堆栈 源码

 

 

/* Object and type object interface */

/*

Objects are structures allocated on the heap. Special rules apply to

the use of objects to ensure they are properly garbage-collected.

Objects are never allocated statically or on the stack; they must be

accessed through special macros and functions only. (Type objects are

exceptions to the first rule; the standard types are represented by

statically initialized type objects, although work on type/class unification

for Python 2.2 made it possible to have heap-allocated type objects too).

An object has a 'reference count' that is increased or decreased when a

pointer to the object is copied or deleted; when the reference count

reaches zero there are no references to the object left and it can be

removed from the heap.

An object has a 'type' that determines what it represents and what kind

of data it contains. An object's type is fixed when it is created.

Types themselves are represented as objects; an object contains a

pointer to the corresponding type object. The type itself has a type

pointer pointing to the object representing the type 'type', which

contains a pointer to itself!).

Objects do not float around in memory; once allocated an object keeps

the same size and address. Objects that must hold variable-size data

can contain pointers to variable-size parts of the object. Not all

objects of the same type have the same size; but the size cannot change

after allocation. (These restrictions are made so a reference to an

object can be simply a pointer -- moving an object would require

updating all the pointers, and changing an object's size would require

moving it if there was another object right next to it.)

Objects are always accessed through pointers of the type 'PyObject *'.

The type 'PyObject' is a structure that only contains the reference count

and the type pointer. The actual memory allocated for an object

contains other data that can only be accessed after casting the pointer

to a pointer to a longer structure type. This longer type must start

with the reference count and type fields; the macro PyObject_HEAD should be

used for this (to accommodate for future changes). The implementation

of a particular object type can cast the object pointer to the proper

type and back.

A standard interface exists for objects that contain an array of items

whose size is determined when the object is allocated.

*/

 

 

 

Python-3.7.4\Include\object.h

 

在Python中，对象就是为C中的结构体在堆上申请的一块内存。