int DBC->c_count(DBC *cursor, db_recno_t *countp, u_int32_t flags);
The DBcursor->c_count function returns a count of the number of duplicate data items for the key to which the cursor refers, into the memory location to which countp refers. If the underlying database does not support duplicate data items, the call will still succeed and a count of 1 will be returned.
The flags parameter is currently unused, and must be set to 0.
If the cursor argument is not yet initialized, the DBcursor->c_count function will return EINVAL.
Otherwise, the DBcursor->c_count function returns a non-zero error value on failure and 0 on success.
The DBcursor->c_count function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DBcursor->c_count function may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.
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