# DbMpoolFile::set_clear_len |

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    #include <db_cxx.h>

    int
    DbMpoolFile::set(u_int32_t len);

# Description

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 being specified to DbMpoolFile::get. If no value is specified, or len is 0, the entire page is cleared.

The DbMpoolFile::set_clear_len method configures a file in the memory pool, not only operations performed using the specified DbMpoolFile handle.

The DbMpoolFile::set_clear_len interface may not be called after the DbMpoolFile::open interface is called. If the file is already open in the memory pool 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.

# Errors

The DbMpoolFile::set_clear_len method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods. If a catastrophic error has occurred, the DbMpoolFile::set_clear_len method may fail and either return DB_RUNRECOVERY or throw a DbRunRecoveryException, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

DbEnv, DbMpoolFile

# See Also

Memory Pools and Related Methods`

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