This method is only useful for the rare Berkeley DB application that does not control its umask value.

Normally, if Berkeley DB applications set their umask appropriately, all processes in the application suite obtain read permission on the log files created by any process in the application suite. However, if the Berkeley DB application is a library, a process using the library might set its umask to a value preventing other processes in the application suite from reading the log files it creates. In this rare case, the DB_ENV->set_lg_filemode() method can be used to set the mode of created log files to an absolute value.