Object Protocol¶
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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, increment the reference count of NotImplemented and return it).
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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_HasAttr(PyObject *o, PyObject *attr_name)¶ Returns
1if o has the attribute attr_name, and0otherwise. This is equivalent to the Python expressionhasattr(o, attr_name). This function always succeeds.Note that exceptions which occur while calling
__getattr__()and__getattribute__()methods will get suppressed. To get error reporting usePyObject_GetAttr()instead.
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int
PyObject_HasAttrString(PyObject *o, const char *attr_name)¶ Returns
1if o has the attribute attr_name, and0otherwise. This is equivalent to the Python expressionhasattr(o, attr_name). This function always succeeds.Note that exceptions which occur while calling
__getattr__()and__getattribute__()methods and creating a temporary string object will get suppressed. To get error reporting usePyObject_GetAttrString()instead.
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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.
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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.
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PyObject*
PyObject_GenericGetAttr(PyObject *o, PyObject *name)¶ - Return value: New reference.
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)¶ 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, however this feature is deprecated in favour of using
PyObject_DelAttr().
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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. 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, however this feature is deprecated in favour of using
PyObject_DelAttrString().
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int
PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)¶ 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)¶ 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)¶ 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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PyObject*
PyObject_GenericGetDict(PyObject *o, void *context)¶ - Return value: New reference.
A generic implementation for the getter of a
__dict__descriptor. It creates the dictionary if necessary.New in version 3.3.
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int
PyObject_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.
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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, 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, or NULL on failure.
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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, orPy_GE, corresponding to<,<=,==,!=,>, or>=respectively. Returns-1on error,0if the result is false,1otherwise. This is the equivalent of the Python expressiono1 op o2, whereopis 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.
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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 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.
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.
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 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.
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. 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)¶ 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)¶ 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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int
PyCallable_Check(PyObject *o)¶ Determine if the object o is callable. Return
1if the object is callable and0otherwise. This function always succeeds.
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PyObject*
PyObject_Call(PyObject *callable, PyObject *args, PyObject *kwargs)¶ - Return value: New reference.
Call a callable Python object callable, with arguments given by the tuple args, and named arguments given by the dictionary kwargs.
args must not be NULL, use an empty tuple if no arguments are needed. If no named arguments are needed, kwargs can be NULL.
Return the result of the call on success, or raise an exception and return NULL on failure.
This is the equivalent of the Python expression:
callable(*args, **kwargs).
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PyObject*
PyObject_CallObject(PyObject *callable, PyObject *args)¶ - Return value: New reference.
Call a callable Python object callable, with arguments given by the tuple args. If no arguments are needed, then args can be NULL.
Return the result of the call on success, or raise an exception and return NULL on failure.
This is the equivalent of the Python expression:
callable(*args).
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PyObject*
PyObject_CallFunction(PyObject *callable, const 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 can be NULL, indicating that no arguments are provided.Return the result of the call on success, or raise an exception and return 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.Changed in version 3.4: The type of format was changed from
char *.
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PyObject*
PyObject_CallMethod(PyObject *obj, const char *name, const char *format, ...)¶ - Return value: New reference.
Call the method named name of object obj 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 can be NULL, indicating that no arguments are provided.
Return the result of the call on success, or raise an exception and return NULL on failure.
This is the equivalent of the Python expression:
obj.name(arg1, arg2, ...).Note that if you only pass
PyObject *args,PyObject_CallMethodObjArgs()is a faster alternative.Changed in version 3.4: The types of name and format were changed from
char *.
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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.Return the result of the call on success, or raise an exception and return NULL on failure.
This is the equivalent of the Python expression:
callable(arg1, arg2, ...).
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PyObject*
PyObject_CallMethodObjArgs(PyObject *obj, PyObject *name, ..., NULL)¶ - Return value: New reference.
Calls a method of the Python object obj, 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.Return the result of the call on success, or raise an exception and return NULL on failure.
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PyObject*
_PyObject_Vectorcall(PyObject *callable, PyObject *const *args, size_t nargsf, PyObject *kwnames)¶ Call a callable Python object callable, using
vectorcallif possible.args is a C array with the positional arguments.
nargsf is the number of positional arguments plus optionally the flag
PY_VECTORCALL_ARGUMENTS_OFFSET(see below). To get actual number of arguments, usePyVectorcall_NARGS(nargsf).kwnames can be either NULL (no keyword arguments) or a tuple of keyword names. In the latter case, the values of the keyword arguments are stored in args after the positional arguments. The number of keyword arguments does not influence nargsf.
kwnames must contain only objects of type
str(not a subclass), and all keys must be unique.Return the result of the call on success, or raise an exception and return NULL on failure.
This uses the vectorcall protocol if the callable supports it; otherwise, the arguments are converted to use
tp_call.Note
This function is provisional and expected to become public in Python 3.9, with a different name and, possibly, changed semantics. If you use the function, plan for updating your code for Python 3.9.
New in version 3.8.
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PY_VECTORCALL_ARGUMENTS_OFFSET¶ If set in a vectorcall nargsf argument, the callee is allowed to temporarily change
args[-1]. In other words, args points to argument 1 (not 0) in the allocated vector. The callee must restore the value ofargs[-1]before returning.Whenever they can do so cheaply (without additional allocation), callers are encouraged to use
PY_VECTORCALL_ARGUMENTS_OFFSET. Doing so will allow callables such as bound methods to make their onward calls (which include a prepended self argument) cheaply.New in version 3.8.
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Py_ssize_t
PyVectorcall_NARGS(size_t nargsf)¶ Given a vectorcall nargsf argument, return the actual number of arguments. Currently equivalent to
nargsf & ~PY_VECTORCALL_ARGUMENTS_OFFSET.New in version 3.8.
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PyObject*
_PyObject_FastCallDict(PyObject *callable, PyObject *const *args, size_t nargsf, PyObject *kwdict)¶ Same as
_PyObject_Vectorcall()except that the keyword arguments are passed as a dictionary in kwdict. This may be NULL if there are no keyword arguments.For callables supporting
vectorcall, the arguments are internally converted to the vectorcall convention. Therefore, this function adds some overhead compared to_PyObject_Vectorcall(). It should only be used if the caller already has a dictionary ready to use.Note
This function is provisional and expected to become public in Python 3.9, with a different name and, possibly, changed semantics. If you use the function, plan for updating your code for Python 3.9.
New in version 3.8.
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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 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)¶ 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)¶ 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)¶ 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.
When o is non-NULL, returns a type object corresponding to the object type of object o. On failure, raises
SystemErrorand returns NULL. This is equivalent to the Python expressiontype(o). This function increments the reference count of the return value. There’s really no reason to use this function instead of the common expressiono->ob_type, which returns a pointer of typePyTypeObject*, except when the incremented reference count is needed.
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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.
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Py_ssize_t
PyObject_Size(PyObject *o)¶ -
Py_ssize_t
PyObject_Length(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,
-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 default)¶ 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, default).New in version 3.4.
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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].
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int
PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)¶ 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.
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int
PyObject_DelItem(PyObject *o, PyObject *key)¶ 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.
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 Pythondir(), returning the names of the current locals; in this case, if no execution frame is active then NULL is returned butPyErr_Occurred()will return false.
