#include <db_cxx.h> int DbMpoolFile::set_clear_len(u_int32_t len);
         The DbMpoolFile::set_clear_len() method sets the number of initial
         bytes in a page that should be set to nul when the page is created as
         a result of the 
         DB_MPOOL_CREATE 
         or DB_MPOOL_NEW  
         flags specified to DbMpoolFile::get().  If no
         clear length is specified, the entire page is cleared when it is
         created.
    
         The DbMpoolFile::set_clear_len() method configures a file in the
         cache, not only operations performed using the specified 
         DbMpoolFile  handle.
    
         The DbMpoolFile::set_clear_len() method may not be called after the
         DbMpoolFile::open() 
         method is called. If the file is already open in the cache when
         DbMpoolFile::open()  is
         called, the information specified to DbMpoolFile::set_clear_len()
         must be consistent with the existing file or an error will be returned.
    
         The DbMpoolFile::set_clear_len() 
            
            
                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.