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<title>Qt 4.8: XML Stream Lint Example</title>
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<li class="level1"><a href="#basic-operation">Basic Operation</a></li>
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<h1 class="title">XML Stream Lint Example</h1>
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<li><a href="xml-xmlstreamlint-main-cpp.html">xml/xmlstreamlint/main.cpp</a></li>
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<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>The specified file is parsed using an <a href="qxmlstreamreader.html">QXmlStreamReader</a> object and written to the standard output file using an <a href="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>Basic Operation</h2>
<p>The main function of the example opens the file specified by the user for input (<tt>inputFile</tt>), and it uses <a href="qfile.html">QFile</a> to access the standard output file.</p>
<p>Reading XML is handled by an instance of the <a href="qxmlstreamreader.html">QXmlStreamReader</a> class, which operates on the input file object; writing is handled by an instance of <a href="qxmlstreamwriter.html">QXmlStreamWriter</a> operating on the output file object:</p>
<pre class="cpp"> <span class="type"><a href="qxmlstreamreader.html">QXmlStreamReader</a></span> reader(<span class="operator">&</span>inputFile);
<span class="type"><a href="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="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="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>
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