#include <db_cxx.h> int DbEnv::log_file(const DbLsn *lsn, char *namep, size_t len);
        The DbEnv::log_file() method maps 
        DbLsn structures to filenames,
         returning the name of the file containing the record named by
         lsn.
    
         This mapping of DbLsn structures to files is needed for database
         administration.  For example, a transaction manager typically records
         the earliest DbLsn 
         needed for restart, and the database administrator may want to archive
         log files to tape when they contain only 
         DbLsn  entries before the
         earliest one needed for restart.
    
         The DbEnv::log_file() 
            
            
                method either returns a non-zero error value or throws an
                exception that encapsulates a non-zero error value on
                failure, and returns 0 on success.
            
        
    
The namep parameter references memory into which the name of the file containing the record named by lsn is copied.
                         The DbEnv::log_file() 
            
            
                method may fail and throw a DbException 
                exception, encapsulating one of the following non-zero errors, or return one
                of the following non-zero errors: