三、对象到底如何创建

来源：互联网发布：80端口提供什么服务编辑：程序博客网时间：2024/06/07 22:33

http://blog.csdn.net/debugm/article/details/8241769

一、二文中知道，无论PyObject还是PyXXXObject，都包含有那么几样东西。

具体举个例子来说，PyIntObject里面有三东西：

int ob_refcnt;//引用计数
struct _typeobject *ob_type; //一堆信息
long ob_ival; //值

只要把这三个要素构成了，不就生成一个基本的"int"了？？是不是？？

故在intobject.c中有如下代码出现。PyTypeObject就是_typeobject。

[plain] view plaincopy
PyTypeObject PyInt_Type = {  
    PyVarObject_HEAD_INIT(&PyType_Type, 0)  
    "int",  
    sizeof(PyIntObject),  
    0,  
    (destructor)int_dealloc,                    /* tp_dealloc */  
    (printfunc)int_print,                       /* tp_print */  
    0,                                          /* tp_getattr */  
    0,                                          /* tp_setattr */  
    (cmpfunc)int_compare,                       /* tp_compare */  
    (reprfunc)int_to_decimal_string,            /* tp_repr */  
    &int_as_number,                             /* tp_as_number */  
    0,                                          /* tp_as_sequence */  
    0,                                          /* tp_as_mapping */  
    (hashfunc)int_hash,                         /* tp_hash */  
    0,                                          /* tp_call */  
    (reprfunc)int_to_decimal_string,            /* tp_str */  
    PyObject_GenericGetAttr,                    /* tp_getattro */  
    0,                                          /* tp_setattro */  
    0,                                          /* tp_as_buffer */  
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES |  
        Py_TPFLAGS_BASETYPE | Py_TPFLAGS_INT_SUBCLASS,          /* tp_flags */  
    int_doc,                                    /* tp_doc */  
    0,                                          /* tp_traverse */  
    0,                                          /* tp_clear */  
    0,                                          /* tp_richcompare */  
    0,                                          /* tp_weaklistoffset */  
    0,                                          /* tp_iter */  
    0,                                          /* tp_iternext */  
    int_methods,                                /* tp_methods */  
    0,                                          /* tp_members */  
    int_getset,                                 /* tp_getset */  
    0,                                          /* tp_base */  
    0,                                          /* tp_dict */  
    0,                                          /* tp_descr_get */  
    0,                                          /* tp_descr_set */  
    0,                                          /* tp_dictoffset */  
    0,                                          /* tp_init */  
    0,                                          /* tp_alloc */  
    int_new,                                    /* tp_new */  
    (freefunc)int_free,                         /* tp_free */  
};  

总结：在XXXobject.c中，通过声明定义变量PyXXX_Type(PyTypeObject类型的)创建了一个XXX对象。

创建过程会调用一系列函数，具体过程是：tp_new(C++中的new)，设置sizeof(PyIntObject)，tp_init(视为类的构造函数)

参考：https://github.com/youngsterxyf/Translation/blob/master/Python-object-creation-sequence.rst