wangsaitao
/
guotianyun-sp-yh


			
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914
							

<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  
  <title>Compatibility Functions &mdash; CodeIgniter 3.1.11 documentation</title>
  

    <link rel="shortcut icon" href="../_static/ci-icon.ico"/>
  

  <link href='https://fonts.googleapis.com/css?family=Lato:400,700,400italic,700italic|Roboto+Slab:400,700|Inconsolata:400,700&subset=latin,cyrillic' rel='stylesheet' type='text/css'>

  
    <link rel="stylesheet" href="../_static/css/citheme.css" type="text/css" />
  

        <link rel="index" title="Index"
              href="../genindex.html"/>
        <link rel="search" title="Search" href="../search.html"/>
    <link rel="top" title="CodeIgniter 3.1.11 documentation" href="../index.html"/>
        <link rel="up" title="General Topics" href="index.html"/>
        <link rel="next" title="URI Routing" href="routing.html"/>
        <link rel="prev" title="Common Functions" href="common_functions.html"/> 

  
  <script src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min.js"></script>

</head>

<body class="wy-body-for-nav" role="document">

  <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></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’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"><a class="reference internal" href="common_functions.html">Common Functions</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">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>

  <div class="wy-grid-for-nav">

    
    <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></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’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"><a class="reference internal" href="common_functions.html">Common Functions</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">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>Compatibility 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="compatibility-functions">
<h1>Compatibility Functions<a class="headerlink" href="#compatibility-functions" title="Permalink to this headline">¶</a></h1>
<p>CodeIgniter provides a set of compatibility functions that enable
you to use functions what are otherwise natively available in PHP,
but only in higher versions or depending on a certain extension.</p>
<p>Being custom implementations, these functions will also have some
set of dependencies on their own, but are still useful if your
PHP setup doesn’t offer them natively.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Much like the <a class="reference internal" href="common_functions.html"><span class="doc">common functions</span></a>, the
compatibility functions are always available, as long as
their dependencies are met.</p>
</div>
<div class="contents local topic" id="contents">
<ul class="simple">
<li><a class="reference internal" href="#password-hashing" id="id7">Password Hashing</a><ul>
<li><a class="reference internal" href="#dependencies" id="id8">Dependencies</a></li>
<li><a class="reference internal" href="#constants" id="id9">Constants</a></li>
<li><a class="reference internal" href="#function-reference" id="id10">Function reference</a></li>
</ul>
</li>
<li><a class="reference internal" href="#hash-message-digest" id="id11">Hash (Message Digest)</a><ul>
<li><a class="reference internal" href="#id1" id="id12">Dependencies</a></li>
<li><a class="reference internal" href="#id2" id="id13">Function reference</a></li>
</ul>
</li>
<li><a class="reference internal" href="#multibyte-string" id="id14">Multibyte String</a><ul>
<li><a class="reference internal" href="#id3" id="id15">Dependencies</a></li>
<li><a class="reference internal" href="#id4" id="id16">Function reference</a></li>
</ul>
</li>
<li><a class="reference internal" href="#standard-functions" id="id17">Standard Functions</a><ul>
<li><a class="reference internal" href="#id5" id="id18">Dependencies</a></li>
<li><a class="reference internal" href="#id6" id="id19">Function reference</a></li>
</ul>
</li>
</ul>
</div>
<div class="custom-index container"></div><div class="section" id="password-hashing">
<h2><a class="toc-backref" href="#id7">Password Hashing</a><a class="headerlink" href="#password-hashing" title="Permalink to this headline">¶</a></h2>
<p>This set of compatibility functions offers a “backport” of PHP’s
standard <a class="reference external" href="http://php.net/password">Password Hashing extension</a>
that is otherwise available only since PHP 5.5.</p>
<div class="section" id="dependencies">
<h3><a class="toc-backref" href="#id8">Dependencies</a><a class="headerlink" href="#dependencies" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li>PHP 5.3.7</li>
<li><code class="docutils literal"><span class="pre">CRYPT_BLOWFISH</span></code> support for <code class="docutils literal"><span class="pre">crypt()</span></code></li>
</ul>
</div>
<div class="section" id="constants">
<h3><a class="toc-backref" href="#id9">Constants</a><a class="headerlink" href="#constants" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li><code class="docutils literal"><span class="pre">PASSWORD_BCRYPT</span></code></li>
<li><code class="docutils literal"><span class="pre">PASSWORD_DEFAULT</span></code></li>
</ul>
</div>
<div class="section" id="function-reference">
<h3><a class="toc-backref" href="#id10">Function reference</a><a class="headerlink" href="#function-reference" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="password_get_info">
<code class="descname">password_get_info</code><span class="sig-paren">(</span><em>$hash</em><span class="sig-paren">)</span><a class="headerlink" href="#password_get_info" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$hash</strong> (<em>string</em>) – Password hash</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Information about the hashed password</p>
</td>
</tr>
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">array</p>
</td>
</tr>
</tbody>
</table>
<p>For more information, please refer to the <a class="reference external" href="http://php.net/password_get_info">PHP manual for
password_get_info()</a>.</p>
</dd></dl>

<dl class="function">
<dt id="password_hash">
<code class="descname">password_hash</code><span class="sig-paren">(</span><em>$password</em>, <em>$algo</em><span class="optional">[</span>, <em>$options = array()</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#password_hash" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$password</strong> (<em>string</em>) – Plain-text password</li>
<li><strong>$algo</strong> (<em>int</em>) – Hashing algorithm</li>
<li><strong>$options</strong> (<em>array</em>) – Hashing options</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Hashed password or FALSE on failure</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>For more information, please refer to the <a class="reference external" href="http://php.net/password_hash">PHP manual for
password_hash()</a>.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Unless you provide your own (and valid) salt, this function
has a further dependency on an available CSPRNG source. Each
of the following would satisfy that:
- <code class="docutils literal"><span class="pre">mcrypt_create_iv()</span></code> with <code class="docutils literal"><span class="pre">MCRYPT_DEV_URANDOM</span></code>
- <code class="docutils literal"><span class="pre">openssl_random_pseudo_bytes()</span></code>
- /dev/arandom
- /dev/urandom</p>
</div>
</dd></dl>

<dl class="function">
<dt id="password_needs_rehash">
<code class="descname">password_needs_rehash</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#password_needs_rehash" 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>$hash</strong> (<em>string</em>) – Password hash</li>
<li><strong>$algo</strong> (<em>int</em>) – Hashing algorithm</li>
<li><strong>$options</strong> (<em>array</em>) – Hashing options</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 hash should be rehashed to match the given algorithm and options, FALSE otherwise</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>For more information, please refer to the <a class="reference external" href="http://php.net/password_needs_rehash">PHP manual for
password_needs_rehash()</a>.</p>
</dd></dl>

<dl class="function">
<dt id="password_verify">
<code class="descname">password_verify</code><span class="sig-paren">(</span><em>$password</em>, <em>$hash</em><span class="sig-paren">)</span><a class="headerlink" href="#password_verify" 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>$password</strong> (<em>string</em>) – Plain-text password</li>
<li><strong>$hash</strong> (<em>string</em>) – Password hash</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 password matches the hash, 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>For more information, please refer to the <a class="reference external" href="http://php.net/password_verify">PHP manual for
password_verify()</a>.</p>
</dd></dl>

</div>
</div>
<div class="section" id="hash-message-digest">
<h2><a class="toc-backref" href="#id11">Hash (Message Digest)</a><a class="headerlink" href="#hash-message-digest" title="Permalink to this headline">¶</a></h2>
<p>This compatibility layer contains backports for the <code class="docutils literal"><span class="pre">hash_equals()</span></code>
and <code class="docutils literal"><span class="pre">hash_pbkdf2()</span></code> functions, which otherwise require PHP 5.6 and/or
PHP 5.5 respectively.</p>
<div class="section" id="id1">
<h3><a class="toc-backref" href="#id12">Dependencies</a><a class="headerlink" href="#id1" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li>None</li>
</ul>
</div>
<div class="section" id="id2">
<h3><a class="toc-backref" href="#id13">Function reference</a><a class="headerlink" href="#id2" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="hash_equals">
<code class="descname">hash_equals</code><span class="sig-paren">(</span><em>$known_string</em>, <em>$user_string</em><span class="sig-paren">)</span><a class="headerlink" href="#hash_equals" 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>$known_string</strong> (<em>string</em>) – Known string</li>
<li><strong>$user_string</strong> (<em>string</em>) – User-supplied string</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 strings match, FALSE otherwise</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>For more information, please refer to the <a class="reference external" href="http://php.net/hash_equals">PHP manual for
hash_equals()</a>.</p>
</dd></dl>

<dl class="function">
<dt id="hash_pbkdf2">
<code class="descname">hash_pbkdf2</code><span class="sig-paren">(</span><em>$algo</em>, <em>$password</em>, <em>$salt</em>, <em>$iterations</em><span class="optional">[</span>, <em>$length = 0</em><span class="optional">[</span>, <em>$raw_output = FALSE</em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#hash_pbkdf2" 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>$algo</strong> (<em>string</em>) – Hashing algorithm</li>
<li><strong>$password</strong> (<em>string</em>) – Password</li>
<li><strong>$salt</strong> (<em>string</em>) – Hash salt</li>
<li><strong>$iterations</strong> (<em>int</em>) – Number of iterations to perform during derivation</li>
<li><strong>$length</strong> (<em>int</em>) – Output string length</li>
<li><strong>$raw_output</strong> (<em>bool</em>) – Whether to return raw binary data</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Password-derived key or FALSE on failure</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>For more information, please refer to the <a class="reference external" href="http://php.net/hash_pbkdf2">PHP manual for
hash_pbkdf2()</a>.</p>
</dd></dl>

</div>
</div>
<div class="section" id="multibyte-string">
<h2><a class="toc-backref" href="#id14">Multibyte String</a><a class="headerlink" href="#multibyte-string" title="Permalink to this headline">¶</a></h2>
<p>This set of compatibility functions offers limited support for PHP’s
<a class="reference external" href="http://php.net/mbstring">Multibyte String extension</a>. Because of
the limited alternative solutions, only a few functions are available.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">When a character set parameter is ommited,
<code class="docutils literal"><span class="pre">$config['charset']</span></code> will be used.</p>
</div>
<div class="section" id="id3">
<h3><a class="toc-backref" href="#id15">Dependencies</a><a class="headerlink" href="#id3" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li><a class="reference external" href="http://php.net/iconv">iconv</a> extension</li>
</ul>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">This dependency is optional and these functions will
always be declared. If iconv is not available, they WILL
fall-back to their non-mbstring versions.</p>
</div>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">Where a character set is supplied, it must be
supported by iconv and in a format that it recognizes.</p>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">For you own dependency check on the actual mbstring
extension, use the <code class="docutils literal"><span class="pre">MB_ENABLED</span></code> constant.</p>
</div>
</div>
<div class="section" id="id4">
<h3><a class="toc-backref" href="#id16">Function reference</a><a class="headerlink" href="#id4" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="mb_strlen">
<code class="descname">mb_strlen</code><span class="sig-paren">(</span><em>$str</em><span class="optional">[</span>, <em>$encoding = NULL</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#mb_strlen" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$str</strong> (<em>string</em>) – Input string</li>
<li><strong>$encoding</strong> (<em>string</em>) – Character set</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Number of characters in the input string or FALSE on failure</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>For more information, please refer to the <a class="reference external" href="http://php.net/mb_strlen">PHP manual for
mb_strlen()</a>.</p>
</dd></dl>

<dl class="function">
<dt id="mb_strpos">
<code class="descname">mb_strpos</code><span class="sig-paren">(</span><em>$haystack</em>, <em>$needle</em><span class="optional">[</span>, <em>$offset = 0</em><span class="optional">[</span>, <em>$encoding = NULL</em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#mb_strpos" 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>$haystack</strong> (<em>string</em>) – String to search in</li>
<li><strong>$needle</strong> (<em>string</em>) – Part of string to search for</li>
<li><strong>$offset</strong> (<em>int</em>) – Search offset</li>
<li><strong>$encoding</strong> (<em>string</em>) – Character set</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Numeric character position of where $needle was found or FALSE 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>For more information, please refer to the <a class="reference external" href="http://php.net/mb_strpos">PHP manual for
mb_strpos()</a>.</p>
</dd></dl>

<dl class="function">
<dt id="mb_substr">
<code class="descname">mb_substr</code><span class="sig-paren">(</span><em>$str</em>, <em>$start</em><span class="optional">[</span>, <em>$length = NULL</em><span class="optional">[</span>, <em>$encoding = NULL</em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#mb_substr" 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>$str</strong> (<em>string</em>) – Input string</li>
<li><strong>$start</strong> (<em>int</em>) – Position of first character</li>
<li><strong>$length</strong> (<em>int</em>) – Maximum number of characters</li>
<li><strong>$encoding</strong> (<em>string</em>) – Character set</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Portion of $str specified by $start and $length or FALSE on failure</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>For more information, please refer to the <a class="reference external" href="http://php.net/mb_substr">PHP manual for
mb_substr()</a>.</p>
</dd></dl>

</div>
</div>
<div class="section" id="standard-functions">
<h2><a class="toc-backref" href="#id17">Standard Functions</a><a class="headerlink" href="#standard-functions" title="Permalink to this headline">¶</a></h2>
<p>This set of compatibility functions offers support for a few
standard functions in PHP that otherwise require a newer PHP version.</p>
<div class="section" id="id5">
<h3><a class="toc-backref" href="#id18">Dependencies</a><a class="headerlink" href="#id5" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li>None</li>
</ul>
</div>
<div class="section" id="id6">
<h3><a class="toc-backref" href="#id19">Function reference</a><a class="headerlink" href="#id6" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="array_column">
<code class="descname">array_column</code><span class="sig-paren">(</span><em>array $array</em>, <em>$column_key</em><span class="optional">[</span>, <em>$index_key = NULL</em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#array_column" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$array</strong> (<em>array</em>) – Array to fetch results from</li>
<li><strong>$column_key</strong> (<em>mixed</em>) – Key of the column to return values from</li>
<li><strong>$index_key</strong> (<em>mixed</em>) – Key to use for the returned values</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">An array of values representing a single column from the input array</p>
</td>
</tr>
<tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><p class="first last">array</p>
</td>
</tr>
</tbody>
</table>
<p>For more information, please refer to the <a class="reference external" href="http://php.net/array_column">PHP manual for
array_column()</a>.</p>
</dd></dl>

<dl class="function">
<dt id="hex2bin">
<code class="descname">hex2bin</code><span class="sig-paren">(</span><em>$data</em><span class="sig-paren">)</span><a class="headerlink" href="#hex2bin" title="Permalink to this definition">¶</a></dt>
<dd><table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>$data</strong> (<em>array</em>) – Hexadecimal representation of data</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first">Binary representation of the given data</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>For more information, please refer to the <a class="reference external" href="http://php.net/hex2bin">PHP manual for hex2bin()</a>.</p>
</dd></dl>

</div>
</div>
</div>


          </div>
          <footer>
  
    <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
      
        <a href="routing.html" class="btn btn-neutral float-right" title="URI Routing">Next <span class="fa fa-arrow-circle-right"></span></a>
      
      
        <a href="common_functions.html" class="btn btn-neutral" title="Common Functions"><span class="fa fa-arrow-circle-left"></span> Previous</a>
      
    </div>
  

  <hr/>

  <div role="contentinfo">
    <p>
        &copy; Copyright 2014 - 2019, British Columbia Institute of Technology.
      Last updated on Sep 19, 2019.
    </p>
  </div>

  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>
  

    <script type="text/javascript">
        var DOCUMENTATION_OPTIONS = {
            URL_ROOT:'../',
            VERSION:'3.1.11',
            COLLAPSE_INDEX:false,
            FILE_SUFFIX:'.html',
            HAS_SOURCE:  false
        };
    </script>
      <script type="text/javascript" src="../_static/jquery.js"></script>
      <script type="text/javascript" src="../_static/underscore.js"></script>
      <script type="text/javascript" src="../_static/doctools.js"></script>

  
    <script type="text/javascript" src="../_static/js/theme.js"></script>
  

  <script type="text/javascript">
      jQuery(function () {
          SphinxRtdTheme.StickyNav.enable();
      });
  </script>
   

</body>
</html>