#include <db.h>

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

The DB->fd() method provides access to a file descriptor representative of the underlying database. A file descriptor referring to the same file will be returned to all processes that call DB->open() with the same file parameter.

This file descriptor may be safely used as a parameter to the fcntl(2) and flock(2) locking functions.

The DB->fd() method only supports a coarse-grained form of locking. Applications should instead use the Berkeley DB lock manager where possible.

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