# DbEnv::set_data_dir

`

###

    #include <db_cxx.h>

    int
    DbEnv::set_data_dir(const char *dir);

# Description

Set the path of a directory to be used as the location of the access method database files. Paths specified to the Db::open function will be searched relative to this path. Paths set using this interface are additive, and specifying more than one will result in each specified directory being searched for database files. If any directories are specified, created database files will always be created in the first path specified.

If no database directories are specified, database files can only exist in the environment home directory. See Berkeley DB File Naming for more information.

For the greatest degree of recoverability from system or application failure, database files and log files should be located on separate physical devices.

The DbEnv::set_data_dir interface may only be used to configure Berkeley DB before the DbEnv::open interface is called.

The DbEnv::set_data_dir 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.

The database environment's data directory may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_data_dir", one or more whitespace characters, and the directory name. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.

# Errors

EINVAL
  An invalid flag value or parameter was specified.

  Called after DbEnv::open was called.

### Class

DbEnv

# See Also

DbEnv::close, DbEnv::open, DbEnv::remove, DbEnv::err, DbEnv::strerror, DbEnv::version, DbEnv::set_cachesize, DbEnv::set_errcall, DbEnv::set_errfile, DbEnv::set_error_stream, DbEnv::set_errpfx, DbEnv::set_flags, DbEnv::set_mutexlocks, DbEnv::set_paniccall, and DbEnv::set_verbose.`

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