.. efun:: int m_contains(mixed &data1, ..., &dataN, map, key)

  If the mapping contains the key map, the corresponding values are assigned to the data arguments, which must be passed by reference, and 1 is returned. If key is not in map, 0 is returned and the data args are left unchanged. It is possible to use this function for a 0-value mapping, in which case it has the same effect as :efun:`member`.

  :history 3.2.6 changed: Renamed from 'mapping_contains()'.

  .. seealso:: :efun:`m_entry`, :type:`mapping`, :efun:`member`