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+<li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
+</ul>
+</li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer’s Certificate of Origin 1.1</a></li>
+</ul>
+</li>
+</ul>
+<ul class="current">
+<li class="toctree-l1 current"><a class="reference internal" href="index.html">General Topics</a><ul class="current">
+<li class="toctree-l2"><a class="reference internal" href="urls.html">CodeIgniter URLs</a></li>
+<li class="toctree-l2"><a class="reference internal" href="controllers.html">Controllers</a></li>
+<li class="toctree-l2"><a class="reference internal" href="reserved_names.html">Reserved Names</a></li>
+<li class="toctree-l2"><a class="reference internal" href="views.html">Views</a></li>
+<li class="toctree-l2"><a class="reference internal" href="models.html">Models</a></li>
+<li class="toctree-l2"><a class="reference internal" href="helpers.html">Helpers</a></li>
+<li class="toctree-l2"><a class="reference internal" href="libraries.html">Using CodeIgniter Libraries</a></li>
+<li class="toctree-l2"><a class="reference internal" href="creating_libraries.html">Creating Libraries</a></li>
+<li class="toctree-l2"><a class="reference internal" href="drivers.html">Using CodeIgniter Drivers</a></li>
+<li class="toctree-l2"><a class="reference internal" href="creating_drivers.html">Creating Drivers</a></li>
+<li class="toctree-l2"><a class="reference internal" href="core_classes.html">Creating Core System Classes</a></li>
+<li class="toctree-l2"><a class="reference internal" href="ancillary_classes.html">Creating Ancillary Classes</a></li>
+<li class="toctree-l2"><a class="reference internal" href="hooks.html">Hooks - Extending the Framework Core</a></li>
+<li class="toctree-l2"><a class="reference internal" href="autoloader.html">Auto-loading Resources</a></li>
+<li class="toctree-l2 current"><a class="current reference internal" href="#">Common Functions</a></li>
+<li class="toctree-l2"><a class="reference internal" href="compatibility_functions.html">Compatibility Functions</a></li>
+<li class="toctree-l2"><a class="reference internal" href="routing.html">URI Routing</a></li>
+<li class="toctree-l2"><a class="reference internal" href="errors.html">Error Handling</a></li>
+<li class="toctree-l2"><a class="reference internal" href="caching.html">Caching</a></li>
+<li class="toctree-l2"><a class="reference internal" href="profiling.html">Profiling Your Application</a></li>
+<li class="toctree-l2"><a class="reference internal" href="cli.html">Running via the CLI</a></li>
+<li class="toctree-l2"><a class="reference internal" href="managing_apps.html">Managing your Applications</a></li>
+<li class="toctree-l2"><a class="reference internal" href="environments.html">Handling Multiple Environments</a></li>
+<li class="toctree-l2"><a class="reference internal" href="alternative_php.html">Alternate PHP Syntax for View Files</a></li>
+<li class="toctree-l2"><a class="reference internal" href="security.html">Security</a></li>
+<li class="toctree-l2"><a class="reference internal" href="styleguide.html">PHP Style Guide</a></li>
+</ul>
+</li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../libraries/index.html">Libraries</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/benchmark.html">Benchmarking Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/caching.html">Caching Driver</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/calendar.html">Calendaring Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/cart.html">Shopping Cart Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/config.html">Config Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/email.html">Email Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/encrypt.html">Encrypt Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/encryption.html">Encryption Library</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/file_uploading.html">File Uploading Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/form_validation.html">Form Validation</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/ftp.html">FTP Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/image_lib.html">Image Manipulation Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/input.html">Input Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/javascript.html">Javascript Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/language.html">Language Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/loader.html">Loader Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/migration.html">Migrations Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/output.html">Output Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/pagination.html">Pagination Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/parser.html">Template Parser Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/security.html">Security Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/sessions.html">Session Library</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/table.html">HTML Table Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/trackback.html">Trackback Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/typography.html">Typography Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/unit_testing.html">Unit Testing Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/uri.html">URI Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/user_agent.html">User Agent Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../libraries/zip.html">Zip Encoding Class</a></li>
+</ul>
+</li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../database/index.html">Database Reference</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="../database/examples.html">Quick Start: Usage Examples</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/configuration.html">Database Configuration</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/connecting.html">Connecting to a Database</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/queries.html">Running Queries</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/results.html">Generating Query Results</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/helpers.html">Query Helper Functions</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/query_builder.html">Query Builder Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/transactions.html">Transactions</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/metadata.html">Getting MetaData</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/call_function.html">Custom Function Calls</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/caching.html">Query Caching</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/forge.html">Database Manipulation with Database Forge</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/utilities.html">Database Utilities Class</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../database/db_driver_reference.html">Database Driver Reference</a></li>
+</ul>
+</li>
+</ul>
+<ul>
+<li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
+<li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
+</ul>
+</li>
+</ul>
+
+
+
+ </div>
+ &nbsp;
+ </nav>
+
+ <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
+
+
+ <nav class="wy-nav-top" role="navigation" aria-label="top navigation">
+ <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
+ <a href="../index.html">CodeIgniter</a>
+ </nav>
+
+
+
+ <div class="wy-nav-content">
+ <div class="rst-content">
+ <div role="navigation" aria-label="breadcrumbs navigation">
+ <ul class="wy-breadcrumbs">
+ <li><a href="../index.html">Docs</a> &raquo;</li>
+
+ <li><a href="index.html">General Topics</a> &raquo;</li>
+
+ <li>Common Functions</li>
+ <li class="wy-breadcrumbs-aside">
+
+ </li>
+ <div style="float:right;margin-left:5px;" id="closeMe">
+ <img title="Classic Layout" alt="classic layout" src="data:image/gif;base64,R0lGODlhFAAUAJEAAAAAADMzM////wAAACH5BAUUAAIALAAAAAAUABQAAAImlI+py+0PU5gRBRDM3DxbWoXis42X13USOLauUIqnlsaH/eY6UwAAOw==" />
+ </div>
+ </ul>
+ <hr/>
+</div>
+ <div role="main" class="document">
+
+ <div class="section" id="common-functions">
+<h1>Common Functions<a class="headerlink" href="#common-functions" title="Permalink to this headline">¶</a></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>
+<div class="custom-index container"></div><dl class="function">
+<dt id="is_php">
+<code class="descname">is_php</code><span class="sig-paren">(</span><em>$version</em><span class="sig-paren">)</span><a class="headerlink" href="#is_php" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$version</strong> (<em>string</em>) – Version number</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">TRUE if the running PHP version is at least the one specified or FALSE if not</p>
+</td>
+</tr>
+<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">bool</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Determines if the PHP version being used is greater than the
+supplied version number.</p>
+<p>Example:</p>
+<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span><span class="nx">is_php</span><span class="p">(</span><span class="s1">&#39;5.3&#39;</span><span class="p">))</span>
+<span class="p">{</span>
+ <span class="nv">$str</span> <span class="o">=</span> <span class="nb">quoted_printable_encode</span><span class="p">(</span><span class="nv">$str</span><span class="p">);</span>
+<span class="p">}</span>
+</pre></div>
+</div>
+<p>Returns boolean TRUE if the installed version of PHP is equal to or
+greater than the supplied version number. Returns FALSE if the installed
+version of PHP is lower than the supplied version number.</p>
+</dd></dl>
+
+<dl class="function">
+<dt id="is_really_writable">
+<code class="descname">is_really_writable</code><span class="sig-paren">(</span><em>$file</em><span class="sig-paren">)</span><a class="headerlink" href="#is_really_writable" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$file</strong> (<em>string</em>) – File path</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">TRUE if the path is writable, FALSE if not</p>
+</td>
+</tr>
+<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">bool</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p><code class="docutils literal"><span class="pre">is_writable()</span></code> 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.</p>
+<p>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>
+<p>Example:</p>
+<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span><span class="nx">is_really_writable</span><span class="p">(</span><span class="s1">&#39;file.txt&#39;</span><span class="p">))</span>
+<span class="p">{</span>
+ <span class="k">echo</span> <span class="s2">&quot;I could write to this if I wanted to&quot;</span><span class="p">;</span>
+<span class="p">}</span>
+<span class="k">else</span>
+<span class="p">{</span>
+ <span class="k">echo</span> <span class="s2">&quot;File is not writable&quot;</span><span class="p">;</span>
+<span class="p">}</span>
+</pre></div>
+</div>
+<div class="admonition note">
+<p class="first admonition-title">Note</p>
+<p class="last">See also <a class="reference external" href="https://bugs.php.net/bug.php?id=54709">PHP bug #54709</a> for more info.</p>
+</div>
+</dd></dl>
+
+<dl class="function">
+<dt id="config_item">
+<code class="descname">config_item</code><span class="sig-paren">(</span><em>$key</em><span class="sig-paren">)</span><a class="headerlink" href="#config_item" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$key</strong> (<em>string</em>) – Config item key</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Configuration key value or NULL if not found</p>
+</td>
+</tr>
+<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">mixed</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p>The <a class="reference internal" href="../libraries/config.html"><span class="doc">Config Library</span></a> is the preferred way of
+accessing configuration information, however <code class="docutils literal"><span class="pre">config_item()</span></code> can be used
+to retrieve single keys. See <a class="reference internal" href="../libraries/config.html"><span class="doc">Config Library</span></a>
+documentation for more information.</p>
+</dd></dl>
+
+<dl class="function">
+<dt id="set_status_header">
+<code class="descname">set_status_header</code><span class="sig-paren">(</span><em>$code</em><span class="optional">[</span>, <em>$text = ''</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#set_status_header" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$code</strong> (<em>int</em>) – HTTP Response status code</li>
+<li><strong>$text</strong> (<em>string</em>) – A custom message to set with the status code</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">void</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Permits you to manually set a server status header. Example:</p>
+<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nx">set_status_header</span><span class="p">(</span><span class="mi">401</span><span class="p">);</span>
+<span class="c1">// Sets the header as: Unauthorized</span>
+</pre></div>
+</div>
+<p><a class="reference external" href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html">See here</a> for
+a full list of headers.</p>
+</dd></dl>
+
+<dl class="function">
+<dt id="remove_invisible_characters">
+<code class="descname">remove_invisible_characters</code><span class="sig-paren">(</span><em>$str</em><span class="optional">[</span>, <em>$url_encoded = TRUE</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#remove_invisible_characters" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$str</strong> (<em>string</em>) – Input string</li>
+<li><strong>$url_encoded</strong> (<em>bool</em>) – Whether to remove URL-encoded characters as well</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Sanitized string</p>
+</td>
+</tr>
+<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">string</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p>This function prevents inserting NULL characters between ASCII
+characters, like Java\0script.</p>
+<p>Example:</p>
+<div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nx">remove_invisible_characters</span><span class="p">(</span><span class="s1">&#39;Java\\0script&#39;</span><span class="p">);</span>
+<span class="c1">// Returns: &#39;Javascript&#39;</span>
+</pre></div>
+</div>
+</dd></dl>
+
+<dl class="function">
+<dt id="html_escape">
+<code class="descname">html_escape</code><span class="sig-paren">(</span><em>$var</em><span class="sig-paren">)</span><a class="headerlink" href="#html_escape" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$var</strong> (<em>mixed</em>) – Variable to escape (string or array)</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">HTML escaped string(s)</p>
+</td>
+</tr>
+<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">mixed</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p>This function acts as an alias for PHP’s native <code class="docutils literal"><span class="pre">htmlspecialchars()</span></code>
+function, with the advantage of being able to accept an array of strings.</p>
+<p>It is useful in preventing Cross Site Scripting (XSS).</p>
+</dd></dl>
+
+<dl class="function">
+<dt id="get_mimes">
+<code class="descname">get_mimes</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#get_mimes" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">An associative array of file types</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">array</td>
+</tr>
+</tbody>
+</table>
+<p>This function returns a <em>reference</em> to the MIMEs array from
+<em>application/config/mimes.php</em>.</p>
+</dd></dl>
+
+<dl class="function">
+<dt id="is_https">
+<code class="descname">is_https</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#is_https" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">TRUE if currently using HTTP-over-SSL, FALSE if not</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">bool</td>
+</tr>
+</tbody>
+</table>
+<p>Returns TRUE if a secure (HTTPS) connection is used and FALSE
+in any other case (including non-HTTP requests).</p>
+</dd></dl>
+
+<dl class="function">
+<dt id="is_cli">
+<code class="descname">is_cli</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#is_cli" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">TRUE if currently running under CLI, FALSE otherwise</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">bool</td>
+</tr>
+</tbody>
+</table>
+<p>Returns TRUE if the application is run through the command line
+and FALSE if not.</p>
+<div class="admonition note">
+<p class="first admonition-title">Note</p>
+<p class="last">This function checks both if the <code class="docutils literal"><span class="pre">PHP_SAPI</span></code> value is ‘cli’
+or if the <code class="docutils literal"><span class="pre">STDIN</span></code> constant is defined.</p>
+</div>
+</dd></dl>
+
+<dl class="function">
+<dt id="function_usable">
+<code class="descname">function_usable</code><span class="sig-paren">(</span><em>$function_name</em><span class="sig-paren">)</span><a class="headerlink" href="#function_usable" title="Permalink to this definition">¶</a></dt>
+<dd><table class="docutils field-list" frame="void" rules="none">
+<col class="field-name" />
+<col class="field-body" />
+<tbody valign="top">
+<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
+<li><strong>$function_name</strong> (<em>string</em>) – Function name</li>
+</ul>
+</td>
+</tr>
+<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">TRUE if the function can be used, FALSE if not</p>
+</td>
+</tr>
+<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">bool</p>
+</td>
+</tr>
+</tbody>
+</table>
+<p>Returns TRUE if a function exists and is usable, FALSE otherwise.</p>
+<p>This function runs a <code class="docutils literal"><span class="pre">function_exists()</span></code> check and if the
+<cite>Suhosin extension &lt;http://www.hardened-php.net/suhosin/&gt;</cite> is loaded,
+checks if it doesn’t disable the function being checked.</p>
+<p>It is useful if you want to check for the availability of functions
+such as <code class="docutils literal"><span class="pre">eval()</span></code> and <code class="docutils literal"><span class="pre">exec()</span></code>, which are dangerous and might be
+disabled on servers with highly restrictive security policies.</p>
+<div class="admonition note">
+<p class="first admonition-title">Note</p>
+<p class="last">This function was introduced because Suhosin terminated
+script execution, but this turned out to be a bug. A fix
+has been available for some time (version 0.9.34), but is
+unfortunately not released yet.</p>
+</div>
+</dd></dl>
+
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