Type Objects¶
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PyTypeObject¶
- The C structure of the objects used to describe built-in types. 
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PyObject* PyType_Type¶
- This is the type object for type objects; it is the same object as - typein the Python layer.
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int PyType_Check(PyObject *o)¶
- Return true if the object o is a type object, including instances of types derived from the standard type object. Return false in all other cases. 
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int PyType_CheckExact(PyObject *o)¶
- Return true if the object o is a type object, but not a subtype of the standard type object. Return false in all other cases. 
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unsigned int PyType_ClearCache()¶
- Clear the internal lookup cache. Return the current version tag. 
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unsigned long PyType_GetFlags(PyTypeObject* type)¶
- Return the - tp_flagsmember of type. This function is primarily meant for use with Py_LIMITED_API; the individual flag bits are guaranteed to be stable across Python releases, but access to- tp_flagsitself is not part of the limited API.- New in version 3.2. - Changed in version 3.4: The return type is now - unsigned longrather than- long.
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void PyType_Modified(PyTypeObject *type)¶
- Invalidate the internal lookup cache for the type and all of its subtypes. This function must be called after any manual modification of the attributes or base classes of the type. 
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int PyType_HasFeature(PyTypeObject *o, int feature)¶
- Return true if the type object o sets the feature feature. Type features are denoted by single bit flags. 
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int PyType_IS_GC(PyTypeObject *o)¶
- Return true if the type object includes support for the cycle detector; this tests the type flag - Py_TPFLAGS_HAVE_GC.
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int PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)¶
- Return true if a is a subtype of b. - This function only checks for actual subtypes, which means that - __subclasscheck__()is not called on b. Call- PyObject_IsSubclass()to do the same check that- issubclass()would do.
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PyObject* PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)¶
- Return value: New reference.Generic handler for the tp_allocslot of a type object. Use Python’s default memory allocation mechanism to allocate a new instance and initialize all its contents toNULL.
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PyObject* PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)¶
- Return value: New reference.Generic handler for the tp_newslot of a type object. Create a new instance using the type’stp_allocslot.
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int PyType_Ready(PyTypeObject *type)¶
- Finalize a type object. This should be called on all type objects to finish their initialization. This function is responsible for adding inherited slots from a type’s base class. Return - 0on success, or return- -1and sets an exception on error.
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void* PyType_GetSlot(PyTypeObject *type, int slot)¶
- Return the function pointer stored in the given slot. If the result is - NULL, this indicates that either the slot is- NULL, or that the function was called with invalid parameters. Callers will typically cast the result pointer into the appropriate function type.- See - PyType_Slot.slotfor possible values of the slot argument.- An exception is raised if type is not a heap type. - New in version 3.4. 
Creating Heap-Allocated Types¶
The following functions and structs are used to create heap types.
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PyObject* PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases)¶
- Return value: New reference.Creates and returns a heap type object from the spec ( Py_TPFLAGS_HEAPTYPE).If bases is a tuple, the created heap type contains all types contained in it as base types. If bases is NULL, the Py_tp_bases slot is used instead. If that also isNULL, the Py_tp_base slot is used instead. If that also isNULL, the new type derives fromobject.This function calls PyType_Ready()on the new type.New in version 3.3. 
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PyObject* PyType_FromSpec(PyType_Spec *spec)¶
- Return value: New reference.Equivalent to PyType_FromSpecWithBases(spec, NULL).
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PyType_Spec¶
- Structure defining a type’s behavior. - 
const char* PyType_Spec.name¶
- Name of the type, used to set - PyTypeObject.tp_name.
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int PyType_Spec.basicsize¶
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int PyType_Spec.itemsize¶
- Size of the instance in bytes, used to set - PyTypeObject.tp_basicsizeand- PyTypeObject.tp_itemsize.
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int PyType_Spec.flags¶
- Type flags, used to set - PyTypeObject.tp_flags.- If the - Py_TPFLAGS_HEAPTYPEflag is not set,- PyType_FromSpecWithBases()sets it automatically.
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PyType_Slot *PyType_Spec.slots¶
- Array of - PyType_Slotstructures. Terminated by the special slot value- {0, NULL}.
 
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const char* 
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PyType_Slot¶
- Structure defining optional functionality of a type, containing a slot ID and a value pointer. - 
int PyType_Slot.slot¶
- A slot ID. - Slot IDs are named like the field names of the structures - PyTypeObject,- PyNumberMethods,- PySequenceMethods,- PyMappingMethodsand- PyAsyncMethodswith an added- Py_prefix. For example, use:- Py_tp_deallocto set- PyTypeObject.tp_dealloc
- Py_nb_addto set- PyNumberMethods.nb_add
- Py_sq_lengthto set- PySequenceMethods.sq_length
 - The following fields cannot be set using - PyType_Specand- PyType_Slot:
- tp_print
 - Setting - Py_tp_basesor- Py_tp_basemay be problematic on some platforms. To avoid issues, use the bases argument of- PyType_FromSpecWithBases()instead.
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void *PyType_Slot.pfunc¶
- The desired value of the slot. In most cases, this is a pointer to a function. - May not be - NULL.
 
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