1.. highlight:: c 2 3.. _allocating-objects: 4 5Allocating Objects on the Heap 6============================== 7 8 9.. c:function:: PyObject* _PyObject_New(PyTypeObject *type) 10 11 12.. c:function:: PyVarObject* _PyObject_NewVar(PyTypeObject *type, Py_ssize_t size) 13 14 15.. c:function:: PyObject* PyObject_Init(PyObject *op, PyTypeObject *type) 16 17 Initialize a newly-allocated object *op* with its type and initial 18 reference. Returns the initialized object. If *type* indicates that the 19 object participates in the cyclic garbage detector, it is added to the 20 detector's set of observed objects. Other fields of the object are not 21 affected. 22 23 24.. c:function:: PyVarObject* PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size) 25 26 This does everything :c:func:`PyObject_Init` does, and also initializes the 27 length information for a variable-size object. 28 29 30.. c:function:: TYPE* PyObject_New(TYPE, PyTypeObject *type) 31 32 Allocate a new Python object using the C structure type *TYPE* and the 33 Python type object *type*. Fields not defined by the Python object header 34 are not initialized; the object's reference count will be one. The size of 35 the memory allocation is determined from the :c:member:`~PyTypeObject.tp_basicsize` field of 36 the type object. 37 38 39.. c:function:: TYPE* PyObject_NewVar(TYPE, PyTypeObject *type, Py_ssize_t size) 40 41 Allocate a new Python object using the C structure type *TYPE* and the 42 Python type object *type*. Fields not defined by the Python object header 43 are not initialized. The allocated memory allows for the *TYPE* structure 44 plus *size* fields of the size given by the :c:member:`~PyTypeObject.tp_itemsize` field of 45 *type*. This is useful for implementing objects like tuples, which are 46 able to determine their size at construction time. Embedding the array of 47 fields into the same allocation decreases the number of allocations, 48 improving the memory management efficiency. 49 50 51.. c:function:: void PyObject_Del(void *op) 52 53 Releases memory allocated to an object using :c:func:`PyObject_New` or 54 :c:func:`PyObject_NewVar`. This is normally called from the 55 :c:member:`~PyTypeObject.tp_dealloc` handler specified in the object's type. The fields of 56 the object should not be accessed after this call as the memory is no 57 longer a valid Python object. 58 59 60.. c:var:: PyObject _Py_NoneStruct 61 62 Object which is visible in Python as ``None``. This should only be accessed 63 using the :c:macro:`Py_None` macro, which evaluates to a pointer to this 64 object. 65 66 67.. seealso:: 68 69 :c:func:`PyModule_Create` 70 To allocate and create extension modules. 71 72