Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Tip revision: f5caf2b30bfe70e5107f816c9e7f7fe3ef5299d9 authored by Larry Hastings on 25 February 2015, 12:15:33 UTC
Checking in this change LOCAL ONLY NO UPLOAD ANYWHERE
Checking in this change LOCAL ONLY NO UPLOAD ANYWHERE
Tip revision: f5caf2b
allocation.rst
.. highlightlang:: c
.. _allocating-objects:
Allocating Objects on the Heap
==============================
.. c:function:: PyObject* _PyObject_New(PyTypeObject *type)
.. c:function:: PyVarObject* _PyObject_NewVar(PyTypeObject *type, Py_ssize_t size)
.. c:function:: 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.
.. c:function:: PyVarObject* PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)
This does everything :c:func:`PyObject_Init` does, and also initializes the
length information for a variable-size object.
.. c:function:: 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 :c:member:`~PyTypeObject.tp_basicsize` field of
the type object.
.. c:function:: 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 :c:member:`~PyTypeObject.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.
.. c:function:: void PyObject_Del(PyObject *op)
Releases memory allocated to an object using :c:func:`PyObject_New` or
:c:func:`PyObject_NewVar`. This is normally called from the
:c:member:`~PyTypeObject.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.
.. c:var:: PyObject _Py_NoneStruct
Object which is visible in Python as ``None``. This should only be accessed
using the :c:macro:`Py_None` macro, which evaluates to a pointer to this
object.
.. seealso::
:c:func:`PyModule_Create`
To allocate and create extension modules.