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.. highlightlang:: c
.. _allocating-objects:
Allocating Objects on the Heap
==============================
.. cfunction:: PyObject* _PyObject_New(PyTypeObject *type)
.. cfunction:: PyVarObject* _PyObject_NewVar(PyTypeObject *type, Py_ssize_t size)
.. cfunction:: 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.
.. cfunction:: PyVarObject* PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)
This does everything :cfunc:`PyObject_Init` does, and also initializes the
length information for a variable-size object.
.. cfunction:: 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 :attr:`tp_basicsize` field of the type object.
.. cfunction:: 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 :attr:`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.
.. cfunction:: void PyObject_Del(PyObject *op)
Releases memory allocated to an object using :cfunc:`PyObject_New` or
:cfunc:`PyObject_NewVar`. This is normally called from the :attr:`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.
.. cvar:: PyObject _Py_NoneStruct
Object which is visible in Python as ``None``. This should only be accessed
using the :cmacro:`Py_None` macro, which evaluates to a pointer to this
object.
.. seealso::
:cfunc:`PyModule_Create`
To allocate and create extension modules.
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