# DB->fd |

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    #include <db.h>

    int
    DB->fd(DB *db, int *fdp);

# Description

The DB->fd function copies a file descriptor representative of the underlying database into the memory referenced by fdp. A file descriptor referencing the same file will be returned to all processes that call DB->open with the same file argument. This file descriptor may be safely used as an argument to the fcntl(2) and flock(2) locking functions. The file descriptor is not necessarily associated with any of the underlying files actually used by the access method.

The DB->fd function only supports a coarse-grained form of locking. Applications should use the lock manager where possible.

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

# Errors

If a fatal error occurs in Berkeley DB, the DB->fd function will fail and return DB_RUNRECOVERY, at which point all subsequent database calls will fail in the same way.

In addition, the DB->fd function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.

# See Also

db_create, DB->close, DB->cursor, DB->del, DB->err, DB->fd, DB->get, DB->get_byteswapped, DB->get_type, DB->join, DB->open, DB->put, DB->remove, 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_flags, DB->set_h_ffactor, DB->set_h_hash, DB->set_h_nelem, DB->set_lorder, DB->set_malloc, DB->set_pagesize, DB->set_paniccall, DB->set_realloc, DB->set_re_delim, DB->set_re_len, DB->set_re_pad, DB->set_re_source, DB->stat, DB->sync and DB->upgrade.`

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