perlclib - Internal replacements for standard C library functions

<!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>perlclib - Internal replacements for standard C library functions - Perldoc Browser</title> <link rel="search" href="/opensearch.xml" type="application/opensearchdescription+xml" title="Perldoc Browser"> <link rel="canonical" href="https://perldoc.perl.org/perlclib"> <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">5.6.1</a> <div class="dropdown-menu" aria-labelledby="dropdownlink-stable"> <a class="dropdown-item" href="/perlclib">Latest</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.40.1/perlclib">5.40.1</a> <a class="dropdown-item" href="/5.40.0/perlclib">5.40.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.38.3/perlclib">5.38.3</a> <a class="dropdown-item" href="/5.38.2/perlclib">5.38.2</a> <a class="dropdown-item" href="/5.38.1/perlclib">5.38.1</a> <a class="dropdown-item" href="/5.38.0/perlclib">5.38.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.36.3/perlclib">5.36.3</a> <a class="dropdown-item" href="/5.36.2/perlclib">5.36.2</a> <a class="dropdown-item" href="/5.36.1/perlclib">5.36.1</a> <a class="dropdown-item" href="/5.36.0/perlclib">5.36.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.34.3/perlclib">5.34.3</a> <a class="dropdown-item" href="/5.34.2/perlclib">5.34.2</a> <a class="dropdown-item" href="/5.34.1/perlclib">5.34.1</a> <a class="dropdown-item" href="/5.34.0/perlclib">5.34.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.32.1/perlclib">5.32.1</a> <a class="dropdown-item" href="/5.32.0/perlclib">5.32.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.30.3/perlclib">5.30.3</a> <a class="dropdown-item" href="/5.30.2/perlclib">5.30.2</a> <a class="dropdown-item" href="/5.30.1/perlclib">5.30.1</a> <a class="dropdown-item" href="/5.30.0/perlclib">5.30.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.28.3/perlclib">5.28.3</a> <a class="dropdown-item" href="/5.28.2/perlclib">5.28.2</a> <a class="dropdown-item" href="/5.28.1/perlclib">5.28.1</a> <a class="dropdown-item" href="/5.28.0/perlclib">5.28.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.26.3/perlclib">5.26.3</a> <a class="dropdown-item" href="/5.26.2/perlclib">5.26.2</a> <a class="dropdown-item" href="/5.26.1/perlclib">5.26.1</a> <a class="dropdown-item" href="/5.26.0/perlclib">5.26.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.24.4/perlclib">5.24.4</a> <a class="dropdown-item" href="/5.24.3/perlclib">5.24.3</a> <a class="dropdown-item" href="/5.24.2/perlclib">5.24.2</a> <a class="dropdown-item" href="/5.24.1/perlclib">5.24.1</a> <a class="dropdown-item" href="/5.24.0/perlclib">5.24.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.22.4/perlclib">5.22.4</a> <a class="dropdown-item" href="/5.22.3/perlclib">5.22.3</a> <a class="dropdown-item" href="/5.22.2/perlclib">5.22.2</a> <a class="dropdown-item" href="/5.22.1/perlclib">5.22.1</a> <a class="dropdown-item" href="/5.22.0/perlclib">5.22.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.20.3/perlclib">5.20.3</a> <a class="dropdown-item" href="/5.20.2/perlclib">5.20.2</a> <a class="dropdown-item" href="/5.20.1/perlclib">5.20.1</a> <a class="dropdown-item" href="/5.20.0/perlclib">5.20.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.18.4/perlclib">5.18.4</a> <a class="dropdown-item" href="/5.18.3/perlclib">5.18.3</a> <a class="dropdown-item" href="/5.18.2/perlclib">5.18.2</a> <a class="dropdown-item" href="/5.18.1/perlclib">5.18.1</a> <a class="dropdown-item" href="/5.18.0/perlclib">5.18.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.16.3/perlclib">5.16.3</a> <a class="dropdown-item" href="/5.16.2/perlclib">5.16.2</a> <a class="dropdown-item" href="/5.16.1/perlclib">5.16.1</a> <a class="dropdown-item" href="/5.16.0/perlclib">5.16.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.14.4/perlclib">5.14.4</a> <a class="dropdown-item" href="/5.14.3/perlclib">5.14.3</a> <a class="dropdown-item" href="/5.14.2/perlclib">5.14.2</a> <a class="dropdown-item" href="/5.14.1/perlclib">5.14.1</a> <a class="dropdown-item" href="/5.14.0/perlclib">5.14.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.12.5/perlclib">5.12.5</a> <a class="dropdown-item" href="/5.12.4/perlclib">5.12.4</a> <a class="dropdown-item" href="/5.12.3/perlclib">5.12.3</a> <a class="dropdown-item" href="/5.12.2/perlclib">5.12.2</a> <a class="dropdown-item" href="/5.12.1/perlclib">5.12.1</a> <a class="dropdown-item" href="/5.12.0/perlclib">5.12.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.10.1/perlclib">5.10.1</a> <a class="dropdown-item" href="/5.10.0/perlclib">5.10.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.8.9/perlclib">5.8.9</a> <a class="dropdown-item" href="/5.8.8/perlclib">5.8.8</a> <a class="dropdown-item" href="/5.8.7/perlclib">5.8.7</a> <a class="dropdown-item" href="/5.8.6/perlclib">5.8.6</a> <a class="dropdown-item" href="/5.8.5/perlclib">5.8.5</a> <a class="dropdown-item" href="/5.8.4/perlclib">5.8.4</a> <a class="dropdown-item" href="/5.8.3/perlclib">5.8.3</a> <a class="dropdown-item" href="/5.8.2/perlclib">5.8.2</a> <a class="dropdown-item" href="/5.8.1/perlclib">5.8.1</a> <a class="dropdown-item" href="/5.8.0/perlclib">5.8.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.6.2/perlclib">5.6.2</a> <a class="dropdown-item active" href="/5.6.1/perlclib">5.6.1</a> <a class="dropdown-item" href="/5.6.0/perlclib">5.6.0</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.005_04/perlclib">5.005_04</a> <a class="dropdown-item" href="/5.005_03/perlclib">5.005_03</a> <a class="dropdown-item" href="/5.005_02/perlclib">5.005_02</a> <a class="dropdown-item" href="/5.005_01/perlclib">5.005_01</a> <a class="dropdown-item" href="/5.005/perlclib">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/perlclib">blead</a> <a class="dropdown-item" href="/5.41.10/perlclib">5.41.10</a> <a class="dropdown-item" href="/5.41.9/perlclib">5.41.9</a> <a class="dropdown-item" href="/5.41.8/perlclib">5.41.8</a> <a class="dropdown-item" href="/5.41.7/perlclib">5.41.7</a> <a class="dropdown-item" href="/5.41.6/perlclib">5.41.6</a> <a class="dropdown-item" href="/5.41.5/perlclib">5.41.5</a> <a class="dropdown-item" href="/5.41.4/perlclib">5.41.4</a> <a class="dropdown-item" href="/5.41.3/perlclib">5.41.3</a> <a class="dropdown-item" href="/5.41.2/perlclib">5.41.2</a> <a class="dropdown-item" href="/5.41.1/perlclib">5.41.1</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.40.1-RC1/perlclib">5.40.1-RC1</a> <a class="dropdown-item" href="/5.40.0-RC2/perlclib">5.40.0-RC2</a> <a class="dropdown-item" href="/5.40.0-RC1/perlclib">5.40.0-RC1</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.39.10/perlclib">5.39.10</a> <a class="dropdown-item" href="/5.39.9/perlclib">5.39.9</a> <a class="dropdown-item" href="/5.39.8/perlclib">5.39.8</a> <a class="dropdown-item" href="/5.39.7/perlclib">5.39.7</a> <a class="dropdown-item" href="/5.39.6/perlclib">5.39.6</a> <a class="dropdown-item" href="/5.39.5/perlclib">5.39.5</a> <a class="dropdown-item" href="/5.39.4/perlclib">5.39.4</a> <a class="dropdown-item" href="/5.39.3/perlclib">5.39.3</a> <a class="dropdown-item" href="/5.39.2/perlclib">5.39.2</a> <a class="dropdown-item" href="/5.39.1/perlclib">5.39.1</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.38.3-RC1/perlclib">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="/5.6.1/perl">Perl</a> <a class="dropdown-item" href="/5.6.1/perlintro">Intro</a> <a class="dropdown-item" href="/5.6.1/perl#Tutorials">Tutorials</a> <a class="dropdown-item" href="/5.6.1/perlfaq">FAQs</a> <a class="dropdown-item" href="/5.6.1/perl#Reference-Manual">Reference</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.6.1/perlop">Operators</a> <a class="dropdown-item" href="/5.6.1/functions">Functions</a> <a class="dropdown-item" href="/5.6.1/variables">Variables</a> <a class="dropdown-item" href="/5.6.1/modules">Modules</a> <a class="dropdown-item" href="/5.6.1/perlutil">Utilities</a> <div class="dropdown-divider"></div> <a class="dropdown-item" href="/5.6.1/perldelta">Release Notes</a> <a class="dropdown-item" href="/5.6.1/perlcommunity">Community</a> <a class="dropdown-item" href="/5.6.1/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="/5.6.1/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="/5.6.1/perlclib">perlclib</a> <div id="more"> (<a href="/5.6.1/perlclib.txt">source</a>, <a href="https://metacpan.org/pod/perlclib">CPAN</a>) </div> </div> <div class="leading-notice"> You are viewing the version of this documentation from Perl 5.6.1. <a href="/perlclib">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="#DESCRIPTION">DESCRIPTION</a> <ul> <li> <a class="text-decoration-none" href="#Conventions">Conventions</a> </li> <li> <a class="text-decoration-none" href="#File-Operations">File Operations</a> </li> <li> <a class="text-decoration-none" href="#File-Input-and-Output">File Input and Output</a> </li> <li> <a class="text-decoration-none" href="#File-Positioning">File Positioning</a> </li> <li> <a class="text-decoration-none" href="#Memory-Management-and-String-Handling">Memory Management and String Handling</a> </li> <li> <a class="text-decoration-none" href="#Character-Class-Tests">Character Class Tests</a> </li> <li> <a class="text-decoration-none" href="#stdlib.h-functions">stdlib.h functions</a> </li> <li> <a class="text-decoration-none" href="#Miscellaneous-functions">Miscellaneous functions</a> </li> </ul> </li> <li> <a class="text-decoration-none" href="#SEE-ALSO">SEE ALSO</a> </li> </ul> <h1 id="NAME"><a class="permalink" href="#NAME">#</a>NAME</h1> <p>perlclib - Internal replacements for standard C library functions</p> <h1 id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">#</a>DESCRIPTION</h1> <p>One thing Perl porters should note is that <i>perl</i> doesn't tend to use that much of the C standard library internally; you'll see very little use of, for example, the <i>ctype.h</i> functions in there. This is because Perl tends to reimplement or abstract standard library functions, so that we know exactly how they're going to operate.</p> <p>This is a reference card for people who are familiar with the C library and who want to do things the Perl way; to tell them which functions they ought to use instead of the more normal C functions.</p> <h2 id="Conventions"><a class="permalink" href="#Conventions">#</a>Conventions</h2> <p>In the following tables:</p> <dl> <dt id="t"><a class="permalink" href="#t">#</a><code>t</code></dt> <dd> <p>is a type.</p> </dd> <dt id="p"><a class="permalink" href="#p">#</a><code>p</code></dt> <dd> <p>is a pointer.</p> </dd> <dt id="n"><a class="permalink" href="#n">#</a><code>n</code></dt> <dd> <p>is a number.</p> </dd> <dt id="s"><a class="permalink" href="#s">#</a><code>s</code></dt> <dd> <p>is a string.</p> </dd> </dl> <p><code>sv</code>, <code>av</code>, <code>hv</code>, etc. represent variables of their respective types.</p> <h2 id="File-Operations"><a class="permalink" href="#File-Operations">#</a><a id="File"></a>File Operations</h2> <p>Instead of the <i>stdio.h</i> functions, you should use the Perl abstraction layer. Instead of <code>FILE*</code> types, you need to be handling <code>PerlIO*</code> types. Don't forget that with the new PerlIO layered I/O abstraction <code>FILE*</code> types may not even be available. See also the <code>perlapio</code> documentation for more information about the following functions:</p> <pre><code class="plaintext">Instead Of: Use: stdin PerlIO_stdin() stdout PerlIO_stdout() stderr PerlIO_stderr() fopen(fn, mode) PerlIO_open(fn, mode) freopen(fn, mode, stream) PerlIO_reopen(fn, mode, perlio) (Deprecated) fflush(stream) PerlIO_flush(perlio) fclose(stream) PerlIO_close(perlio)</code></pre> <h2 id="File-Input-and-Output"><a class="permalink" href="#File-Input-and-Output">#</a><a id="File1"></a>File Input and Output</h2> <pre><code class="plaintext">Instead Of: Use: fprintf(stream, fmt, ...) PerlIO_printf(perlio, fmt, ...) [f]getc(stream) PerlIO_getc(perlio) [f]putc(stream, n) PerlIO_putc(perlio, n) ungetc(n, stream) PerlIO_ungetc(perlio, n)</code></pre> <p>Note that the PerlIO equivalents of <code>fread</code> and <code>fwrite</code> are slightly different from their C library counterparts:</p> <pre><code class="plaintext">fread(p, size, n, stream) PerlIO_read(perlio, buf, numbytes) fwrite(p, size, n, stream) PerlIO_write(perlio, buf, numbytes) fputs(s, stream) PerlIO_puts(perlio, s)</code></pre> <p>There is no equivalent to <code>fgets</code>; one should use <code>sv_gets</code> instead:</p> <pre><code class="plaintext">fgets(s, n, stream) sv_gets(sv, perlio, append)</code></pre> <h2 id="File-Positioning"><a class="permalink" href="#File-Positioning">#</a><a id="File2"></a>File Positioning</h2> <pre><code class="plaintext">Instead Of: Use: feof(stream) PerlIO_eof(perlio) fseek(stream, n, whence) PerlIO_seek(perlio, n, whence) rewind(stream) PerlIO_rewind(perlio) fgetpos(stream, p) PerlIO_getpos(perlio, sv) fsetpos(stream, p) PerlIO_setpos(perlio, sv) ferror(stream) PerlIO_error(perlio) clearerr(stream) PerlIO_clearerr(perlio)</code></pre> <h2 id="Memory-Management-and-String-Handling"><a class="permalink" href="#Memory-Management-and-String-Handling">#</a><a id="Memory"></a>Memory Management and String Handling</h2> <pre><code class="plaintext">Instead Of: Use: t* p = malloc(n) New(id, p, n, t) t* p = calloc(n, s) Newz(id, p, n, t) p = realloc(p, n) Renew(p, n, t) memcpy(dst, src, n) Copy(src, dst, n, t) memmove(dst, src, n) Move(src, dst, n, t) memcpy/*(struct foo *) StructCopy(src, dst, t) free(p) Safefree(p) strdup(p) savepv(p) strndup(p, n) savepvn(p, n) (Hey, strndup doesn't exist!) strstr(big, little) instr(big, little) strcmp(s1, s2) strLE(s1, s2) / strEQ(s1, s2) / strGT(s1,s2) strncmp(s1, s2, n) strnNE(s1, s2, n) / strnEQ(s1, s2, n)</code></pre> <p>Notice the different order of arguments to <code>Copy</code> and <code>Move</code> than used in <code>memcpy</code> and <code>memmove</code>.</p> <p>Most of the time, though, you'll want to be dealing with SVs internally instead of raw <code>char *</code> strings:</p> <pre><code class="plaintext">strlen(s) sv_len(sv) strcpy(dt, src) sv_setpv(sv, s) strncpy(dt, src, n) sv_setpvn(sv, s, n) strcat(dt, src) sv_catpv(sv, s) strncat(dt, src) sv_catpvn(sv, s) sprintf(s, fmt, ...) sv_setpvf(sv, fmt, ...)</code></pre> <p>Note also the existence of <code>sv_catpvf</code> and <code>sv_catpvfn</code>, combining concatenation with formatting.</p> <h2 id="Character-Class-Tests"><a class="permalink" href="#Character-Class-Tests">#</a><a id="Character"></a>Character Class Tests</h2> <p>There are two types of character class tests that Perl implements: one type deals in <code>char</code>s and are thus <b>not</b> Unicode aware (and hence deprecated unless you <b>know</b> you should use them) and the other type deal in <code>UV</code>s and know about Unicode properties. In the following table, <code>c</code> is a <code>char</code>, and <code>u</code> is a Unicode codepoint.</p> <pre><code class="plaintext">Instead Of: Use: But better use: isalnum(c) isALNUM(c) isALNUM_uni(u) isalpha(c) isALPHA(c) isALPHA_uni(u) iscntrl(c) isCNTRL(c) isCNTRL_uni(u) isdigit(c) isDIGIT(c) isDIGIT_uni(u) isgraph(c) isGRAPH(c) isGRAPH_uni(u) islower(c) isLOWER(c) isLOWER_uni(u) isprint(c) isPRINT(c) isPRINT_uni(u) ispunct(c) isPUNCT(c) isPUNCT_uni(u) isspace(c) isSPACE(c) isSPACE_uni(u) isupper(c) isUPPER(c) isUPPER_uni(u) isxdigit(c) isXDIGIT(c) isXDIGIT_uni(u) tolower(c) toLOWER(c) toLOWER_uni(u) toupper(c) toUPPER(c) toUPPER_uni(u)</code></pre> <h2 id="stdlib.h-functions"><a class="permalink" href="#stdlib.h-functions">#</a><a id="stdlib"></a><i>stdlib.h</i> functions</h2> <pre><code class="plaintext">Instead Of: Use: atof(s) Atof(s) atol(s) Atol(s) strtod(s, *p) Nothing. Just don't use it. strtol(s, *p, n) Strtol(s, *p, n) strtoul(s, *p, n) Strtoul(s, *p, n)</code></pre> <p>Notice also the <code>scan_bin</code>, <code>scan_hex</code>, and <code>scan_oct</code> functions in <i>util.c</i> for converting strings representing numbers in the respective bases into <code>NV</code>s.</p> <p>In theory <code>Strtol</code> and <code>Strtoul</code> may not be defined if the machine perl is built on doesn't actually have strtol and strtoul. But as those 2 functions are part of the 1989 ANSI C spec we suspect you'll find them everywhere by now.</p> <pre><code>int rand() double Drand01() srand(n) { seedDrand01((Rand_seed_t)n); PL_srand_called = TRUE; } exit(n) my_exit(n) system(s) Don't. Look at pp_system or use my_popen getenv(s) PerlEnv_getenv(s) setenv(s, val) my_putenv(s, val)</code></pre> <h2 id="Miscellaneous-functions"><a class="permalink" href="#Miscellaneous-functions">#</a><a id="Miscellaneous"></a>Miscellaneous functions</h2> <p>You should not even <b>want</b> to use <i>setjmp.h</i> functions, but if you think you do, use the <code>JMPENV</code> stack in <i>scope.h</i> instead.</p> <p>For <code>signal</code>/<code>sigaction</code>, use <code>rsignal(signo, handler)</code>.</p> <h1 id="SEE-ALSO"><a class="permalink" href="#SEE-ALSO">#</a><a id="SEE"></a>SEE ALSO</h1> <p><code>perlapi</code>, <code>perlapio</code>, <code>perlguts</code></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

perlclib - Internal replacements for standard C library functions - Perldoc Browser