Object Protocol
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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.

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.

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_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".

int PyObject_Cmp(PyObject *o1, PyObject *o2, int *result)

   Compare the values of *o1* and *o2* using a routine provided by
   *o1*, if one exists, otherwise with a routine provided by *o2*.
   The result of the comparison is returned in *result*.  Returns "-1"
   on failure.  This is the equivalent of the Python statement "result
   = cmp(o1, o2)".

int PyObject_Compare(PyObject *o1, PyObject *o2)

   Compare the values of *o1* and *o2* using a routine provided by
   *o1*, if one exists, otherwise with a routine provided by *o2*.
   Returns the result of the comparison on success.  On error, the
   value returned is undefined; use "PyErr_Occurred()" to detect an
   error.  This is equivalent to the Python expression "cmp(o1, o2)".

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 and by reverse quotes.

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 by the "print" statement.

PyObject* PyObject_Bytes(PyObject *o)

   Compute a bytes representation of object *o*.  In 2.x, this is just
   an alias for "PyObject_Str()".

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

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

int PyObject_IsInstance(PyObject *inst, PyObject *cls)

   Returns "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 type object rather than a class
   object, "PyObject_IsInstance()" returns "1" if *inst* is of type
   *cls*.  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 *inst* is not a
   class instance and *cls* is neither a type object, nor a class
   object, nor a tuple, *inst* must have a "__class__" attribute — the
   class relationship of the value of that attribute with *cls* will
   be used to determine the result of this function.

   2.1 新版功能.

   在 2.2 版更改: Support for a tuple as the second argument added.

Subclass determination is done in a fairly straightforward way, but
includes a wrinkle that implementors of extensions to the class system
may want to be aware of.  If "A" and "B" are class objects, "B" is a
subclass of "A" if it inherits from "A" either directly or indirectly.
If either is not a class object, a more general mechanism is used to
determine the class relationship of the two objects.  When testing if
*B* is a subclass of *A*, if *A* is *B*, "PyObject_IsSubclass()"
returns true.  If *A* and *B* are different objects, *B*’s "__bases__"
attribute is searched in a depth-first fashion for *A* — the presence
of the "__bases__" attribute is considered sufficient for this
determination.

int PyObject_IsSubclass(PyObject *derived, PyObject *cls)

   Returns "1" if the class *derived* is identical to or derived from
   the class *cls*, otherwise returns "0".  In case of an error,
   returns "-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 either
   *derived* or *cls* is not an actual class object (or tuple), this
   function uses the generic algorithm described above.

   2.1 新版功能.

   在 2.3 版更改: Older versions of Python did not support a tuple as
   the second argument.

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
   "apply(callable_object, args, kw)" or "callable_object(*args,
   **kw)".

   2.2 新版功能.

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
   "apply(callable_object, args)" or "callable_object(*args)".

PyObject* PyObject_CallFunction(PyObject *callable, 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 "apply(callable, args)" or
   "callable(*args)". Note that if you only pass "PyObject *" args,
   "PyObject_CallFunctionObjArgs()" is a faster alternative.

PyObject* PyObject_CallMethod(PyObject *o, char *method, 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.

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.

   2.2 新版功能.

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.

   2.2 新版功能.

long 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)".

long 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.

   2.6 新版功能.

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*.

   2.2 新版功能.

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

   在 2.5 版更改: These functions returned an "int" type. This might
   require changes in your code for properly supporting 64-bit
   systems.

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)

   Delete the mapping for *key* from *o*.  Returns "-1" on failure.
   This is the equivalent of the Python statement "del o[key]".

int PyObject_AsFileDescriptor(PyObject *o)

   Derives a file descriptor from a Python object.  If the object is
   an integer or long integer, its value is returned.  If not, the
   object’s "fileno()" method is called if it exists; the method must
   return an integer or long integer, which is returned as the file
   descriptor value.  Returns "-1" on failure.

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.
