#include <db.h> int DB_MPOOLFILE->get_clear_len(DB_MPOOLFILE *mpf, u_int32_t *lenp);
         The DB_MPOOLFILE->get_clear_len() method returns the bytes to be
         cleared.
    
         The DB_MPOOLFILE->get_clear_len() method may be called at any time
         during the life of the application.
    
         The DB_MPOOLFILE->get_clear_len() 
            
                  method returns a non-zero error value on failure and 0 on success.