#include <db_cxx.h>
 
DB_ENV->get_backup_callbacks(
        int (**open_func)(DB_ENV *, const char *dbname, 
                          const char *target, void **handle),
        int (**write_func)(DB_ENV *, u_int32_t offset_gbytes, 
                           u_int32_t offset_bytes, u_int32_t size, 
                           u_int8_t *buf, void *handle),
        int (**close_func)(DB_ENV *, const char *dbname, void *handle)); 
      
         The DbEnv::get_backup_callbacks() method
         retrieves the three callback functions which can be used by the
         DbEnv::backup()
         or
         DbEnv::dbbackup()
         methods to override their default behavior. These callbacks are
         configured using the 
         DbEnv::set_backup_callbacks()
         method.
     
         The DbEnv::get_backup_callbacks() method may
         be called at any time during the life of the application.
     
         The DbEnv::get_backup_callbacks() 
            
            
                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 open_func parameter is the function used when a target location is opened during a backup.