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<title>Berkeley DB: DbEnv::set_data_dir</title>
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<h3>DbEnv::set_data_dir</h3>
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<h3><pre>
#include <db_cxx.h>
<p>
int
DbEnv::set_data_dir(const char *dir);
<p>
int
DbEnv::get_data_dirs(const char ***dirpp);
</pre></h3>
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<h3>Description: DbEnv::set_data_dir</h3>
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<p>Set the path of a directory to be used as the location of the access
method database files. Paths specified to the <a href="../api_cxx/db_open.html">Db::open</a> function
will be searched relative to this path. Paths set using this method
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.</p>
<p>If no database directories are specified, database files can exist only
in the environment home directory. See <a href="../ref/env/naming.html">Berkeley DB File Naming</a> for more information.</p>
<p>For the greatest degree of recoverability from system or application
failure, database files and log files should be located on separate
physical devices.</p>
<p>The database environment's data directories may also be set using the environment's
<b>DB_CONFIG</b> 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.
</p>
<p>The DbEnv::set_data_dir method configures operations performed using the specified
<a href="../api_cxx/env_class.html">DbEnv</a> handle, not all operations performed on the underlying
database environment.</p>
<p>The DbEnv::set_data_dir method may not be called after the <a href="../api_cxx/env_open.html">DbEnv::open</a> method is
called.
If the database environment already exists when
<a href="../api_cxx/env_open.html">DbEnv::open</a> is called, the information specified to DbEnv::set_data_dir
must be consistent with the existing environment or corruption can
occur.</p>
<p>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.
</p>
<h3>Parameters</h3>
<p><dl compact>
<p><dt><b>dir</b><dd>
The <b>dir</b> parameter is a directory to be used as a location for
database files.
</dl>
<h3>Errors</h3>
<p>The DbEnv::set_data_dir method
may fail and throw
<a href="../api_cxx/except_class.html">DbException</a>,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:</p>
<p><dl compact>
<p><dt>EINVAL<dd>If the method was called after <a href="../api_cxx/env_open.html">DbEnv::open</a> was called; or if an
invalid flag value or parameter was specified.
</dl>
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<h3>Description: DbEnv::get_data_dirs</h3>
<p>The DbEnv::get_data_dirs method returns the NULL-terminated
array of directories.</p>
<p>The DbEnv::get_data_dirs method may be called at any time during the life of the
application.</p>
<p>The DbEnv::get_data_dirs 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.
</p>
<h3>Parameters</h3>
<p><dl compact>
<p><dt><b>dirpp</b><dd>
The DbEnv::get_data_dirs method returns a reference to the
NULL-terminated
array of directories in <b>dirpp</b>.
</dl>
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<h3>Class</h3>
<a href="../api_cxx/env_class.html">DbEnv</a>
<h3>See Also</h3>
<a href="../api_cxx/env_list.html">Database Environments and Related Methods</a>
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