IO::Zlib - IO:: style interface to Compress::Zlib

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>IO::Zlib - IO:: style interface to Compress::Zlib - Perldoc Browser</title> <link rel="search" href="/opensearch.xml" type="application/opensearchdescription+xml" title="Perldoc Browser"> <link rel="canonical" href="https://perldoc.perl.org/IO::Zlib"> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" integrity="sha384-JcKb8q3iqJ61gNV9KGb8thSsNjpSL0n8PARn9HuZOnIxN0hoP+VmmDGMN5t9UJ0Z" crossorigin="anonymous"> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/10.5.0/styles/stackoverflow-light.min.css" integrity="sha512-cG1IdFxqipi3gqLmksLtuk13C+hBa57a6zpWxMeoY3Q9O6ooFxq50DayCdm0QrDgZjMUn23z/0PMZlgft7Yp5Q==" crossorigin="anonymous" /> <style> body { background: #f4f4f5; color: #020202; } .navbar-dark { background-image: -webkit-linear-gradient(top, #005f85 0, #002e49 100%); background-image: -o-linear-gradient(top, #005f85 0, #002e49 100%); background-image: linear-gradient(to bottom, #005f85 0, #002e49 100%); filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ff005f85', endColorstr='#ff002e49', GradientType=0); background-repeat: repeat-x; } .navbar-dark .navbar-nav .nav-link, .navbar-dark .navbar-nav .nav-link:focus { color: #fff } .navbar-dark .navbar-nav .nav-link:hover { color: #ffef68 } #wrapperlicious { margin: 0 auto; font: 0.9em 'Helvetica Neue', Helvetica, sans-serif; font-weight: normal; line-height: 1.5em; margin: 0; padding: 0; } #wrapperlicious h1 { font-size: 1.5em } #wrapperlicious h2 { font-size: 1.3em } #wrapperlicious h3 { font-size: 1.1em } #wrapperlicious h4 { font-size: 0.9em } #wrapperlicious h1, #wrapperlicious h2, #wrapperlicious h3, #wrapperlicious h4, #wrapperlicious dt { color: #020202; margin-top: 1em; margin-bottom: 1em; position: relative; font-weight: bold; } #wrapperlicious a { color: inherit; text-decoration: underline } #wrapperlicious #toc { text-decoration: none } #wrapperlicious a:hover { color: #2a2a2a } #wrapperlicious a img { border: 0 } #wrapperlicious :not(pre) > code { color: inherit; background-color: rgba(0, 0, 0, 0.04); border-radius: 3px; font: 0.9em Consolas, Menlo, Monaco, monospace; padding: 0.3em; } #wrapperlicious dd { margin: 0; margin-left: 2em; } #wrapperlicious dt { color: #2a2a2a; font-weight: bold; margin-left: 0.9em; } #wrapperlicious p { margin-bottom: 1em; margin-top: 1em; } #wrapperlicious li > p { margin-bottom: 0; margin-top: 0; } #wrapperlicious pre { border: 1px solid #c1c1c1; border-radius: 3px; font: 100% Consolas, Menlo, Monaco, monospace; margin-bottom: 1em; margin-top: 1em; } #wrapperlicious pre > code { display: block; background-color: #f6f6f6; font: 0.9em Consolas, Menlo, Monaco, monospace; line-height: 1.5em; text-align: left; white-space: pre; padding: 1em; } #wrapperlicious dl, #wrapperlicious ol, #wrapperlicious ul { margin-bottom: 1em; margin-top: 1em; } #wrapperlicious ul { list-style-type: square; } #wrapperlicious ul ul { margin-bottom: 0px; margin-top: 0px; } #footer { font-size: 0.8em; padding-top: 0.5em; text-align: center; } #more { display: inline; font-size: 0.8em; } #perldocdiv { background-color: #fff; border: 1px solid #c1c1c1; border-bottom-left-radius: 5px; border-bottom-right-radius: 5px; margin-left: auto; margin-right: auto; padding: 3em; padding-top: 1em; max-width: 960px; } #moduleversion { float: right } #wrapperlicious .leading-notice { font-style: italic; padding-left: 1em; margin-top: 1em; margin-bottom: 1em; } #wrapperlicious .permalink { display: none; left: -0.75em; position: absolute; padding-right: 0.25em; text-decoration: none; } #wrapperlicious h1:hover .permalink, #wrapperlicious h2:hover .permalink, #wrapperlicious h3:hover .permalink, #wrapperlicious h4:hover .permalink, #wrapperlicious dt:hover .permalink { display: block; } </style>  <script async src="https://www.googletagmanager.com/gtag/js?id=G-KVNWBNT5FB"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-KVNWBNT5FB'); gtag('config', 'UA-50555-3'); </script> </head> <body> <nav class="navbar navbar-expand-md navbar-dark bg-dark justify-content-between"> <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> <a class="navbar-brand" href="/"><img src="/images/perl_camel_30.png" width="30" height="30" class="d-inline-block align-top" alt="Perl Camel Logo"> Perldoc Browser</a> <div class="collapse navbar-collapse" id="navbarNav"> <ul class="navbar-nav mr-auto"> <li class="nav-item dropdown text-nowrap"> <a class="nav-link dropdown-toggle" href="#" id="dropdownlink-stable" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">5.28.3</a> <div class="dropdown-menu" aria-labelledby="dropdownlink-stable"> <a class="dropdown-item" href="/IO::Zlib">Latest</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.40.1/IO::Zlib">5.40.1</a> <a class="dropdown-item" href="/5.40.0/IO::Zlib">5.40.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.38.3/IO::Zlib">5.38.3</a> <a class="dropdown-item" href="/5.38.2/IO::Zlib">5.38.2</a> <a class="dropdown-item" href="/5.38.1/IO::Zlib">5.38.1</a> <a class="dropdown-item" href="/5.38.0/IO::Zlib">5.38.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.36.3/IO::Zlib">5.36.3</a> <a class="dropdown-item" href="/5.36.2/IO::Zlib">5.36.2</a> <a class="dropdown-item" href="/5.36.1/IO::Zlib">5.36.1</a> <a class="dropdown-item" href="/5.36.0/IO::Zlib">5.36.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.34.3/IO::Zlib">5.34.3</a> <a class="dropdown-item" href="/5.34.2/IO::Zlib">5.34.2</a> <a class="dropdown-item" href="/5.34.1/IO::Zlib">5.34.1</a> <a class="dropdown-item" href="/5.34.0/IO::Zlib">5.34.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.32.1/IO::Zlib">5.32.1</a> <a class="dropdown-item" href="/5.32.0/IO::Zlib">5.32.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.30.3/IO::Zlib">5.30.3</a> <a class="dropdown-item" href="/5.30.2/IO::Zlib">5.30.2</a> <a class="dropdown-item" href="/5.30.1/IO::Zlib">5.30.1</a> <a class="dropdown-item" href="/5.30.0/IO::Zlib">5.30.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item active" href="/5.28.3/IO::Zlib">5.28.3</a> <a class="dropdown-item" href="/5.28.2/IO::Zlib">5.28.2</a> <a class="dropdown-item" href="/5.28.1/IO::Zlib">5.28.1</a> <a class="dropdown-item" href="/5.28.0/IO::Zlib">5.28.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.26.3/IO::Zlib">5.26.3</a> <a class="dropdown-item" href="/5.26.2/IO::Zlib">5.26.2</a> <a class="dropdown-item" href="/5.26.1/IO::Zlib">5.26.1</a> <a class="dropdown-item" href="/5.26.0/IO::Zlib">5.26.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.24.4/IO::Zlib">5.24.4</a> <a class="dropdown-item" href="/5.24.3/IO::Zlib">5.24.3</a> <a class="dropdown-item" href="/5.24.2/IO::Zlib">5.24.2</a> <a class="dropdown-item" href="/5.24.1/IO::Zlib">5.24.1</a> <a class="dropdown-item" href="/5.24.0/IO::Zlib">5.24.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.22.4/IO::Zlib">5.22.4</a> <a class="dropdown-item" href="/5.22.3/IO::Zlib">5.22.3</a> <a class="dropdown-item" href="/5.22.2/IO::Zlib">5.22.2</a> <a class="dropdown-item" href="/5.22.1/IO::Zlib">5.22.1</a> <a class="dropdown-item" href="/5.22.0/IO::Zlib">5.22.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.20.3/IO::Zlib">5.20.3</a> <a class="dropdown-item" href="/5.20.2/IO::Zlib">5.20.2</a> <a class="dropdown-item" href="/5.20.1/IO::Zlib">5.20.1</a> <a class="dropdown-item" href="/5.20.0/IO::Zlib">5.20.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.18.4/IO::Zlib">5.18.4</a> <a class="dropdown-item" href="/5.18.3/IO::Zlib">5.18.3</a> <a class="dropdown-item" href="/5.18.2/IO::Zlib">5.18.2</a> <a class="dropdown-item" href="/5.18.1/IO::Zlib">5.18.1</a> <a class="dropdown-item" href="/5.18.0/IO::Zlib">5.18.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.16.3/IO::Zlib">5.16.3</a> <a class="dropdown-item" href="/5.16.2/IO::Zlib">5.16.2</a> <a class="dropdown-item" href="/5.16.1/IO::Zlib">5.16.1</a> <a class="dropdown-item" href="/5.16.0/IO::Zlib">5.16.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.14.4/IO::Zlib">5.14.4</a> <a class="dropdown-item" href="/5.14.3/IO::Zlib">5.14.3</a> <a class="dropdown-item" href="/5.14.2/IO::Zlib">5.14.2</a> <a class="dropdown-item" href="/5.14.1/IO::Zlib">5.14.1</a> <a class="dropdown-item" href="/5.14.0/IO::Zlib">5.14.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.12.5/IO::Zlib">5.12.5</a> <a class="dropdown-item" href="/5.12.4/IO::Zlib">5.12.4</a> <a class="dropdown-item" href="/5.12.3/IO::Zlib">5.12.3</a> <a class="dropdown-item" href="/5.12.2/IO::Zlib">5.12.2</a> <a class="dropdown-item" href="/5.12.1/IO::Zlib">5.12.1</a> <a class="dropdown-item" href="/5.12.0/IO::Zlib">5.12.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.10.1/IO::Zlib">5.10.1</a> <a class="dropdown-item" href="/5.10.0/IO::Zlib">5.10.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.8.9/IO::Zlib">5.8.9</a> <a class="dropdown-item" href="/5.8.8/IO::Zlib">5.8.8</a> <a class="dropdown-item" href="/5.8.7/IO::Zlib">5.8.7</a> <a class="dropdown-item" href="/5.8.6/IO::Zlib">5.8.6</a> <a class="dropdown-item" href="/5.8.5/IO::Zlib">5.8.5</a> <a class="dropdown-item" href="/5.8.4/IO::Zlib">5.8.4</a> <a class="dropdown-item" href="/5.8.3/IO::Zlib">5.8.3</a> <a class="dropdown-item" href="/5.8.2/IO::Zlib">5.8.2</a> <a class="dropdown-item" href="/5.8.1/IO::Zlib">5.8.1</a> <a class="dropdown-item" href="/5.8.0/IO::Zlib">5.8.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.6.2/IO::Zlib">5.6.2</a> <a class="dropdown-item" href="/5.6.1/IO::Zlib">5.6.1</a> <a class="dropdown-item" href="/5.6.0/IO::Zlib">5.6.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.005_04/IO::Zlib">5.005_04</a> <a class="dropdown-item" href="/5.005_03/IO::Zlib">5.005_03</a> <a class="dropdown-item" href="/5.005_02/IO::Zlib">5.005_02</a> <a class="dropdown-item" href="/5.005_01/IO::Zlib">5.005_01</a> <a class="dropdown-item" href="/5.005/IO::Zlib">5.005</a> </div> </li> <li class="nav-item dropdown text-nowrap"> <a class="nav-link dropdown-toggle" href="#" id="dropdownlink-dev" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Dev</a> <div class="dropdown-menu" aria-labelledby="dropdownlink-dev"> <a class="dropdown-item" href="/blead/IO::Zlib">blead</a> <a class="dropdown-item" href="/5.41.9/IO::Zlib">5.41.9</a> <a class="dropdown-item" href="/5.41.8/IO::Zlib">5.41.8</a> <a class="dropdown-item" href="/5.41.7/IO::Zlib">5.41.7</a> <a class="dropdown-item" href="/5.41.6/IO::Zlib">5.41.6</a> <a class="dropdown-item" href="/5.41.5/IO::Zlib">5.41.5</a> <a class="dropdown-item" href="/5.41.4/IO::Zlib">5.41.4</a> <a class="dropdown-item" href="/5.41.3/IO::Zlib">5.41.3</a> <a class="dropdown-item" href="/5.41.2/IO::Zlib">5.41.2</a> <a class="dropdown-item" href="/5.41.1/IO::Zlib">5.41.1</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.40.1-RC1/IO::Zlib">5.40.1-RC1</a> <a class="dropdown-item" href="/5.40.0-RC2/IO::Zlib">5.40.0-RC2</a> <a class="dropdown-item" href="/5.40.0-RC1/IO::Zlib">5.40.0-RC1</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.39.10/IO::Zlib">5.39.10</a> <a class="dropdown-item" href="/5.39.9/IO::Zlib">5.39.9</a> <a class="dropdown-item" href="/5.39.8/IO::Zlib">5.39.8</a> <a class="dropdown-item" href="/5.39.7/IO::Zlib">5.39.7</a> <a class="dropdown-item" href="/5.39.6/IO::Zlib">5.39.6</a> <a class="dropdown-item" href="/5.39.5/IO::Zlib">5.39.5</a> <a class="dropdown-item" href="/5.39.4/IO::Zlib">5.39.4</a> <a class="dropdown-item" href="/5.39.3/IO::Zlib">5.39.3</a> <a class="dropdown-item" href="/5.39.2/IO::Zlib">5.39.2</a> <a class="dropdown-item" href="/5.39.1/IO::Zlib">5.39.1</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.38.3-RC1/IO::Zlib">5.38.3-RC1</a> </div> </li> <li class="nav-item dropdown text-nowrap"> <a class="nav-link dropdown-toggle" href="#" id="dropdownlink-nav" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Documentation</a> <div class="dropdown-menu" aria-labelledby="dropdownlink-nav"> <a class="dropdown-item" href="/5.28.3/perl">Perl</a> <a class="dropdown-item" href="/5.28.3/perlintro">Intro</a> <a class="dropdown-item" href="/5.28.3/perl#Tutorials">Tutorials</a> <a class="dropdown-item" href="/5.28.3/perlfaq">FAQs</a> <a class="dropdown-item" href="/5.28.3/perl#Reference-Manual">Reference</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.28.3/perlop">Operators</a> <a class="dropdown-item" href="/5.28.3/functions">Functions</a> <a class="dropdown-item" href="/5.28.3/variables">Variables</a> <a class="dropdown-item" href="/5.28.3/modules">Modules</a> <a class="dropdown-item" href="/5.28.3/perlutil">Utilities</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.28.3/perldelta">Release Notes</a> <a class="dropdown-item" href="/5.28.3/perlcommunity">Community</a> <a class="dropdown-item" href="/5.28.3/perlhist">History</a> </div> </li> </ul> <ul class="navbar-nav"> <script> function set_expand (expand) { var perldocdiv = document.getElementById('perldocdiv'); var width = window.getComputedStyle(perldocdiv).getPropertyValue('max-width'); var expanded = (width == '' || width == 'none') ? true : false; if (expand === null) { expand = !expanded; } if ((expand && !expanded) || (!expand && expanded)) { perldocdiv.style.setProperty('max-width', expand ? 'none' : '960px'); var button_classlist = document.getElementById('content-expand-button').classList; if (expand) { button_classlist.add('btn-light'); button_classlist.remove('btn-outline-light'); } else { button_classlist.add('btn-outline-light'); button_classlist.remove('btn-light'); } } return expand; } function toggle_expand () { var expand = set_expand(null); document.cookie = 'perldoc_expand=' + (expand ? 1 : 0) + '; path=/; expires=Tue, 19 Jan 2038 03:14:07 UTC'; } function read_expand () { return document.cookie.split(';').some(function (item) { return item.indexOf('perldoc_expand=1') >= 0 }); } if (document.readyState === 'loading') { document.addEventListener('DOMContentLoaded', function () { if (read_expand()) { set_expand(true); } }); } else if (read_expand()) { set_expand(true); } </script> <button id="content-expand-button" type="button" class="btn btn-outline-light d-none d-lg-inline-block mr-4" onclick="toggle_expand()">Expand</button> </ul> <form class="form-inline" method="get" action="/5.28.3/search"> <input class="form-control mr-3" type="search" name="q" placeholder="Search" aria-label="Search" value=""> </form> </div> </nav> <div id="wrapperlicious" class="container-fluid"> <div id="perldocdiv"> <div id="links"> <a href="/5.28.3/IO::Zlib">IO::Zlib</a> <div id="more"> (<a href="/5.28.3/IO::Zlib.txt">source</a>, <a href="https://metacpan.org/pod/IO::Zlib">CPAN</a>) </div> <div id="moduleversion">version 1.10</div> </div> <div class="leading-notice"> You are viewing the version of this documentation from Perl 5.28.3. <a href="/IO::Zlib">View the latest version</a> </div> <h1><a id="toc">CONTENTS</a></h1> <ul> <li> <a class="text-decoration-none" href="#NAME">NAME</a> </li> <li> <a class="text-decoration-none" href="#SYNOPSIS">SYNOPSIS</a> </li> <li> <a class="text-decoration-none" href="#DESCRIPTION">DESCRIPTION</a> </li> <li> <a class="text-decoration-none" href="#CONSTRUCTOR">CONSTRUCTOR</a> </li> <li> <a class="text-decoration-none" href="#OBJECT-METHODS">OBJECT METHODS</a> </li> <li> <a class="text-decoration-none" href="#USING-THE-EXTERNAL-GZIP">USING THE EXTERNAL GZIP</a> </li> <li> <a class="text-decoration-none" href="#CLASS-METHODS">CLASS METHODS</a> </li> <li> <a class="text-decoration-none" href="#DIAGNOSTICS">DIAGNOSTICS</a> </li> <li> <a class="text-decoration-none" href="#SEE-ALSO">SEE ALSO</a> </li> <li> <a class="text-decoration-none" href="#HISTORY">HISTORY</a> </li> <li> <a class="text-decoration-none" href="#COPYRIGHT">COPYRIGHT</a> </li> </ul> <h1 id="NAME"><a class="permalink" href="#NAME">#</a>NAME</h1> <p>IO::Zlib - IO:: style interface to <a href="/5.28.3/Compress::Zlib">Compress::Zlib</a></p> <h1 id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">#</a>SYNOPSIS</h1> <p>With any version of Perl 5 you can use the basic OO interface:</p> <pre><code>use IO::Zlib; $fh = new IO::Zlib; if ($fh->open("file.gz", "rb")) { print <$fh>; $fh->close; } $fh = IO::Zlib->new("file.gz", "wb9"); if (defined $fh) { print $fh "bar\n"; $fh->close; } $fh = IO::Zlib->new("file.gz", "rb"); if (defined $fh) { print <$fh>; undef $fh; # automatically closes the file }</code></pre> <p>With Perl 5.004 you can also use the TIEHANDLE interface to access compressed files just like ordinary files:</p> <pre><code>use IO::Zlib; tie *FILE, 'IO::Zlib', "file.gz", "wb"; print FILE "line 1\nline2\n"; tie *FILE, 'IO::Zlib', "file.gz", "rb"; while (<FILE>) { print "LINE: ", $_ };</code></pre> <h1 id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">#</a>DESCRIPTION</h1> <p><code>IO::Zlib</code> provides an IO:: style interface to <a href="/5.28.3/Compress::Zlib">Compress::Zlib</a> and hence to gzip/zlib compressed files. It provides many of the same methods as the <a href="/5.28.3/IO::Handle">IO::Handle</a> interface.</p> <p>Starting from IO::Zlib version 1.02, IO::Zlib can also use an external <i>gzip</i> command. The default behaviour is to try to use an external <i>gzip</i> if no <code>Compress::Zlib</code> can be loaded, unless explicitly disabled by</p> <pre><code>use IO::Zlib qw(:gzip_external 0);</code></pre> <p>If explicitly enabled by</p> <pre><code>use IO::Zlib qw(:gzip_external 1);</code></pre> <p>then the external <i>gzip</i> is used <b>instead</b> of <code>Compress::Zlib</code>.</p> <h1 id="CONSTRUCTOR"><a class="permalink" href="#CONSTRUCTOR">#</a>CONSTRUCTOR</h1> <dl> <dt id="new-(-[ARGS]-)"><a class="permalink" href="#new-(-%5BARGS%5D-)">#</a><a id="new"></a><a id="new-ARGS"></a>new ( [ARGS] )</dt> <dd> <p>Creates an <code>IO::Zlib</code> object. If it receives any parameters, they are passed to the method <code>open</code>; if the open fails, the object is destroyed. Otherwise, it is returned to the caller.</p> </dd> </dl> <h1 id="OBJECT-METHODS"><a class="permalink" href="#OBJECT-METHODS">#</a><a id="OBJECT"></a>OBJECT METHODS</h1> <dl> <dt id="open-(-FILENAME,-MODE-)"><a class="permalink" href="#open-(-FILENAME,-MODE-)">#</a><a id="open"></a><a id="open-FILENAME-MODE"></a>open ( FILENAME, MODE )</dt> <dd> <p><code>open</code> takes two arguments. The first is the name of the file to open and the second is the open mode. The mode can be anything acceptable to <a href="/5.28.3/Compress::Zlib">Compress::Zlib</a> and by extension anything acceptable to <i>zlib</i> (that basically means POSIX fopen() style mode strings plus an optional number to indicate the compression level).</p> </dd> <dt id="opened"><a class="permalink" href="#opened">#</a>opened</dt> <dd> <p>Returns true if the object currently refers to a opened file.</p> </dd> <dt id="close"><a class="permalink" href="#close">#</a>close</dt> <dd> <p>Close the file associated with the object and disassociate the file from the handle. Done automatically on destroy.</p> </dd> <dt id="getc"><a class="permalink" href="#getc">#</a>getc</dt> <dd> <p>Return the next character from the file, or undef if none remain.</p> </dd> <dt id="getline"><a class="permalink" href="#getline">#</a>getline</dt> <dd> <p>Return the next line from the file, or undef on end of string. Can safely be called in an array context. Currently ignores $/ ($INPUT_RECORD_SEPARATOR or $RS when <a href="/5.28.3/English">English</a> is in use) and treats lines as delimited by "\n".</p> </dd> <dt id="getlines"><a class="permalink" href="#getlines">#</a>getlines</dt> <dd> <p>Get all remaining lines from the file. It will croak() if accidentally called in a scalar context.</p> </dd> <dt id="print-(-ARGS...-)"><a class="permalink" href="#print-(-ARGS...-)">#</a><a id="print"></a><a id="print-ARGS"></a>print ( ARGS... )</dt> <dd> <p>Print ARGS to the file.</p> </dd> <dt id="read-(-BUF,-NBYTES,-[OFFSET]-)"><a class="permalink" href="#read-(-BUF,-NBYTES,-%5BOFFSET%5D-)">#</a><a id="read"></a><a id="read-BUF-NBYTES-OFFSET"></a>read ( BUF, NBYTES, [OFFSET] )</dt> <dd> <p>Read some bytes from the file. Returns the number of bytes actually read, 0 on end-of-file, undef on error.</p> </dd> <dt id="eof"><a class="permalink" href="#eof">#</a>eof</dt> <dd> <p>Returns true if the handle is currently positioned at end of file?</p> </dd> <dt id="seek-(-OFFSET,-WHENCE-)"><a class="permalink" href="#seek-(-OFFSET,-WHENCE-)">#</a><a id="seek"></a><a id="seek-OFFSET-WHENCE"></a>seek ( OFFSET, WHENCE )</dt> <dd> <p>Seek to a given position in the stream. Not yet supported.</p> </dd> <dt id="tell"><a class="permalink" href="#tell">#</a>tell</dt> <dd> <p>Return the current position in the stream, as a numeric offset. Not yet supported.</p> </dd> <dt id="setpos-(-POS-)"><a class="permalink" href="#setpos-(-POS-)">#</a><a id="setpos"></a><a id="setpos-POS"></a>setpos ( POS )</dt> <dd> <p>Set the current position, using the opaque value returned by <code>getpos()</code>. Not yet supported.</p> </dd> <dt id="getpos-(-POS-)"><a class="permalink" href="#getpos-(-POS-)">#</a><a id="getpos"></a><a id="getpos-POS"></a>getpos ( POS )</dt> <dd> <p>Return the current position in the string, as an opaque object. Not yet supported.</p> </dd> </dl> <h1 id="USING-THE-EXTERNAL-GZIP"><a class="permalink" href="#USING-THE-EXTERNAL-GZIP">#</a><a id="USING"></a>USING THE EXTERNAL GZIP</h1> <p>If the external <i>gzip</i> is used, the following <code>open</code>s are used:</p> <pre><code>open(FH, "gzip -dc $filename |") # for read opens open(FH, " | gzip > $filename") # for write opens</code></pre> <p>You can modify the 'commands' for example to hardwire an absolute path by e.g.</p> <pre><code>use IO::Zlib ':gzip_read_open' => '/some/where/gunzip -c %s |'; use IO::Zlib ':gzip_write_open' => '| /some/where/gzip.exe > %s';</code></pre> <p>The <code>%s</code> is expanded to be the filename (<code>sprintf</code> is used, so be careful to escape any other <code>%</code> signs). The 'commands' are checked for sanity - they must contain the <code>%s</code>, and the read open must end with the pipe sign, and the write open must begin with the pipe sign.</p> <h1 id="CLASS-METHODS"><a class="permalink" href="#CLASS-METHODS">#</a><a id="CLASS"></a>CLASS METHODS</h1> <dl> <dt id="has_Compress_Zlib"><a class="permalink" href="#has_Compress_Zlib">#</a>has_Compress_Zlib</dt> <dd> <p>Returns true if <code>Compress::Zlib</code> is available. Note that this does not mean that <code>Compress::Zlib</code> is being used: see <a href="#gzip_external">"gzip_external"</a> and <a href="/5.28.3/gzip_used">gzip_used</a>.</p> </dd> <dt id="gzip_external"><a class="permalink" href="#gzip_external">#</a>gzip_external</dt> <dd> <p>Undef if an external <i>gzip</i> <b>can</b> be used if <code>Compress::Zlib</code> is not available (see <a href="#has_Compress_Zlib">"has_Compress_Zlib"</a>), true if an external <i>gzip</i> is explicitly used, false if an external <i>gzip</i> must not be used. See <a href="#gzip_used">"gzip_used"</a>.</p> </dd> <dt id="gzip_used"><a class="permalink" href="#gzip_used">#</a>gzip_used</dt> <dd> <p>True if an external <i>gzip</i> is being used, false if not.</p> </dd> <dt id="gzip_read_open"><a class="permalink" href="#gzip_read_open">#</a>gzip_read_open</dt> <dd> <p>Return the 'command' being used for opening a file for reading using an external <i>gzip</i>.</p> </dd> <dt id="gzip_write_open"><a class="permalink" href="#gzip_write_open">#</a>gzip_write_open</dt> <dd> <p>Return the 'command' being used for opening a file for writing using an external <i>gzip</i>.</p> </dd> </dl> <h1 id="DIAGNOSTICS"><a class="permalink" href="#DIAGNOSTICS">#</a>DIAGNOSTICS</h1> <dl> <dt id="IO::Zlib::getlines:-must-be-called-in-list-context"><a class="permalink" href="#IO::Zlib::getlines:-must-be-called-in-list-context">#</a><a id="IO"></a>IO::Zlib::getlines: must be called in list context</dt> <dd> <p>If you want read lines, you must read in list context.</p> </dd> <dt id="IO::Zlib::gzopen_external:-mode-'...'-is-illegal"><a class="permalink" href="#IO::Zlib::gzopen_external:-mode-'...'-is-illegal">#</a><a id="IO1"></a><a id="IO::Zlib::gzopen_external:-mode-...-is-illegal"></a>IO::Zlib::gzopen_external: mode '...' is illegal</dt> <dd> <p>Use only modes 'rb' or 'wb' or /wb[1-9]/.</p> </dd> <dt id="IO::Zlib::import:-'...'-is-illegal"><a class="permalink" href="#IO::Zlib::import:-'...'-is-illegal">#</a><a id="IO2"></a><a id="IO::Zlib::import:-...-is-illegal"></a>IO::Zlib::import: '...' is illegal</dt> <dd> <p>The known import symbols are the <code>:gzip_external</code>, <code>:gzip_read_open</code>, and <code>:gzip_write_open</code>. Anything else is not recognized.</p> </dd> <dt id="IO::Zlib::import:-':gzip_external'-requires-an-argument"><a class="permalink" href="#IO::Zlib::import:-':gzip_external'-requires-an-argument">#</a><a id="IO3"></a><a id="IO::Zlib::import:-:gzip_external-requires-an-argument"></a>IO::Zlib::import: ':gzip_external' requires an argument</dt> <dd> <p>The <code>:gzip_external</code> requires one boolean argument.</p> </dd> <dt id="IO::Zlib::import:-'gzip_read_open'-requires-an-argument"><a class="permalink" href="#IO::Zlib::import:-'gzip_read_open'-requires-an-argument">#</a><a id="IO4"></a><a id="IO::Zlib::import:-gzip_read_open-requires-an-argument"></a>IO::Zlib::import: 'gzip_read_open' requires an argument</dt> <dd> <p>The <code>:gzip_external</code> requires one string argument.</p> </dd> <dt id="IO::Zlib::import:-'gzip_read'-'...'-is-illegal"><a class="permalink" href="#IO::Zlib::import:-'gzip_read'-'...'-is-illegal">#</a><a id="IO5"></a><a id="IO::Zlib::import:-gzip_read-...-is-illegal"></a>IO::Zlib::import: 'gzip_read' '...' is illegal</dt> <dd> <p>The <code>:gzip_read_open</code> argument must end with the pipe sign (|) and have the <code>%s</code> for the filename. See <a href="#USING-THE-EXTERNAL-GZIP">"USING THE EXTERNAL GZIP"</a>.</p> </dd> <dt id="IO::Zlib::import:-'gzip_write_open'-requires-an-argument"><a class="permalink" href="#IO::Zlib::import:-'gzip_write_open'-requires-an-argument">#</a><a id="IO6"></a><a id="IO::Zlib::import:-gzip_write_open-requires-an-argument"></a>IO::Zlib::import: 'gzip_write_open' requires an argument</dt> <dd> <p>The <code>:gzip_external</code> requires one string argument.</p> </dd> <dt id="IO::Zlib::import:-'gzip_write_open'-'...'-is-illegal"><a class="permalink" href="#IO::Zlib::import:-'gzip_write_open'-'...'-is-illegal">#</a><a id="IO7"></a><a id="IO::Zlib::import:-gzip_write_open-...-is-illegal"></a>IO::Zlib::import: 'gzip_write_open' '...' is illegal</dt> <dd> <p>The <code>:gzip_write_open</code> argument must begin with the pipe sign (|) and have the <code>%s</code> for the filename. An output redirect (>) is also often a good idea, depending on your operating system shell syntax. See <a href="#USING-THE-EXTERNAL-GZIP">"USING THE EXTERNAL GZIP"</a>.</p> </dd> <dt id="IO::Zlib::import:-no-Compress::Zlib-and-no-external-gzip"><a class="permalink" href="#IO::Zlib::import:-no-Compress::Zlib-and-no-external-gzip">#</a><a id="IO8"></a>IO::Zlib::import: no Compress::Zlib and no external gzip</dt> <dd> <p>Given that we failed to load <code>Compress::Zlib</code> and that the use of an external <i>gzip</i> was disabled, IO::Zlib has not much chance of working.</p> </dd> <dt id="IO::Zlib::open:-needs-a-filename"><a class="permalink" href="#IO::Zlib::open:-needs-a-filename">#</a><a id="IO9"></a>IO::Zlib::open: needs a filename</dt> <dd> <p>No filename, no open.</p> </dd> <dt id="IO::Zlib::READ:-NBYTES-must-be-specified"><a class="permalink" href="#IO::Zlib::READ:-NBYTES-must-be-specified">#</a><a id="IO10"></a>IO::Zlib::READ: NBYTES must be specified</dt> <dd> <p>We must know how much to read.</p> </dd> <dt id="IO::Zlib::WRITE:-too-long-LENGTH"><a class="permalink" href="#IO::Zlib::WRITE:-too-long-LENGTH">#</a><a id="IO11"></a>IO::Zlib::WRITE: too long LENGTH</dt> <dd> <p>The LENGTH must be less than or equal to the buffer size.</p> </dd> </dl> <h1 id="SEE-ALSO"><a class="permalink" href="#SEE-ALSO">#</a><a id="SEE"></a>SEE ALSO</h1> <p><a href="/5.28.3/perlfunc">perlfunc</a>, <a href="/5.28.3/perlop#I%2FO-Operators">"I/O Operators" in perlop</a>, <a href="/5.28.3/IO::Handle">IO::Handle</a>, <a href="/5.28.3/Compress::Zlib">Compress::Zlib</a></p> <h1 id="HISTORY"><a class="permalink" href="#HISTORY">#</a>HISTORY</h1> <p>Created by Tom Hughes <<i>tom@compton.nu</i>>.</p> <p>Support for external gzip added by Jarkko Hietaniemi <<i>jhi@iki.fi</i>>.</p> <h1 id="COPYRIGHT"><a class="permalink" href="#COPYRIGHT">#</a>COPYRIGHT</h1> <p>Copyright (c) 1998-2004 Tom Hughes <<i>tom@compton.nu</i>>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.</p> </div> <div id="footer"> <p>Perldoc Browser is maintained by Dan Book (<a href="https://metacpan.org/author/DBOOK">DBOOK</a>). Please contact him via the <a href="https://github.com/Grinnz/perldoc-browser/issues">GitHub issue tracker</a> or <a href="mailto:dbook@cpan.org">email</a> regarding any issues with the site itself, search, or rendering of documentation.</p> <p>The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. Please contact them via the <a href="https://github.com/Perl/perl5/issues">Perl issue tracker</a>, the <a href="https://lists.perl.org/list/perl5-porters.html">mailing list</a>, or <a href="https://kiwiirc.com/client/irc.perl.org/p5p">IRC</a> to report any issues with the contents or format of the documentation.</p> </div> </div> <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.slim.min.js" integrity="sha512-/DXTXr6nQodMUiq+IUJYCt2PPOUjrHJ9wFrqpJ3XkgPNOZVfMok7cRw6CSxyCQxXn6ozlESsSh1/sMCTF1rL/g==" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.1/umd/popper.min.js" integrity="sha512-ubuT8Z88WxezgSqf3RLuNi5lmjstiJcyezx34yIU2gAHonIi27Na7atqzUZCOoY4CExaoFumzOsFQ2Ch+I/HCw==" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js" integrity="sha384-B4gt1jrGC7Jh4AgTPSdUtOBvfO8shuf57BaghqFfPlYxofvL8/KUEfYiJOMMV+rV" crossorigin="anonymous"></script> <script src="/js/highlight.pack.js"></script> <script>hljs.highlightAll();</script> </body> </html>

CINXE.COM

IO::Zlib - IO:: style interface to Compress::Zlib - Perldoc Browser