#include <db.h> int DB_ENV->log_flush(DB_ENV *env, const DB_LSN *lsn);
        The DB_ENV->log_flush() method writes log records to disk.
    
         The DB_ENV->log_flush() 
            
                  method returns a non-zero error value on failure and 0 on success.
            
            
        
    
All log records with DB_LSN values less than or equal to the lsn parameter are written to disk. If lsn is NULL, all records in the log are flushed.
                         The DB_ENV->log_flush() 
            
                 method may fail and return one of the following non-zero errors: