# DB->set_h_nelem

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    #include <db.h>

    int
    DB->set_h_nelem(DB *db, u_int32_t h_nelem);

# Description

Set an estimate of the final size of the hash table.

If not set or set too low, hash tables will still expand gracefully as keys are entered, although a slight performance degradation may be noticed.

The DB->set_h_nelem interface may be used only to configure Berkeley DB before the DB->open interface is called.

The DB->set_h_nelem function returns a non-zero error value on failure and 0 on success.

# Errors

The DB->set_h_nelem function may fail and return a non-zero error for the following conditions:

EINVAL
  An invalid flag value or parameter was specified.

  Called after DB->open was called.

The DB->set_h_nelem 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 DB->set_h_nelem function may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.

# See Also

db_create, DB->associate, DB->close, DB->cursor, DB->del, DB->err, DB->errx DB->fd, DB->get, DB->pget, DB->get_byteswapped, DB->get_type, DB->join, DB->key_range, DB->open, DB->put, DB->remove, DB->rename, DB->set_alloc, DB->set_append_recno, DB->set_bt_compare, DB->set_bt_minkey, DB->set_bt_prefix, DB->set_cachesize, DB->set_dup_compare, DB->set_errcall, DB->set_errfile, DB->set_errpfx, DB->set_feedback, DB->set_flags, DB->set_h_ffactor, DB->set_h_hash, DB->set_h_nelem, DB->set_lorder, DB->set_pagesize, DB->set_paniccall, DB->set_q_extentsize, DB->set_re_delim, DB->set_re_len, DB->set_re_pad, DB->set_re_source, DB->stat, DB->sync, DB->truncate, DB->upgrade, and DB->verify.`

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