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# Mapping Protocol

int `PyMapping_Check`(PyObject *o)

  Return `1` if the object provides mapping protocol, and `0` otherwise. This function always succeeds.

Py_ssize_t `PyMapping_Size`(PyObject *o)
Py_ssize_t `PyMapping_Length`(PyObject *o)

  Returns the number of keys in object o on success, and `-1` on failure. For objects that do not provide mapping protocol, this is equivalent to the Python expression `len(o)`.

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

int `PyMapping_DelItemString`(PyObject *o, char *key)

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

int `PyMapping_DelItem`(PyObject *o, PyObject *key)

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

int `PyMapping_HasKeyString`(PyObject *o, char *key)

  On success, return `1` if the mapping object has the key key and `0` otherwise. This is equivalent to `o[key]`, returning `True` on success and `False` on an exception. This function always succeeds.

int `PyMapping_HasKey`(PyObject *o, PyObject *key)

  Return `1` if the mapping object has the key key and `0` otherwise. This is equivalent to `o[key]`, returning `True` on success and `False` on an exception. This function always succeeds.

PyObject* `PyMapping_Keys`(PyObject *o)
  Return value: New reference.

  On success, return a list of the keys in object o. On failure, return NULL. This is equivalent to the Python expression `o.keys()`.

PyObject* `PyMapping_Values`(PyObject *o)
  Return value: New reference.

  On success, return a list of the values in object o. On failure, return NULL. This is equivalent to the Python expression `o.values()`.

PyObject* `PyMapping_Items`(PyObject *o)
  Return value: New reference.

  On success, return a list of the items in object o, where each item is a tuple containing a key-value pair. On failure, return NULL. This is equivalent to the Python expression `o.items()`.

PyObject* `PyMapping_GetItemString`(PyObject *o, char *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 `PyMapping_SetItemString`(PyObject *o, char *key, PyObject *v)

  Map the object key to the value v in object o. Returns `-1` on failure. This is the equivalent of the Python statement `o[key] = v`.