libdb/docs/api_reference/C/db_env_set_func_seek.html
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<h2 class="title" style="clear: both"><a id="db_env_set_func_seek"></a>db_env_set_func_seek</h2>
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<pre class="programlisting">#include &lt;db.h&gt;
int
db_env_set_func_seek(int (*func_seek)(int fd, off_t offset, int whence)); </pre>
<p>
The Berkeley DB library requires the ability to specify that a
subsequent read from or write to a file will occur at a specific
location in that file.
</p>
<p>
The <code class="function">db_env_set_func_seek()</code> function configures all operations performed by
a process and all of its threads of control, not operations confined
to a single database environment.
</p>
<p>
Although the <code class="function">db_env_set_func_seek()</code> function may be called at any time
during the life of the application, it should normally be called
before making calls to the <a class="xref" href="envcreate.html" title="db_env_create">db_env_create</a> or
<a class="xref" href="dbcreate.html" title="db_create">db_create</a> methods.
</p>
<p>
The <code class="function">db_env_set_func_seek()</code> <span>
function returns a non-zero error value on failure and 0 on success.
</span>
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<h3 class="title"><a id="idp63684616"></a>Parameters</h3>
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<h4 class="title"><a id="idp63684808"></a>func_seek</h4>
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<p>
The <span class="bold"><strong>func_seek</strong></span> parameter is the
function which seeks to a specific location in a file.
</p>
<p>
The <span class="bold"><strong>fd</strong></span> parameter is an open file
descriptor on the file.
</p>
<p>
The <span class="bold"><strong>seek</strong></span> function must cause a
subsequent read from or write to the file to occur at the byte offset
specified by the <span class="bold"><strong>offset</strong></span> parameter.
</p>
<p>
The <span class="bold"><strong>whence</strong></span> parameter specifies where
in the file the byte offset is relative to, as described by the
IEEE/ANSI Std 1003.1 (POSIX) <span class="bold"><strong>lseek</strong></span>
system call.
</p>
<p>
The <span class="bold"><strong>func_seek</strong></span> function must return
the value of <span class="bold"><strong>errno</strong></span> on failure and 0
on success.
</p>
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<h3 class="title"><a id="idp63682440"></a>See Also</h3>
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<a href="../../programmer_reference/program_runtime.html" class="olink">Run-time configuration</a>
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