EVOLUTION-NINJA

Edit File: common_functions.html

<!DOCTYPE html>

 <html class="no-js" lang="en" > 
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  
  <title>Common Functions &mdash; CodeIgniter 3.1.5 documentation</title>

</head>

<div id="nav">
  <div id="nav_inner">
    
    
    
      <div id="pulldown-menu" class="ciNav">
        <ul>
<li class="toctree-l1"><a class="reference internal" href="welcome.html">Welcome to CodeIgniter</a><ul class="simple">
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
<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&#8217;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>
    
      
  </div>
</div>
<div id="nav2">
  <a href="#" id="openToc">
    <img src="data:image/jpeg;base64,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" title="Toggle Table of Contents" alt="Toggle Table of Contents" />
  </a>
</div>

<nav data-toggle="wy-nav-shift" class="wy-nav-side">
      <div class="wy-side-nav-search">
        
          <a href="../index.html" class="fa fa-home"> CodeIgniter</a>
        
        
<div role="search">
  <form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
    <input type="text" name="q" placeholder="Search docs" />
    <input type="hidden" name="check_keywords" value="yes" />
    <input type="hidden" name="area" value="default" />
  </form>
</div>
      </div>

<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
        
          
          
              <ul>
<li class="toctree-l1"><a class="reference internal" href="welcome.html">Welcome to CodeIgniter</a><ul class="simple">
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
<li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
<li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
</ul>
</li>
</ul>
<ul>
<li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
<li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
<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&#8217;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>

<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">
<tt class="descname">is_php</tt><big>(</big><em>$version</em><big>)</big><a class="headerlink" href="#is_php" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$version</strong> (<em>string</em>) &#8211; 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">
<tt class="descname">is_really_writable</tt><big>(</big><em>$file</em><big>)</big><a class="headerlink" href="#is_really_writable" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$file</strong> (<em>string</em>) &#8211; 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><tt class="docutils literal"><span class="pre">is_writable()</span></tt> returns TRUE on Windows servers when you really can&#8217;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">
<tt class="descname">config_item</tt><big>(</big><em>$key</em><big>)</big><a class="headerlink" href="#config_item" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$key</strong> (<em>string</em>) &#8211; 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"><em>Config Library</em></a> is the preferred way of
accessing configuration information, however <tt class="docutils literal"><span class="pre">config_item()</span></tt> can be used
to retrieve single keys. See <a class="reference internal" href="../libraries/config.html"><em>Config Library</em></a>
documentation for more information.</p>
</dd></dl>

<dl class="function">
<dt id="set_status_header">
<tt class="descname">set_status_header</tt><big>(</big><em>$code</em><span class="optional">[</span>, <em>$text = ''</em><span class="optional">]</span><big>)</big><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>$code</strong> (<em>int</em>) &#8211; HTTP Response status code</li>
<li><strong>$text</strong> (<em>string</em>) &#8211; 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">
<tt class="descname">remove_invisible_characters</tt><big>(</big><em>$str</em><span class="optional">[</span>, <em>$url_encoded = TRUE</em><span class="optional">]</span><big>)</big><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>$str</strong> (<em>string</em>) &#8211; Input string</li>
<li><strong>$url_encoded</strong> (<em>bool</em>) &#8211; 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">
<tt class="descname">html_escape</tt><big>(</big><em>$var</em><big>)</big><a class="headerlink" href="#html_escape" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$var</strong> (<em>mixed</em>) &#8211; 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&#8217;s native <tt class="docutils literal"><span class="pre">htmlspecialchars()</span></tt>
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">
<tt class="descname">get_mimes</tt><big>(</big><big>)</big><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">
<tt class="descname">is_https</tt><big>(</big><big>)</big><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">
<tt class="descname">is_cli</tt><big>(</big><big>)</big><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 <tt class="docutils literal"><span class="pre">PHP_SAPI</span></tt> value is &#8216;cli&#8217;
or if the <tt class="docutils literal"><span class="pre">STDIN</span></tt> constant is defined.</p>
</div>
</dd></dl>

<dl class="function">
<dt id="function_usable">
<tt class="descname">function_usable</tt><big>(</big><em>$function_name</em><big>)</big><a class="headerlink" href="#function_usable" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$function_name</strong> (<em>string</em>) &#8211; 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 <tt class="docutils literal"><span class="pre">function_exists()</span></tt> check and if the
<cite>Suhosin extension &lt;http://www.hardened-php.net/suhosin/&gt;</cite> is loaded,
checks if it doesn&#8217;t disable the function being checked.</p>
<p>It is useful if you want to check for the availability of functions
such as <tt class="docutils literal"><span class="pre">eval()</span></tt> and <tt class="docutils literal"><span class="pre">exec()</span></tt>, 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>

</div>

</div>
          <footer>
  
    <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
      
        <a href="compatibility_functions.html" class="btn btn-neutral float-right" title="Compatibility Functions">Next <span class="fa fa-arrow-circle-right"></span></a>
      
      
        <a href="autoloader.html" class="btn btn-neutral" title="Auto-loading Resources"><span class="fa fa-arrow-circle-left"></span> Previous</a>
      
    </div>

<hr/>

Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
  
</footer>
        </div>
      </div>

</section>

</div>

</body>
</html>