#include <db.h> int DB_MPOOLFILE->set_clear_len(DB_MPOOLFILE *mpf, u_int32_t len);
         The DB_MPOOLFILE->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 DB_MPOOLFILE->get().  If no
         clear length is specified, the entire page is cleared when it is
         created.
    
         The DB_MPOOLFILE->set_clear_len() method configures a file in the
         cache, not only operations performed using the specified 
         DB_MPOOLFILE  handle.
    
         The DB_MPOOLFILE->set_clear_len() method may not be called after the
         DB_MPOOLFILE->open() 
         method is called. If the file is already open in the cache when
         DB_MPOOLFILE->open()  is
         called, the information specified to DB_MPOOLFILE->set_clear_len()
         must be consistent with the existing file or an error will be returned.
    
         The DB_MPOOLFILE->set_clear_len() 
            
                  method returns a non-zero error value on failure and 0 on success.