#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.