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<h1>Common Functions</h1>

<p>CodeIgniter uses a few functions for its operation that are globally defined, and are available to you at any point. These do not require loading any libraries or helpers.</p>
<h2>is_really_writable('<var>path/to/file</var>')</h2>
<p>is_writable() returns TRUE on Windows servers when you really can't write to the file as the OS reports to PHP as FALSE only if the read-only attribute is marked. This function determines if a file is actually writable by attempting to write to it first. Generally only recommended on platforms where this information may be unreliable.</p>
<code>if (is_really_writable('file.txt'))<br />
{<br />
      echo &quot;I could write to this if I wanted to&quot;;<br />
}<br />
else<br />
{<br />
      echo &quot;File is not writable&quot;;<br />
}</code>
<h2>config_item('<var>item_key</var>')</h2>
<p>The <a href="../libraries/config.html">Config library</a> is the preferred way of accessing configuration information, however config_item() can be used to retrieve single keys. See Config library documentation for more information.</p>
<h2>show_error('<var>message</var>'), show_404('<var>page</var>'), log_message('<var>level</var>', '<samp>message</samp>')</h2>
<p>These are each outlined on the <a href="errors.html">Error Handling</a> page.</p>
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