<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/examples/process/process.doc:5 --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Starting processes with IO redirection</title> <style type="text/css"><!-- fn { margin-left: 1cm; text-indent: -1cm; } a:link { color: #004faf; text-decoration: none } a:visited { color: #672967; text-decoration: none } body { background: #ffffff; color: black; } --></style> </head> <body> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr bgcolor="#E5E5E5"> <td valign=center> <a href="index.html"> <font color="#004faf">Home</font></a> | <a href="classes.html"> <font color="#004faf">All Classes</font></a> | <a href="mainclasses.html"> <font color="#004faf">Main Classes</font></a> | <a href="annotated.html"> <font color="#004faf">Annotated</font></a> | <a href="groups.html"> <font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"> <font color="#004faf">Functions</font></a> </td> <td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Starting processes with IO redirection</h1> <p> <p> This example shows you how to start other processes with Qt and how IO redirection is done. The example tries to start the uic (a tool that comes with the Qt Designer) on a certain ui file and displays the output of the command. <p> <hr> <p> Implementation (process.cpp): <p> <pre>/**************************************************************************** ** $Id: qt/process.cpp 3.3.8 edited Jan 11 14:37 $ ** ** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved. ** ** This file is part of an example program for Qt. This example ** program may be used, distributed and modified without limitation. ** *****************************************************************************/ #include <<a href="qobject-h.html">qobject.h</a>> #include <<a href="qprocess-h.html">qprocess.h</a>> #include <<a href="qvbox-h.html">qvbox.h</a>> #include <<a href="qtextview-h.html">qtextview.h</a>> #include <<a href="qpushbutton-h.html">qpushbutton.h</a>> #include <<a href="qapplication-h.html">qapplication.h</a>> #include <<a href="qmessagebox-h.html">qmessagebox.h</a>> #include <stdlib.h> class UicManager : public <a href="qvbox.html">QVBox</a> { <a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a> public: UicManager(); ~UicManager() {} public slots: void readFromStdout(); void scrollToTop(); private: <a href="qprocess.html">QProcess</a> *proc; <a href="qtextview.html">QTextView</a> *output; <a href="qpushbutton.html">QPushButton</a> *quitButton; }; <a name="f204"></a>UicManager::UicManager() { // Layout output = new <a href="qtextview.html">QTextView</a>( this ); quitButton = new <a href="qpushbutton.html">QPushButton</a>( <a href="qobject.html#tr">tr</a>("Quit"), this ); <a href="qobject.html#connect">connect</a>( quitButton, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), qApp, SLOT(<a href="qapplication.html#quit">quit</a>()) ); <a href="qwidget.html#resize">resize</a>( 500, 500 ); // QProcess related code proc = new <a href="qprocess.html">QProcess</a>( this ); // Set up the command and arguments. // On the command line you would do: // uic -tr <a href="i18n.html#i18n">i18n</a> "small_dialog.ui" <a name="x97"></a> proc-><a href="qprocess.html#addArgument">addArgument</a>( "uic" ); proc-><a href="qprocess.html#addArgument">addArgument</a>( "-tr" ); proc-><a href="qprocess.html#addArgument">addArgument</a>( "i18n" ); proc-><a href="qprocess.html#addArgument">addArgument</a>( "small_dialog.ui" ); <a name="x100"></a> <a href="qobject.html#connect">connect</a>( proc, SIGNAL(<a href="qprocess.html#readyReadStdout">readyReadStdout</a>()), this, SLOT(readFromStdout()) ); <a name="x98"></a> <a href="qobject.html#connect">connect</a>( proc, SIGNAL(<a href="qprocess.html#processExited">processExited</a>()), this, SLOT(scrollToTop()) ); <a name="x101"></a> if ( !proc-><a href="qprocess.html#start">start</a>() ) { // error handling <a name="x96"></a> QMessageBox::<a href="qmessagebox.html#critical">critical</a>( 0, <a href="qobject.html#tr">tr</a>("Fatal error"), <a href="qobject.html#tr">tr</a>("Could not start the uic command."), <a href="qobject.html#tr">tr</a>("Quit") ); exit( -1 ); } } void <a name="f205"></a>UicManager::readFromStdout() { // Read and process the data. // Bear in mind that the data might be output in chunks. <a name="x99"></a><a name="x103"></a> output-><a href="qtextedit.html#append">append</a>( proc-><a href="qprocess.html#readStdout">readStdout</a>() ); } void <a name="f206"></a>UicManager::scrollToTop() { <a name="x102"></a> output-><a href="qscrollview.html#setContentsPos">setContentsPos</a>( 0, 0 ); } int main( int argc, char **argv ) { <a href="qapplication.html">QApplication</a> a( argc, argv ); UicManager manager; a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &manager ); manager.<a href="qwidget.html#show">show</a>(); return a.<a href="qapplication.html#exec">exec</a>(); } #include "process.moc" </pre> <p>See also <a href="qprocess-examples.html">QProcess Examples</a>. <!-- eof --> <p><address><hr><div align=center> <table width=100% cellspacing=0 border=0><tr> <td>Copyright © 2007 <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> <td align=right><div align=right>Qt 3.3.8</div> </table></div></address></body> </html>