,NULLon failure.
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PyObject *PyObject_Repr(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
Compute a string representation of object o. Returns the string representation on success,
NULLon failure. This is the equivalent of the Python expressionrepr(o). Called by therepr()built-in function.Changed in version 3.4: This function now includes a debug assertion to help ensure that it does not silently discard an active exception.
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PyObject *PyObject_ASCII(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
As
PyObject_Repr(), compute a string representation of object o, but escape the non-ASCII characters in the string returned byPyObject_Repr()with\x,\uor\Uescapes. This generates a string similar to that returned byPyObject_Repr()in Python 2. Called by theascii()built-in function.
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PyObject *PyObject_Str(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
Compute a string representation of object o. Returns the string representation on success,
NULLon failure. This is the equivalent of the Python expressionstr(o). Called by thestr()built-in function and, therefore, by theprint()function.Changed in version 3.4: This function now includes a debug assertion to help ensure that it does not silently discard an active exception.
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PyObject *PyObject_Bytes(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
Compute a bytes representation of object o.
NULLis returned on failure and a bytes object on success. This is equivalent to the Python expressionbytes(o), when o is not an integer. Unlikebytes(o), a TypeError is raised when o is an integer instead of a zero-initialized bytes object.
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int PyObject_IsSubclass(PyObject *derived, PyObject *cls)¶
- Part of the Stable ABI.
Return
1if the class derived is identical to or derived from the class cls, otherwise return0. 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
1when at least one of the checks returns1, otherwise it will be0.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 incls.__mro__.Normally only class objects, i.e. instances of
typeor a derived class, are considered classes. However, objects can override this by having a__bases__attribute (which must be a tuple of base classes).
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int PyObject_IsInstance(PyObject *inst, PyObject *cls)¶
- Part of the Stable ABI.
Return
1if inst is an instance of the class cls or a subclass of cls, or0if not. On error, returns-1and sets an exception.If cls is a tuple, the check will be done against every entry in cls. The result will be
1when at least one of the checks returns1, otherwise it will be0.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).
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Py_hash_t PyObject_Hash(PyObject *o)¶
- Part of the Stable ABI.
Compute and return the hash value of an object o. On failure, return
-1. This is the equivalent of the Python expressionhash(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.
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Py_hash_t PyObject_HashNotImplemented(PyObject *o)¶
- Part of the Stable ABI.
Set a
TypeErrorindicating thattype(o)is not hashable and return-1. This function receives special treatment when stored in atp_hashslot, allowing a type to explicitly indicate to the interpreter that it is not hashable.
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int PyObject_IsTrue(PyObject *o)¶
- Part of the Stable ABI.
Returns
1if the object o is considered to be true, and0otherwise. This is equivalent to the Python expressionnot not o. On failure, return-1.
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int PyObject_Not(PyObject *o)¶
- Part of the Stable ABI.
Returns
0if the object o is considered to be true, and1otherwise. This is equivalent to the Python expressionnot o. On failure, return-1.
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PyObject *PyObject_Type(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
When o is non-
NULL, returns a type object corresponding to the object type of object o. On failure, raisesSystemErrorand returnsNULL. This is equivalent to the Python expressiontype(o). This function creates a new strong reference to the return value. There’s really no reason to use this function instead of thePy_TYPE()function, which returns a pointer of type PyTypeObject*, except when a new strong reference is needed.
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int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)¶
Return non-zero if the object o is of type type or a subtype of type, and
0otherwise. Both parameters must be non-NULL.
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Py_ssize_t PyObject_Size(PyObject *o)¶
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Py_ssize_t PyObject_Length(PyObject *o)¶
- Part of the Stable ABI.
Return the length of object o. If the object o provides either the sequence and mapping protocols, the sequence length is returned. On error,
-1is returned. This is the equivalent to the Python expressionlen(o).
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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 expressionoperator.length_hint(o, defaultvalue).Added in version 3.4.
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PyObject *PyObject_GetItem(PyObject *o, PyObject *key)¶
- Return value: New reference. Part of the Stable ABI.
Return element of o corresponding to the object key or
NULLon failure. This is the equivalent of the Python expressiono[key].
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int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)¶
- Part of the Stable ABI.
Map the object key to the value v. Raise an exception and return
-1on failure; return0on success. This is the equivalent of the Python statemento[key] = v. This function does not steal a reference to v.
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int PyObject_DelItem(PyObject *o, PyObject *key)¶
- Part of the Stable ABI.
Remove the mapping for the object key from the object o. Return
-1on failure. This is equivalent to the Python statementdel o[key].
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PyObject *PyObject_Dir(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
This is equivalent to the Python expression
dir(o), returning a (possibly empty) list of strings appropriate for the object argument, orNULLif there was an error. If the argument isNULL, this is like the Pythondir(), returning the names of the current locals; in this case, if no execution frame is active thenNULLis returned butPyErr_Occurred()will return false.
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PyObject *PyObject_GetIter(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI.
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. RaisesTypeErrorand returnsNULLif the object cannot be iterated.
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PyObject *PyObject_GetAIter(PyObject *o)¶
- Return value: New reference. Part of the Stable ABI since version 3.10.
This is the equivalent to the Python expression
aiter(o). Takes anAsyncIterableobject and returns anAsyncIteratorfor it. This is typically a new iterator but if the argument is anAsyncIterator, this returns itself. RaisesTypeErrorand returnsNULLif the object cannot be iterated.Added in version 3.10.
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void *PyObject_GetTypeData(PyObject *o, PyTypeObject *cls)¶
- Part of the Stable ABI since version 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.
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Py_ssize_t PyType_GetTypeDataSize(PyTypeObject *cls)¶
- Part of the Stable ABI since version 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. withmemset()).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.
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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.TypeErroris raised if o does not havePy_TPFLAGS_ITEMS_AT_ENDset.Added in version 3.12.
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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_DICTflag set.Added in version 3.13.
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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_DICTflag set.Added in version 3.13.