https://stuff.mit.edu/afs/sipb/project/sandbox/golem/db-3.0.55/docs/api_c/env_open.html
#include <db.h>
int DBENV->open(DB_ENV *, char *db_home, char *db_config[], u_int32_t flags, int mode);
Description
The DBENV->open function is the interface for opening the Berkeley DB environment. It provides a structure for creating a consistent environment for processes using one or more of the features of Berkeley DB.