Allocating Objects on the Heap — Python 3.13.14 documentation
Description: Deprecated aliases: These are soft deprecated aliases to existing functions and macros. They exist solely for backwards compatibility.,, Deprecated alias, Function,,,, PyObject_New,,, PyObject_NewV...

# 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.

PyObject *PyObject_Init(PyObject *op, PyTypeObject *type)
  Return value: Borrowed reference. Part of the Stable ABI.

  Initialize a newly allocated object op with its type and initial reference. Returns the initialized object. Other fields of the object are not affected.

PyVarObject *PyObject_InitVar(PyVarObject *op, PyTypeObject *type, Py_ssize_t size)
  Return value: Borrowed reference. Part of the Stable ABI.

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

PyObject_New(TYPE, typeobj)

  Allocate a new Python object using the C structure type TYPE and the Python type object typeobj (`PyTypeObject*`). Fields not defined by the Python object header are not initialized. The caller will own the only reference to the object (i.e. its reference count will be one). The size of the memory allocation is determined from the `tp_basicsize` field of the type object.

  Note that this function is unsuitable if typeobj has `Py_TPFLAGS_HAVE_GC` set. For such objects, use `PyObject_GC_New()` instead.

PyObject_NewVar(TYPE, typeobj, size)

  Allocate a new Python object using the C structure type TYPE and the Python type object typeobj (`PyTypeObject*`). Fields not defined by the Python object header are not initialized. The allocated memory allows for the TYPE structure plus size (`Py_ssize_t`) fields of the size given by the `tp_itemsize` field of typeobj. 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.

  Note that this function is unsuitable if typeobj has `Py_TPFLAGS_HAVE_GC` set. For such objects, use `PyObject_GC_NewVar()` instead.

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.

See also

Module Objects

  To allocate and create extension modules.

## Deprecated aliases

These are soft deprecated aliases to existing functions and macros. They exist solely for backwards compatibility.

Deprecated alias | Function
--- | ---
PyObject_NEW(type, typeobj) | `PyObject_New`
PyObject_NEW_VAR(type, typeobj, n) | `PyObject_NewVar`
PyObject_INIT(op, typeobj) | `PyObject_Init()`
PyObject_INIT_VAR(op, typeobj, n) | `PyObject_InitVar()`
PyObject_MALLOC(n) | `PyObject_Malloc()`
PyObject_REALLOC(p, n) | `PyObject_Realloc()`
PyObject_FREE(p) | `PyObject_Free()`
PyObject_DEL(p) | `PyObject_Free()`
PyObject_Del(p) | `PyObject_Free()`