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  

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来源： https://www.cnblogs.com/yuanjiangw/p/11574106.html