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72 lines
2.5 KiB
ReStructuredText
72 lines
2.5 KiB
ReStructuredText
.. highlightlang:: c
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.. _allocating-objects:
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Allocating Objects on the Heap
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==============================
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.. c:function:: PyObject* _PyObject_New(PyTypeObject *type)
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.. c:function:: PyVarObject* _PyObject_NewVar(PyTypeObject *type, Py_ssize_t size)
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.. c:function:: PyObject* PyObject_Init(PyObject *op, PyTypeObject *type)
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Initialize a newly-allocated object *op* with its type and initial
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reference. Returns the initialized object. If *type* indicates that the
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object participates in the cyclic garbage detector, it is added to the
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detector's set of observed objects. Other fields of the object are not
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affected.
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.. c:function:: PyVarObject* PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)
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This does everything :c:func:`PyObject_Init` does, and also initializes the
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length information for a variable-size object.
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.. c:function:: TYPE* PyObject_New(TYPE, PyTypeObject *type)
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Allocate a new Python object using the C structure type *TYPE* and the
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Python type object *type*. Fields not defined by the Python object header
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are not initialized; the object's reference count will be one. The size of
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the memory allocation is determined from the :attr:`tp_basicsize` field of
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the type object.
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.. c:function:: TYPE* PyObject_NewVar(TYPE, PyTypeObject *type, Py_ssize_t size)
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Allocate a new Python object using the C structure type *TYPE* and the
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Python type object *type*. Fields not defined by the Python object header
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are not initialized. The allocated memory allows for the *TYPE* structure
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plus *size* fields of the size given by the :attr:`tp_itemsize` field of
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*type*. This is useful for implementing objects like tuples, which are
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able to determine their size at construction time. Embedding the array of
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fields into the same allocation decreases the number of allocations,
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improving the memory management efficiency.
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.. c:function:: void PyObject_Del(PyObject *op)
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Releases memory allocated to an object using :c:func:`PyObject_New` or
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:c:func:`PyObject_NewVar`. This is normally called from the
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:attr:`tp_dealloc` handler specified in the object's type. The fields of
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the object should not be accessed after this call as the memory is no
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longer a valid Python object.
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.. c:var:: PyObject _Py_NoneStruct
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Object which is visible in Python as ``None``. This should only be accessed
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using the :c:macro:`Py_None` macro, which evaluates to a pointer to this
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object.
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.. seealso::
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:c:func:`PyModule_Create`
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To allocate and create extension modules.
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