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<h2 class="title" style="clear: both"><a id="envset_region_dir"></a>
<span>DbEnv::set_region_dir()</span>
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<pre class="programlisting">#include <db_cxx.h>
int
DbEnv::set_region_dir(const char *dir); </pre>
<p>
The path of a directory to be used as the location of disk-backed
region files. Region files created by the Memory Pool subsystem
will be created in this directory.
</p>
<p>
If no region directory is specified, region files are created in
the environment home directory. See
<a href="../../programmer_reference/env_naming.html" class="olink">Berkeley DB File Naming</a>
for more information.
</p>
<p>
The database environment's region directory may also be
configured using the environment's <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file. The syntax
of the entry in that file is a single line with the string
"set_region_dir", one or more whitespace characters, and the directory
name. Because the <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file is read when the database
environment is opened, it will silently overrule configuration
done before that time. Note that if you use this method for your
application, and you also want to use the various utilities like
<a class="xref" href="db_recover.html" title="db_recover">db_recover</a>,
then you should set create a <a href="../../programmer_reference/env_db_config.html#env_db_config.DB_CONFIG" class="olink">DB_CONFIG</a> file and set
the "set_region_dir" parameter in it.
</p>
<p>
The <code class="methodname">DbEnv::set_region_dir()</code> method configures operations
performed using the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>
handle, not all operations performed on the underlying database
environment.
</p>
<p>
The <code class="methodname">DbEnv::set_region_dir()</code> method may not be called after the
<a class="xref" href="envopen.html" title="DbEnv::open()">
<span>DbEnv::open()</span>
</a> method is called.
If the database environment already exists when
<a class="xref" href="envopen.html" title="DbEnv::open()">
<span>DbEnv::open()</span>
</a> is called, the
information specified to <code class="methodname">DbEnv::set_region_dir()</code> must be consistent with
the existing environment or corruption can occur.
</p>
<p>
The <code class="methodname">DbEnv::set_region_dir()</code> <span>
<span>
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.
</span>
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h3 class="title"><a id="idm139755612206688"></a>Parameters</h3>
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<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idm139755612159536"></a>dir</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>dir</strong></span> parameter is the
directory used to store the region files. This
directory must currently exist at environment open time.
</p>
<p>
When using a Unicode build on Windows (the default), the
<span class="bold"><strong>dir</strong></span> argument will be
interpreted as a UTF-8 string, which is equivalent to
ASCII for Latin characters.
</p>
</div>
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<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
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<h3 class="title"><a id="idm139755612168352"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DbEnv::set_region_dir()</code> <span>
<span>
method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a>
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors:
</span>
</span>
</p>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idm139755612128800"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If the method was called after <a class="xref" href="envopen.html" title="DbEnv::open()">
<span>DbEnv::open()</span>
</a>
was called; or if an invalid flag value or parameter was specified.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idm139755612134640"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>,
<a class="link" href="memp.html" title="Chapter 9. The DbMpoolFile Handle">DbMpoolFile</a>
</p>
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<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idm139755612155184"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a>,
<a class="xref" href="envget_region_dir.html" title="DbEnv::get_region_dir()">
<span>DbEnv::get_region_dir()</span>
</a>
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