<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- xmlstreamlint.qdoc --> <title>XML Stream Lint Example | Qt XML 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtxml-index.html">Qt XML</a></td><td >XML Stream Lint Example</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtxml-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#basic-operation">Basic Operation</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">XML Stream Lint Example</h1> <span class="subtitle"></span> <!-- $$$xmlstreamlint-brief --> <p>A commandline tool reading from an input file and writing to the standard output file.</p> <!-- @@@xmlstreamlint --> <!-- $$$xmlstreamlint-description --> <div class="descr"> <a name="details"></a> <p>The XML Stream Lint example provides a simple command line utility that accepts a file name as its single argument and writes it to the standard output file.</p> <p>The specified file is parsed using an <a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a> object and written to the standard output file using an <a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a> object. If the file does not contain a well-formed XML document or the use of namespaces in the document is incorrect, a description of the error is printed to the standard error file and will appear in the console.</p> <a name="basic-operation"></a> <h2 id="basic-operation">Basic Operation</h2> <p>The main function of the example opens the file specified by the user for input (<code>inputFile</code>), and it uses <a href="../qtcore/qfile.html">QFile</a> to access the standard output file.</p> <p>Reading XML is handled by an instance of the <a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a> class, which operates on the input file object; writing is handled by an instance of <a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a> operating on the output file object:</p> <pre class="cpp"> <span class="type"><a href="../qtcore/qxmlstreamreader.html">QXmlStreamReader</a></span> reader(<span class="operator">&</span>inputFile); <span class="type"><a href="../qtcore/qxmlstreamwriter.html">QXmlStreamWriter</a></span> writer(<span class="operator">&</span>outputFile); </pre> <p>The work of parsing and rewriting the XML is done in a while loop, and is driven by input from the reader:</p> <pre class="cpp"> <span class="keyword">while</span> (<span class="operator">!</span>reader<span class="operator">.</span>atEnd()) { reader<span class="operator">.</span>readNext(); <span class="keyword">if</span> (reader<span class="operator">.</span>error()) { errorStream <span class="operator"><</span><span class="operator"><</span> XmlStreamLint<span class="operator">::</span>tr( <span class="string">"Error: %1 in file %2 at line %3, column %4.\n"</span>)<span class="operator">.</span>arg( reader<span class="operator">.</span>errorString()<span class="operator">,</span> inputFilePath<span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>number(reader<span class="operator">.</span>lineNumber())<span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span><span class="operator">::</span>number(reader<span class="operator">.</span>columnNumber())); <span class="keyword">return</span> ParseFailure; </pre> <p>If more input is available, the next token from the input file is read and parsed. If an error occurred, information is written to the standard error file via a stream, and the example exits by returning a non-zero value from the main function.</p> <pre class="cpp"> } <span class="keyword">else</span> writer<span class="operator">.</span>writeCurrentToken(reader); } </pre> <p>For valid input, the writer is fed the current token from the reader, and this is written to the output file that was specified when it was constructed.</p> <p>When there is no more input, the loop terminates, and the example can exit successfully.</p> <p>Files:</p> <ul> <li><a href="qtxml-xmlstreamlint-main-cpp.html">xmlstreamlint/main.cpp</a></li> <li><a href="qtxml-xmlstreamlint-xmlstreamlint-pro.html">xmlstreamlint/xmlstreamlint.pro</a></li> </ul> </div> <!-- @@@xmlstreamlint --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>