Object Protocol
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PyObject* Py_NotImplemented

   The "NotImplemented" singleton, used to signal that an operation is
   not implemented for the given type combination.

Py_RETURN_NOTIMPLEMENTED

   Properly handle returning "Py_NotImplemented" from within a C
   function (that is, increment the reference count of NotImplemented
   and return it).

int PyObject_Print(PyObject *o, FILE *fp, int flags)

   Print an object *o*, on file *fp*.  Returns "-1" on error.  The
   flags argument is used to enable certain printing options.  The
   only option currently supported is "Py_PRINT_RAW"; if given, the
   "str()" of the object is written instead of the "repr()".

int PyObject_HasAttr(PyObject *o, PyObject *attr_name)

   Returns "1" if *o* has the attribute *attr_name*, and "0"
   otherwise.  This is equivalent to the Python expression "hasattr(o,
   attr_name)".  This function always succeeds.

   Note that exceptions which occur while calling "__getattr__()" and
   "__getattribute__()" methods will get suppressed. To get error
   reporting use "PyObject_GetAttr()" instead.

int PyObject_HasAttrString(PyObject *o, const char *attr_name)

   Returns "1" if *o* has the attribute *attr_name*, and "0"
   otherwise.  This is equivalent to the Python expression "hasattr(o,
   attr_name)".  This function always succeeds.

   Note that exceptions which occur while calling "__getattr__()" and
   "__getattribute__()" methods and creating a temporary string object
   will get suppressed. To get error reporting use
   "PyObject_GetAttrString()" instead.

PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name)
    *Return value: New reference.*

   Retrieve an attribute named *attr_name* from object *o*. Returns
   the attribute value on success, or *NULL* on failure.  This is the
   equivalent of the Python expression "o.attr_name".

PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name)
    *Return value: New reference.*

   Retrieve an attribute named *attr_name* from object *o*. Returns
   the attribute value on success, or *NULL* on failure. This is the
   equivalent of the Python expression "o.attr_name".

PyObject* PyObject_GenericGetAttr(PyObject *o, PyObject *name)

   Generic attribute getter function that is meant to be put into a
   type object's "tp_getattro" slot.  It looks for a descriptor in the
   dictionary of classes in the object's MRO as well as an attribute
   in the object's "__dict__" (if present).  As outlined in 实现描述器
   , data descriptors take preference over instance attributes, while
   non-data descriptors don't.  Otherwise, an "AttributeError" is
   raised.

int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v)

   Set the value of the attribute named *attr_name*, for object *o*,
   to the value *v*. Raise an exception and return "-1" on failure;
   return "0" on success.  This is the equivalent of the Python
   statement "o.attr_name = v".

   If *v* is *NULL*, the attribute is deleted, however this feature is
   deprecated in favour of using "PyObject_DelAttr()".

int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)

   Set the value of the attribute named *attr_name*, for object *o*,
   to the value *v*. Raise an exception and return "-1" on failure;
   return "0" on success.  This is the equivalent of the Python
   statement "o.attr_name = v".

   If *v* is *NULL*, the attribute is deleted, however this feature is
   deprecated in favour of using "PyObject_DelAttrString()".

int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)

   Generic attribute setter and deleter function that is meant to be
   put into a type object's "tp_setattro" slot.  It looks for a data
   descriptor in the dictionary of classes in the object's MRO, and if
   found it takes preference over setting or deleting the attribute in
   the instance dictionary. Otherwise, the attribute is set or deleted
   in the object's "__dict__" (if present). On success, "0" is
   returned, otherwise an "AttributeError" is raised and "-1" is
   returned.

int PyObject_DelAttr(PyObject *o, PyObject *attr_name)

   Delete attribute named *attr_name*, for object *o*. Returns "-1" on
   failure. This is the equivalent of the Python statement "del
   o.attr_name".

int PyObject_DelAttrString(PyObject *o, const char *attr_name)

   Delete attribute named *attr_name*, for object *o*. Returns "-1" on
   failure. This is the equivalent of the Python statement "del
   o.attr_name".

PyObject* PyObject_GenericGetDict(PyObject *o, void *context)

   A generic implementation for the getter of a "__dict__" descriptor.
   It creates the dictionary if necessary.

   3.3 新版功能.

int PyObject_GenericSetDict(PyObject *o, void *context)

   A generic implementation for the setter of a "__dict__" descriptor.
   This implementation does not allow the dictionary to be deleted.

   3.3 新版功能.

PyObject* PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid)
    *Return value: New reference.*

   Compare the values of *o1* and *o2* using the operation specified
   by *opid*, which must be one of "Py_LT", "Py_LE", "Py_EQ", "Py_NE",
   "Py_GT", or "Py_GE", corresponding to "<", "<=", "==", "!=", ">",
   or ">=" respectively. This is the equivalent of the Python
   expression "o1 op o2", where "op" is the operator corresponding to
   *opid*. Returns the value of the comparison on success, or *NULL*
   on failure.

int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid)

   Compare the values of *o1* and *o2* using the operation specified
   by *opid*, which must be one of "Py_LT", "Py_LE", "Py_EQ", "Py_NE",
   "Py_GT", or "Py_GE", corresponding to "<", "<=", "==", "!=", ">",
   or ">=" respectively. Returns "-1" on error, "0" if the result is
   false, "1" otherwise. This is the equivalent of the Python
   expression "o1 op o2", where "op" is the operator corresponding to
   *opid*.

注解: If *o1* and *o2* are the same object,
  "PyObject_RichCompareBool()" will always return "1" for "Py_EQ" and
  "0" for "Py_NE".

PyObject* PyObject_Repr(PyObject *o)
    *Return value: New reference.*

   Compute a string representation of object *o*.  Returns the string
   representation on success, *NULL* on failure.  This is the
   equivalent of the Python expression "repr(o)".  Called by the
   "repr()" built-in function.

   在 3.4 版更改: This function now includes a debug assertion to help
   ensure that it does not silently discard an active exception.

PyObject* PyObject_ASCII(PyObject *o)

   As "PyObject_Repr()", compute a string representation of object
   *o*, but escape the non-ASCII characters in the string returned by
   "PyObject_Repr()" with "\x", "\u" or "\U" escapes.  This generates
   a string similar to that returned by "PyObject_Repr()" in Python 2.
   Called by the "ascii()" built-in function.

PyObject* PyObject_Str(PyObject *o)
    *Return value: New reference.*

   Compute a string representation of object *o*.  Returns the string
   representation on success, *NULL* on failure.  This is the
   equivalent of the Python expression "str(o)".  Called by the
   "str()" built-in function and, therefore, by the "print()"
   function.

   在 3.4 版更改: This function now includes a debug assertion to help
   ensure that it does not silently discard an active exception.

PyObject* PyObject_Bytes(PyObject *o)

   Compute a bytes representation of object *o*.  *NULL* is returned
   on failure and a bytes object on success.  This is equivalent to
   the Python expression "bytes(o)", when *o* is not an integer.
   Unlike "bytes(o)", a TypeError is raised when *o* is an integer
   instead of a zero-initialized bytes object.

int PyObject_IsSubclass(PyObject *derived, PyObject *cls)

   Return "1" if the class *derived* is identical to or derived from
   the class *cls*, otherwise return "0".  In case of an error, return
   "-1".

   If *cls* is a tuple, the check will be done against every entry in
   *cls*. The result will be "1" when at least one of the checks
   returns "1", otherwise it will be "0".

   If *cls* has a "__subclasscheck__()" method, it will be called to
   determine the subclass status as described in **PEP 3119**.
   Otherwise, *derived* is a subclass of *cls* if it is a direct or
   indirect subclass, i.e. contained in "cls.__mro__".

   Normally only class objects, i.e. instances of "type" or a derived
   class, are considered classes.  However, objects can override this
   by having a "__bases__" attribute (which must be a tuple of base
   classes).

int PyObject_IsInstance(PyObject *inst, PyObject *cls)

   Return "1" if *inst* is an instance of the class *cls* or a
   subclass of *cls*, or "0" if not.  On error, returns "-1" and sets
   an exception.

   If *cls* is a tuple, the check will be done against every entry in
   *cls*. The result will be "1" when at least one of the checks
   returns "1", otherwise it will be "0".

   If *cls* has a "__instancecheck__()" method, it will be called to
   determine the subclass status as described in **PEP 3119**.
   Otherwise, *inst* is an instance of *cls* if its class is a
   subclass of *cls*.

   An instance *inst* can override what is considered its class by
   having a "__class__" attribute.

   An object *cls* can override if it is considered a class, and what
   its base classes are, by having a "__bases__" attribute (which must
   be a tuple of base classes).

int PyCallable_Check(PyObject *o)

   Determine if the object *o* is callable.  Return "1" if the object
   is callable and "0" otherwise.  This function always succeeds.

PyObject* PyObject_Call(PyObject *callable_object, PyObject *args, PyObject *kw)
    *Return value: New reference.*

   Call a callable Python object *callable_object*, with arguments
   given by the tuple *args*, and named arguments given by the
   dictionary *kw*. If no named arguments are needed, *kw* may be
   *NULL*. *args* must not be *NULL*, use an empty tuple if no
   arguments are needed. Returns the result of the call on success, or
   *NULL* on failure.  This is the equivalent of the Python expression
   "callable_object(*args, **kw)".

PyObject* PyObject_CallObject(PyObject *callable_object, PyObject *args)
    *Return value: New reference.*

   Call a callable Python object *callable_object*, with arguments
   given by the tuple *args*.  If no arguments are needed, then *args*
   may be *NULL*.  Returns the result of the call on success, or
   *NULL* on failure.  This is the equivalent of the Python expression
   "callable_object(*args)".

PyObject* PyObject_CallFunction(PyObject *callable, const char *format, ...)
    *Return value: New reference.*

   Call a callable Python object *callable*, with a variable number of
   C arguments. The C arguments are described using a
   "Py_BuildValue()" style format string.  The format may be *NULL*,
   indicating that no arguments are provided. Returns the result of
   the call on success, or *NULL* on failure.  This is the equivalent
   of the Python expression "callable(*args)". Note that if you only
   pass "PyObject *" args, "PyObject_CallFunctionObjArgs()" is a
   faster alternative.

   在 3.4 版更改: The type of *format* was changed from "char *".

PyObject* PyObject_CallMethod(PyObject *o, const char *method, const char *format, ...)
    *Return value: New reference.*

   Call the method named *method* of object *o* with a variable number
   of C arguments.  The C arguments are described by a
   "Py_BuildValue()" format string that should  produce a tuple.  The
   format may be *NULL*, indicating that no arguments are provided.
   Returns the result of the call on success, or *NULL* on failure.
   This is the equivalent of the Python expression "o.method(args)".
   Note that if you only pass "PyObject *" args,
   "PyObject_CallMethodObjArgs()" is a faster alternative.

   在 3.4 版更改: The types of *method* and *format* were changed from
   "char *".

PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL)
    *Return value: New reference.*

   Call a callable Python object *callable*, with a variable number of
   "PyObject*" arguments.  The arguments are provided as a variable
   number of parameters followed by *NULL*. Returns the result of the
   call on success, or *NULL* on failure.

PyObject* PyObject_CallMethodObjArgs(PyObject *o, PyObject *name, ..., NULL)
    *Return value: New reference.*

   Calls a method of the object *o*, where the name of the method is
   given as a Python string object in *name*.  It is called with a
   variable number of "PyObject*" arguments.  The arguments are
   provided as a variable number of parameters followed by *NULL*.
   Returns the result of the call on success, or *NULL* on failure.

Py_hash_t PyObject_Hash(PyObject *o)

   Compute and return the hash value of an object *o*.  On failure,
   return "-1". This is the equivalent of the Python expression
   "hash(o)".

   在 3.2 版更改: The return type is now Py_hash_t.  This is a signed
   integer the same size as Py_ssize_t.

Py_hash_t PyObject_HashNotImplemented(PyObject *o)

   Set a "TypeError" indicating that "type(o)" is not hashable and
   return "-1". This function receives special treatment when stored
   in a "tp_hash" slot, allowing a type to explicitly indicate to the
   interpreter that it is not hashable.

int PyObject_IsTrue(PyObject *o)

   Returns "1" if the object *o* is considered to be true, and "0"
   otherwise. This is equivalent to the Python expression "not not o".
   On failure, return "-1".

int PyObject_Not(PyObject *o)

   Returns "0" if the object *o* is considered to be true, and "1"
   otherwise. This is equivalent to the Python expression "not o".  On
   failure, return "-1".

PyObject* PyObject_Type(PyObject *o)
    *Return value: New reference.*

   When *o* is non-*NULL*, returns a type object corresponding to the
   object type of object *o*. On failure, raises "SystemError" and
   returns *NULL*.  This is equivalent to the Python expression
   "type(o)". This function increments the reference count of the
   return value. There's really no reason to use this function instead
   of the common expression "o->ob_type", which returns a pointer of
   type "PyTypeObject*", except when the incremented reference count
   is needed.

int PyObject_TypeCheck(PyObject *o, PyTypeObject *type)

   Return true if the object *o* is of type *type* or a subtype of
   *type*.  Both parameters must be non-*NULL*.

Py_ssize_t PyObject_Size(PyObject *o)
Py_ssize_t PyObject_Length(PyObject *o)

   Return the length of object *o*.  If the object *o* provides either
   the sequence and mapping protocols, the sequence length is
   returned.  On error, "-1" is returned.  This is the equivalent to
   the Python expression "len(o)".

Py_ssize_t PyObject_LengthHint(PyObject *o, Py_ssize_t default)

   Return an estimated length for the object *o*. First try to return
   its actual length, then an estimate using "__length_hint__()", and
   finally return the default value. On error return "-1". This is the
   equivalent to the Python expression "operator.length_hint(o,
   default)".

   3.4 新版功能.

PyObject* PyObject_GetItem(PyObject *o, PyObject *key)
    *Return value: New reference.*

   Return element of *o* corresponding to the object *key* or *NULL*
   on failure. This is the equivalent of the Python expression
   "o[key]".

int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v)

   Map the object *key* to the value *v*.  Raise an exception and
   return "-1" on failure; return "0" on success.  This is the
   equivalent of the Python statement "o[key] = v".

int PyObject_DelItem(PyObject *o, PyObject *key)

   Remove the mapping for the object *key* from the object *o*.
   Return "-1" on failure.  This is equivalent to the Python statement
   "del o[key]".

PyObject* PyObject_Dir(PyObject *o)
    *Return value: New reference.*

   This is equivalent to the Python expression "dir(o)", returning a
   (possibly empty) list of strings appropriate for the object
   argument, or *NULL* if there was an error.  If the argument is
   *NULL*, this is like the Python "dir()", returning the names of the
   current locals; in this case, if no execution frame is active then
   *NULL* is returned but "PyErr_Occurred()" will return false.

PyObject* PyObject_GetIter(PyObject *o)
    *Return value: New reference.*

   This is equivalent to the Python expression "iter(o)". It returns a
   new iterator for the object argument, or the object  itself if the
   object is already an iterator.  Raises "TypeError" and returns
   *NULL* if the object cannot be iterated.
