/*
 * TYPEDEF: SE_Search_Filter
 *
 *   Pointer to a search filter.  The definition of a search filter is
 *   hidden by the implementation of this API.  The user of this API simply
 *   passes in and receives back an SE_Search_Filter for functions
 *   that deal with search filters.
 *
 *    A search filter is an opaque data type, created by calling
 *    SE_CreateSearchFilter(), which provides a set of rules that are used
 *    by iterators to filter objects so that only objects that pass the
 *    rules will be returned to the user.
 *
 *    Search filters have the following characteristics:
 *
 *    1. A search filter must be created by SE_CreateSearchFilter() before
 *       it is used.
 *    2. To use a search filter after it has been defined, pass the search
 *       filter to an iterator when initializing the iterator.
 *    3. Search filters can be freed at any time; a search filter does *NOT*
 *       need to stay in existence until the iterator(s) that depend on that
 *       filter are freed. (An iterator retains a copy of any search filter
 *       used to initialize that iterator).
 *    4. A search filter must be freed by SE_FreeSearchFilter() after the
 *       user is done with it.
 *
 *    See also SE_CreateSearchFilter(), SE_FreeSearchFilter().
 */