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<th width="60%" align="center">Chapter 14.
Binary Large Objects
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<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="dbstream"></a>Dbc::db_stream()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db_cxx.h>
int
Dbc::db_stream(DbStream **dbs, u_int32_t flags); </pre>
<p>
The <code class="methodname">Dbc::db_stream()</code> method points to a
key/value pair where the data item is a binary large object
(BLOB). Use the <span class="bold"><strong>flags</strong></span> parameter
to indicate whether the stream is to be opened for reading, or for
reading and writing.
</p>
<p>
Once the stream is opened, you read it using <a class="xref" href="dbstream_read.html" title="DbStream::read()">DbStream::read()</a>, and
you write to it using <a class="xref" href="dbstream_write.html" title="DbStream::write()">DbStream::write()</a>.
</p>
<p>
Close this stream using <a class="xref" href="dbstream_close.html" title="DbStream::close()">DbStream::close()</a>.
</p>
<p>
If the data item is not a BLOB, this method returns an error.
</p>
<p>
Unless otherwise specified, the
<code class="methodname">Dbc::db_stream()</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">
<div>
<div>
<h3 class="title"><a id="idp5316760"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp5317360"></a>dbs</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>dbs</strong></span>
parameter references memory into which is copied the newly
opened stream.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp5306328"></a>flags</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>flags</strong></span> parameter
must be set by bitwise inclusively
<span class="bold"><strong>OR</strong></span>'ing together one or more of
the following values:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p><a id="blobs_DB_STREAM_READ"></a>
<code class="literal">DB_STREAM_READ</code>
</p>
<p>
Indicates that the stream is to be opened for
read-only access.
</p>
</li>
<li>
<p><a id="blobs_DB_STREAM_WRITE"></a>
<code class="literal">DB_STREAM_WRITE</code>
</p>
<p>
Indicates that the stream is to be opened for
read write access. The stream is sync'd to disc when
the stream is closed.
</p>
</li>
<li>
<p><a id="blobs_DB_STREAM_SYNC_WRITE"></a>
<code class="literal">DB_STREAM_SYNC_WRITE</code>
</p>
<p>
Indicates that the stream is to be opened for
read and write access. The stream is sync'd to disc after
each write, instead of when the stream is closed.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp5324952"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">Dbc::db_stream()</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="idp5335728"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
If the data item is not a BLOB; or if an invalid flag or
parameter is specified.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp5328168"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="dbc.html" title="Chapter 3. The Dbc Handle">Dbc</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp5331592"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a class="xref" href="blob.html#bloblist" title="BLOBs and Related Methods">BLOBs and Related Methods</a>
</p>
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