Allocating Objects on the Heap — Python 2.7.18 documentation

This document is for an old version of Python that is no longer supported. You should upgrade and read the Python documentation for the current stable release.

# Allocating Objects on the Heap

PyObject* `_PyObject_New`(PyTypeObject *type)
  Return value: New reference.

PyVarObject* `_PyObject_NewVar`(PyTypeObject *type, Py_ssize_t size)
  Return value: New reference.

  Changed in version 2.5: This function used an `int` type for size. This might require changes in your code for properly supporting 64-bit systems.

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

PyVarObject* `PyObject_InitVar`(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)
  Return value: Borrowed reference.

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

  Changed in version 2.5: This function used an `int` type for size. This might require changes in your code for properly supporting 64-bit systems.

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, Py_ssize_t 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.

  Changed in version 2.5: This function used an `int` type for size. This might require changes in your code for properly supporting 64-bit systems.

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.

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.

  Changed in version 2.3: Older versions of Python did not support NULL as the value for the methods argument.

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.

  Changed in version 2.3: Older versions of Python did not support NULL as the value for the methods argument.

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 be 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.

  Changed in version 2.3: Older versions of Python did not support NULL as the value for the methods argument.

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.