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<title>DB_STREAM->read()</title>
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<th colspan="3" align="center">DB_STREAM->read()</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="dbstream_close.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_read"></a>DB_STREAM->read()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db.h>
int
DB_STREAM->read(DB_STREAM *dbs, DBT *data, db_off_t offset,
u_int32_t size, u_int32_t flags); </pre>
<p>
The <code class="methodname">DB_STREAM->read()</code> method reads
<span class="bold"><strong>size</strong></span> bytes from the BLOB, starting
at <span class="bold"><strong>offset</strong></span>, into the
DBT <span class="bold"><strong>data</strong></span>.
</p>
<p>
The stream is created using <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->read()</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="idp4833328"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4833176"></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> into which you
want to place the data read using this method.
</p>
<p>
Note that the data DBT must be set with one of the
following flags, or this method will return an error:
<a class="link" href="dbt.html#dbt_DB_DBT_MALLOC">DB_DBT_MALLOC</a>,
<a class="link" href="dbt.html#dbt_DB_DBT_REALLOC">DB_DBT_REALLOC</a>,
<a class="link" href="dbt.html#dbt_DB_DBT_USERMEM">DB_DBT_USERMEM</a>, or
<a class="link" href="dbt.html#dbt_DB_DBT_APPMALLOC">DB_DBT_APPMALLOC</a>.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4828760"></a>offset</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>offset</strong></span> parameter
indicates the starting position, in bytes, from the
beginning of the BLOB where you want the read to begin.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4814184"></a>size</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>size</strong></span> parameter
indicates the number of bytes to read.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4834768"></a>flags</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>flags</strong></span> parameter must be set to 0.
</p>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="idp4843664"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DB_STREAM->read()</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="idp4848080"></a>DB_BUFFER_SMALL</h4>
</div>
</div>
</div>
<p>
The DBT provided to this method was not configured
appropriately, and so there is not enough space allocated
for the bytes you are trying to read.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="idp4855560"></a>EINVAL</h4>
</div>
</div>
</div>
<p>
An invalid flag value or parameter was specified; or if the
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="idp4848936"></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="idp4821872"></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>
</div>
</div>
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<a accesskey="u" href="blob.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="dbstream_size.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">DB_STREAM->close() </td>
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<a accesskey="h" href="index.html">Home</a>
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<td width="40%" align="right" valign="top"> DB_STREAM->size()</td>
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