#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.