Python中的List对象(Python 源码剖析第四章)

 1 typedef struct {

 2     PyObject_VAR_HEAD

 3     /* Vector of pointers to list elements.  list[0] is ob_item[0], etc. */

 4     PyObject **ob_item;

 5 

 6     /* ob_item contains space for 'allocated' elements.  The number

 7      * currently in use is ob_size.

 8      * Invariants:

 9      *     0 <= ob_size <= allocated

      *     len(list) == ob_size

      *     ob_item == NULL implies ob_size == allocated == 0

      * list.sort() temporarily sets allocated to -1 to detect mutations.

      *

      * Items must normally not be NULL, except during construction when

      * the list is not yet visible outside the function that builds it.

      */

     Py_ssize_t allocated;

 } PyListObject;