This is libdbm, a relatively ancient db library that you could find on most unixes. In the 90s you might target dbm for your portable Unix application because

This is libdbm, a relatively ancient db library that you could find on most unixes. In the 90s you might target dbm for your portable Unix application because you could reasonably expect it to be implemented on your platform. It lost a lot of share to gdbm and sleepycat's BerkeleyDB, both of which I consider its successor. Of course all of this is now sqlite3.