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<title>DB_STREAM->write()</title>
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<th colspan="3" align="center">DB_STREAM->write()</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="dbstream_size.html">Prev</a> </td>
<th width="60%" align="center">Chapter 13.
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_write"></a>DB_STREAM->write()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db.h>
int
DB_STREAM->write(DB_STREAM *dbs, DBT *data, db_off_t offset,
u_int32_t flags); </pre>
<p>
The <code class="methodname">DB_STREAM->write()</code> method writes data
to an existing BLOB object in the database. This method writes
data contained in the <a class="link" href="dbt.html" title="Chapter 4. The DBT Handle">DBT</a>
<span class="bold"><strong>data</strong></span> to the BLOB stream. Data is
written into the stream starting at the position indicated by
<span class="bold"><strong>offset</strong></span>. The amount of data
written is determined by the <code class="literal">size</code> field in the
DBT.
</p>
<p>
If this method writes data in the middle of the BLOB, it will
overwrite existing data, instead of shifting it. If this method
writes data to the end of the BLOB, the data is appended to the
existing BLOB. You can determine how large a BLOB is using
<a class="xref" href="dbstream_size.html" title="DB_STREAM->size()">DB_STREAM->size()</a>.
</p>
<p>
To open a stream, use <a class="xref" href="dbstream.html" title="DBC->db_stream()">DBC->db_stream()</a>.
</p>
<p>
Unless otherwise specified, the
<code class="methodname">DB_STREAM->write()</code> <span>
<span>
method returns a non-zero error value on failure and 0 on success.
</span>
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4854344"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4859328"></a>data</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>data</strong></span> parameter is
the <a class="link" href="dbt.html" title="Chapter 4. The DBT Handle">DBT</a> containing the
data to be written to the BLOB. The amount of data to be
written is determined by the DBT's
<code class="literal">size</code> field.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4865264"></a>offset</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>offset</strong></span> parameter
identifies the position in the BLOB where the write
operation will begin.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4852528"></a>flags</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>flags</strong></span> parameter must be set to 0
or the following value:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p><a id="blobstream_DB_STREAM_SYNC_WRITE"></a>
<code class="literal">DB_STREAM_SYNC_WRITE</code>
</p>
<p>
A sync to disk operation is performed on the
stream at the end of the write operation. By
default, the sync is performed only when the
stream is closed using <a class="xref" href="dbstream_close.html" title="DB_STREAM->close()">DB_STREAM->close()</a>. Note that
this flag can also be specified when the stream is
created using <a class="xref" href="dbstream.html" title="DBC->db_stream()">DBC->db_stream()</a>, in which case the sync
behavior becomes the default behavior for this
stream instance.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4873752"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DB_STREAM->write()</code> <span>
<span>
method may fail and 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="idp4860016"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
An invalid flag value or parameter was specified; or if the
stream is read-only; or if the input DBT was
configured with
<a class="link" href="dbt.html#dbt_DB_DBT_PARTIAL">DB_DBT_PARTIAL</a>.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4880040"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="blob.html" title="Chapter 13. Binary Large Objects">DB_STREAM</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4872616"></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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