Python/C API Reference Manual
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10.1 Allocating Objects on the Heap

PyObject* _PyObject_New(PyTypeObject *type)

Return value: New reference.

PyVarObject* _PyObject_NewVar(PyTypeObject *type, int size)

Return value: New reference.

void _PyObject_Del(PyObject *op)

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

Return value: Borrowed reference.

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 it added to the detector's set of observed objects. Other fields of the object are not affected.

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

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

TYPE* PyObject_New(TYPE, PyTypeObject *type)

Return value: New reference.

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, int size)

Return value: New reference.

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(PyObject *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.

TYPE* PyObject_NEW(TYPE, PyTypeObject *type)

Return value: New reference.

Macro version of PyObject_New(), to gain performance at the expense of safety. This does not check type for a NULL value.

TYPE* PyObject_NEW_VAR(TYPE, PyTypeObject *type, int size)

Return value: New reference.

Macro version of PyObject_NewVar(), to gain performance at the expense of safety. This does not check type for a NULL value.

void PyObject_DEL(PyObject *op)

Macro version of PyObject_Del().

PyObject* Py_InitModule(char *name, PyMethodDef *methods)

Return value: Borrowed reference.

Create a new module object based on a name and table of functions, returning the new module object.

PyObject* Py_InitModule3(char *name, PyMethodDef *methods, char *doc)

Return value: Borrowed reference.

Create a new module object based on a name and table of functions, returning the new module object. If doc is non-NULL, it will be used to define the docstring for the module.

PyObject* Py_InitModule4(char *name, PyMethodDef *methods, char *doc, PyObject *self, int apiver)

Return value: Borrowed reference.

Create a new module object based on a name and table of functions, returning the new module object. If doc is non-NULL, it will be used to define the docstring for the module. If self is non-NULL, it will passed to the functions of the module as their (otherwise NULL) first parameter. (This was added as an experimental feature, and there are no known uses in the current version of Python.) For apiver, the only value which should be passed is defined by the constant PYTHON_API_VERSION.

Note: Most uses of this function should probably be using the Py_InitModule3() instead; only use this if you are sure you need it.

DL_IMPORT

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.