#include <db_cxx.h> int DbMpoolFile::get_pgcookie(DBT *dbt);
        The DbMpoolFile::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 DbMpoolFile::set_pgcookie() method.
    
         The DbMpoolFile::get_pgcookie() method may be called at any time
         during the life of the application.
    
         The DbMpoolFile::get_pgcookie() 
            
            
                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.