python源码剖析sizeof(PyIntObject)

在读python源码剖析的时候发现书上标记的

sizeof(PyIntObject)大小为10，自己动手测了一把为12，因此发现自己动手很有必要~~~~~~~~~

#include  
#include  
#include  
typedef int Py_ssize_t;
#define PyObject_HEAD                   \
    Py_ssize_t ob_refcnt;               \
    struct _typeobject *ob_type;
#define PyObject_VAR_HEAD               \
    PyObject_HEAD                       \
    Py_ssize_t ob_size; /* Number of items in variable part */
typedef struct _object {
    PyObject_HEAD
} PyObject;  
/* */
/*************** function pointer*****************/
typedef struct bufferinfo {
    void *buf;
    PyObject *obj;        /* owned reference */
    Py_ssize_t len;
    Py_ssize_t itemsize;  /* This is Py_ssize_t so it can be
                             pointed to by strides in simple case.*/
    int readonly;
    int ndim;
    char *format;
    Py_ssize_t *shape;
    Py_ssize_t *strides;
    Py_ssize_t *suboffsets;
    Py_ssize_t smalltable[2];  /* static store for shape and strides of
                                  mono-dimensional buffers. */
    void *internal;
} Py_buffer;
typedef void (*freefunc)(void *);
typedef void (*destructor)(PyObject *);
typedef int (*printfunc)(PyObject *, FILE *, int);
typedef PyObject *(*getattrfunc)(PyObject *, char *);
typedef PyObject *(*getattrofunc)(PyObject *, PyObject *);
typedef int (*setattrfunc)(PyObject *, char *, PyObject *);
typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *);
typedef int (*cmpfunc)(PyObject *, PyObject *);
typedef PyObject *(*reprfunc)(PyObject *);
typedef long (*hashfunc)(PyObject *);
typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int);
typedef PyObject *(*getiterfunc) (PyObject *);
typedef PyObject *(*iternextfunc) (PyObject *);
typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *);
typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *);
typedef int (*initproc)(PyObject *, PyObject *, PyObject *);
typedef PyObject *(*newfunc)(struct _typeobject *, PyObject *, PyObject *);
typedef PyObject *(*allocfunc)(struct _typeobject *, Py_ssize_t);
typedef PyObject * (*unaryfunc)(PyObject *);
typedef PyObject * (*binaryfunc)(PyObject *, PyObject *);
typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *);
typedef int (*inquiry)(PyObject *);
typedef Py_ssize_t (*lenfunc)(PyObject *);
typedef int (*coercion)(PyObject **, PyObject **);
/*typedef PyObject *(*intargfunc)(PyObject *, int) Py_DEPRECATED(2.5);
typedef PyObject *(*intintargfunc)(PyObject *, int, int) Py_DEPRECATED(2.5); */
typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);
typedef int(*intobjargproc)(PyObject *, int, PyObject *);
typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *);
typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *);
typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *);
typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *);

typedef int (*objobjproc)(PyObject *, PyObject *);
typedef int (*visitproc)(PyObject *, void *);
typedef int (*traverseproc)(PyObject *, visitproc, void *);
typedef int (*getbufferproc)(PyObject *, Py_buffer *, int);
/* int-based buffer interface */
typedef int (*getreadbufferproc)(PyObject *, int, void **);
typedef int (*getwritebufferproc)(PyObject *, int, void **);
typedef int (*getsegcountproc)(PyObject *, int *);
typedef int (*getcharbufferproc)(PyObject *, int, char **);
/* ssize_t-based buffer interface */
typedef Py_ssize_t (*readbufferproc)(PyObject *, Py_ssize_t, void **);
typedef Py_ssize_t (*writebufferproc)(PyObject *, Py_ssize_t, void **);
typedef Py_ssize_t (*segcountproc)(PyObject *, Py_ssize_t *);
typedef Py_ssize_t (*charbufferproc)(PyObject *, Py_ssize_t, char **);
typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
typedef struct {
    /* For numbers without flag bit Py_TPFLAGS_CHECKTYPES set, all
       arguments are guaranteed to be of the object's type (modulo
       coercion hacks -- i.e. if the type's coercion function
       returns other types, then these are allowed as well).  Numbers that
       have the Py_TPFLAGS_CHECKTYPES flag bit set should check *both*
       arguments for proper type and implement the necessary conversions
       in the slot functions themselves. */

    binaryfunc nb_add;
    binaryfunc nb_subtract;
    binaryfunc nb_multiply;
    binaryfunc nb_divide;
    binaryfunc nb_remainder;
    binaryfunc nb_divmod;
    ternaryfunc nb_power;
    unaryfunc nb_negative;
    unaryfunc nb_positive;
    unaryfunc nb_absolute;
    inquiry nb_nonzero;
    unaryfunc nb_invert;
    binaryfunc nb_lshift;
    binaryfunc nb_rshift;
    binaryfunc nb_and;
    binaryfunc nb_xor;
    binaryfunc nb_or;
    coercion nb_coerce;
    unaryfunc nb_int;
    unaryfunc nb_long;
    unaryfunc nb_float;
    unaryfunc nb_oct;
    unaryfunc nb_hex;
    /* Added in release 2.0 */
    binaryfunc nb_inplace_add;
    binaryfunc nb_inplace_subtract;
    binaryfunc nb_inplace_multiply;
    binaryfunc nb_inplace_divide;
    binaryfunc nb_inplace_remainder;
    ternaryfunc nb_inplace_power;
    binaryfunc nb_inplace_lshift;
    binaryfunc nb_inplace_rshift;
    binaryfunc nb_inplace_and;
    binaryfunc nb_inplace_xor;
    binaryfunc nb_inplace_or;

    /* Added in release 2.2 */
    /* The following require the Py_TPFLAGS_HAVE_CLASS flag */
    binaryfunc nb_floor_divide;
    binaryfunc nb_true_divide;
    binaryfunc nb_inplace_floor_divide;
    binaryfunc nb_inplace_true_divide;

    /* Added in release 2.5 */
    unaryfunc nb_index;
} PyNumberMethods;
typedef struct {
    lenfunc sq_length;
    binaryfunc sq_concat;
    ssizeargfunc sq_repeat;
    ssizeargfunc sq_item;
    ssizessizeargfunc sq_slice;
    ssizeobjargproc sq_ass_item;
    ssizessizeobjargproc sq_ass_slice;
    objobjproc sq_contains;
    /* Added in release 2.0 */
    binaryfunc sq_inplace_concat;
    ssizeargfunc sq_inplace_repeat;
} PySequenceMethods;
typedef struct {
    lenfunc mp_length;
    binaryfunc mp_subscript;
    objobjargproc mp_ass_subscript;
} PyMappingMethods;
typedef struct {
    readbufferproc bf_getreadbuffer;
    writebufferproc bf_getwritebuffer;
    segcountproc bf_getsegcount;
    charbufferproc bf_getcharbuffer;
    getbufferproc bf_getbuffer;
    releasebufferproc bf_releasebuffer;
}PyBufferProcs;

typedef struct _typeobject {
    PyObject_VAR_HEAD
    const char *tp_name; /* For printing, in format "." */
    Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

    /* Methods to implement standard operations */

    destructor tp_dealloc;
    printfunc tp_print;
    getattrfunc tp_getattr;
    setattrfunc tp_setattr;
    cmpfunc tp_compare;
    reprfunc tp_repr;

    /* Method suites for standard classes */

    PyNumberMethods *tp_as_number;
    PySequenceMethods *tp_as_sequence;
    PyMappingMethods *tp_as_mapping;

    /* More standard operations (here for binary compatibility) */

    hashfunc tp_hash;
    ternaryfunc tp_call;
    reprfunc tp_str;
    getattrofunc tp_getattro;
    setattrofunc tp_setattro;

    /* Functions to access object as input/output buffer */
    PyBufferProcs * tp_as_buffer;

    /* Flags to define presence of optional/expanded features */
    long tp_flags;

    const char *tp_doc; /* Documentation string */

    /* Assigned meaning in release 2.0 */
    /* call function for all accessible objects */
    traverseproc tp_traverse;

    /* delete references to contained objects */
    inquiry tp_clear;

    /* Assigned meaning in release 2.1 */
    /* rich comparisons */
    richcmpfunc tp_richcompare;

    /* weak reference enabler */
    Py_ssize_t tp_weaklistoffset;

    /* Added in release 2.2 */
    /* Iterators */
    getiterfunc tp_iter;
    iternextfunc tp_iternext;

    /* Attribute descriptor and subclassing stuff */
    struct PyMethodDef *tp_methods;
    struct PyMemberDef *tp_members;
    struct PyGetSetDef *tp_getset;
    struct _typeobject *tp_base;
    PyObject *tp_dict;
    descrgetfunc tp_descr_get;
    descrsetfunc tp_descr_set;
    Py_ssize_t tp_dictoffset;
    initproc tp_init;
    allocfunc tp_alloc;
    newfunc tp_new;
    freefunc tp_free; /* Low-level free-memory routine */
    inquiry tp_is_gc; /* For PyObject_IS_GC */
    PyObject *tp_bases;
    PyObject *tp_mro; /* method resolution order */
    PyObject *tp_cache;
    PyObject *tp_subclasses;
    PyObject *tp_weaklist;
    destructor tp_del;

    /* Type attribute cache version tag. Added in version 2.6 */
    unsigned int tp_version_tag;

#ifdef COUNT_ALLOCS
    /* these must be last and never explicitly initialized */
    Py_ssize_t tp_allocs;
    Py_ssize_t tp_frees;
    Py_ssize_t tp_maxalloc;
    struct _typeobject *tp_prev;
    struct _typeobject *tp_next;
#endif
}PyTypeObject;
typedef struct {
    PyObject_HEAD
    long ob_ival;
} PyIntObject;


int main(int argc,char * argv[]){
	printf("size of python int is \t%d\t\n",sizeof(PyIntObject));
}

ref： python源码分析 python MANUAL