Allocating Objects on the Heap — Python documentation

Allocating Objects on the Heap

PyObject *_PyObject_New(PyTypeObject *type)

PyVarObject *_PyObject_NewVar(PyTypeObject *type, Py_ssize_t size)

PyObject *PyObject_Init(PyObject *op, PyTypeObject *type)

Initialize a newly-allocated object op with its type and initial reference. Returns the initialized object. If type indicates that the object participates in the cyclic garbage detector, it is added to the detector’s set of observed objects. Other fields of the object are not affected.

PyVarObject *PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)

This does everything PyObject_Init() does, and also initializes the length information for a variable-size object.

TYPE *PyObject_New(TYPE, PyTypeObject *type)

Allocate a new Python object using the C structure type TYPE and the Python type object type. Fields not defined by the Python object header are not initialized; the object’s reference count will be one. The size of the memory allocation is determined from the tp_basicsize field of the type object.

TYPE *PyObject_NewVar(TYPE, PyTypeObject *type, Py_ssize_t size)

Allocate a new Python object using the C structure type TYPE and the Python type object type. Fields not defined by the Python object header are not initialized. The allocated memory allows for the TYPE structure plus size fields of the size given by the tp_itemsize field of type. This is useful for implementing objects like tuples, which are able to determine their size at construction time. Embedding the array of fields into the same allocation decreases the number of allocations, improving the memory management efficiency.

void PyObject_Del(void *op)

Releases memory allocated to an object using PyObject_New() or PyObject_NewVar(). This is normally called from the tp_dealloc handler specified in the object’s type. The fields of the object should not be accessed after this call as the memory is no longer a valid Python object.

PyObject _Py_NoneStruct

Object which is visible in Python as None. This should only be accessed using the Py_None macro, which evaluates to a pointer to this object.

See also

PyModule_Create()

To allocate and create extension modules.