Berkeley DB: DbInfo::set_bt_compare
Полезная информация


#include <db_cxx.h>

typedef int (*bt_compare_fcn)(const DBT *, const DBT *); void DbInfo::set_bt_compare(bt_compare_fcn);


Set the Btree key comparison function. This comparison function must return an integer less than, equal to, or greater than zero if the first key argument is considered to be respectively less than, equal to, or greater than the second key argument. The same comparison method must be used on a given tree every time it is opened.

The data and size fields of the Dbt are the only fields that may be used for the purposes of this comparison.

If no comparison function is specified, the keys are compared lexically, with shorter keys collating before longer keys.



See Also

DbInfo::set_bt_compare, DbInfo::set_bt_maxkey, DbInfo::set_bt_minkey, DbInfo::set_bt_prefix, DbInfo::set_cachesize, DbInfo::set_compare, DbInfo::set_flags, DbInfo::set_h_ffactor, DbInfo::set_h_hash, DbInfo::set_h_nelem, DbInfo::set_lorder, DbInfo::set_malloc, DbInfo::set_pagesize, DbInfo::set_re_delim, DbInfo::set_re_len, DbInfo::set_re_pad and DbInfo::set_re_source.