#include <db.h> int DB_MPOOLFILE->get_pgcookie(DB_MPOOLFILE *mpf, DBT *dbt);
        The DB_MPOOLFILE->get_pgcookie() method returns the byte string provided
        to the functions registered to do input or output processing of the file's pages as they are
        read from or written to, the backing filesystem store. This byte string is configured using
        the DB_MPOOLFILE->set_pgcookie() method.
    
         The DB_MPOOLFILE->get_pgcookie() method may be called at any time
         during the life of the application.
    
         The DB_MPOOLFILE->get_pgcookie() 
            
                  method returns a non-zero error value on failure and 0 on success.