<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>Online Demo - Cppcheck</title> <link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Orbitron&text=Cppcheck" /> <link rel="stylesheet" type="text/css" href="/site/css/pack.css" /> <link rel="shortcut icon" type="image/x-icon" href="/favicon.ico" /> <script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> //<![CDATA[ window.jQuery || document.write('<script type="text/javascript" src="/site/js/jquery-1.10.2.min.js"><\/script>') //]]> </script> <script src="/site/js/pack.js" type="text/javascript"></script> <script type="text/javascript"> function checkCodeLength() { if (document.f.code.value.length > 1024) { alert("code length exceeded"); return false; } return true; } </script> </head> <body> <div id="header"> <div class="wrap"> <h1><a href="/">Cppcheck</a></h1> <p>A tool for static C/C++ code analysis</p> </div> <!-- .wrap --> </div> <!-- #header --> <div id="tabs"> <div class="wrap"> <ul> <li><a href="/">Home</a></li> <li><a href="http://sourceforge.net/apps/mediawiki/cppcheck/">Wiki</a></li> <li><a href="http://sourceforge.net/apps/phpbb/cppcheck/">Forum</a></li> <li><a href="http://sourceforge.net/apps/trac/cppcheck/">Issues</a></li> <li><a href="/devinfo/" title="Developer Information">Developer Info</a></li> <li><strong><a href="/demo/">Online Demo</a></strong></li> <li><a href="http://sourceforge.net/projects/cppcheck/">Project page</a></li> </ul> </div> <!-- .wrap --> </div> <!-- #tabs --> <div id="content"> <div class="wrap"> <h2>Online Demo</h2> <form action="/demo/report/" name="f" onsubmit="return checkCodeLength();" method="post" target="_blank"> <p><label for="code">Enter code:</label> <span class="maxChars">(max 1024 characters)</span><br /> <textarea id="code" name="code" rows="20" cols="80"> void f() { char *p; *p = 0; } </textarea><br /> <input type="submit" value="Check" /> <label><input type="checkbox" name="xml" value="1" />XML output</label></p> </form> <h3>Examples</h3> <p>This code can be copied and pasted in the edit box above.</p> <h4>NULL pointers</h4> <pre class="cpp geshicode"><span class="kw4">void</span> f1<span class="br0">(</span><span class="kw4">struct</span> fred_t <span class="sy2">*</span>p<span class="br0">)</span> <span class="br0">{</span> <span class="co1">// dereference p and then check if it's NULL</span> <span class="kw4">int</span> x <span class="sy1">=</span> p<span class="sy2">-</span><span class="sy1">></span>x<span class="sy4">;</span> <span class="kw1">if</span> <span class="br0">(</span>p<span class="br0">)</span> do_something<span class="br0">(</span>x<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span> <span class="kw4">void</span> f2<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw4">const</span> <span class="kw4">char</span> <span class="sy2">*</span>p <span class="sy1">=</span> <span class="kw2">NULL</span><span class="sy4">;</span> <span class="kw1">for</span> <span class="br0">(</span><span class="kw4">int</span> i <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span> str<span class="br0">[</span>i<span class="br0">]</span> <span class="sy3">!</span><span class="sy1">=</span> <span class="st0">'<span class="es5">\0</span>'</span><span class="sy4">;</span> i<span class="sy2">++</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">if</span> <span class="br0">(</span>str<span class="br0">[</span>i<span class="br0">]</span> <span class="sy1">==</span> <span class="st0">' '</span><span class="br0">)</span> <span class="br0">{</span> p <span class="sy1">=</span> str <span class="sy2">+</span> i<span class="sy4">;</span> <span class="kw1">break</span><span class="sy4">;</span> <span class="br0">}</span> <span class="br0">}</span> <span class="co1">// p is NULL if str doesn't have a space. If str always has a</span> <span class="co1">// a space then the condition (str[i] != '\0') would be redundant</span> <span class="kw1">return</span> p<span class="br0">[</span><span class="nu0">1</span><span class="br0">]</span><span class="sy4">;</span> <span class="br0">}</span> <span class="kw4">void</span> f3<span class="br0">(</span><span class="kw4">int</span> a<span class="br0">)</span> <span class="br0">{</span> <span class="kw4">struct</span> fred_t <span class="sy2">*</span>p <span class="sy1">=</span> <span class="kw2">NULL</span><span class="sy4">;</span> <span class="kw1">if</span> <span class="br0">(</span>a <span class="sy1">==</span> <span class="nu0">1</span><span class="br0">)</span> p <span class="sy1">=</span> fred1<span class="sy4">;</span> <span class="co1">// if a is not 1 then p is NULL</span> p<span class="sy2">-</span><span class="sy1">></span>x <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span> <span class="br0">}</span></pre> </div> <!-- .wrap --> </div> <!-- #content --> <?php include_once("../analyticstracking.php") ?> </body> </html>