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1<?xml version="1.0" encoding="iso-8859-1"?> 2<!DOCTYPE html 3 PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd"> 4<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 5<!-- qtservice-2.6_1-opensource/src/qtservice.cpp --> 6<head> 7 <title>QtService Class Reference</title> 8 <link href="classic.css" rel="stylesheet" type="text/css" /> 9</head> 10<body> 11<table border="0" cellpadding="0" cellspacing="0" width="100%"> 12<tr> 13<td align="left" valign="top" width="32"><img src="images/qt-logo.png" align="left" width="57" height="67" border="0" /></td> 14<td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a></td> 15</tr></table><h1 class="title">QtService Class Reference</h1> 16<p>The QtService is a convenient template class that allows you to create a service for a particular application type. <a href="#details">More...</a></p> 17<pre> #include <QtService></pre><p>Inherits <a href="qtservicebase.html">QtServiceBase</a>.</p> 18<ul> 19<li><a href="qtservice-members.html">List of all members, including inherited members</a></li> 20</ul> 21<a name="public-functions"></a> 22<h3>Public Functions</h3> 23<ul> 24<li><div class="fn"></div><b><a href="qtservice.html#QtService">QtService</a></b> ( int <i>argc</i>, char ** <i>argv</i>, const QString & <i>name</i> )</li> 25<li><div class="fn"></div><b><a href="qtservice.html#dtor.QtService">~QtService</a></b> ()</li> 26</ul> 27<ul> 28<li><div class="fn"></div>9 public functions inherited from <a href="qtservicebase.html#public-functions">QtServiceBase</a></li> 29</ul> 30<a name="protected-functions"></a> 31<h3>Protected Functions</h3> 32<ul> 33<li><div class="fn"></div>Application * <b><a href="qtservice.html#application">application</a></b> () const</li> 34</ul> 35<ul> 36<li><div class="fn"></div>7 protected functions inherited from <a href="qtservicebase.html#protected-functions">QtServiceBase</a></li> 37</ul> 38<h3>Additional Inherited Members</h3> 39<ul> 40<li><div class="fn"></div>1 static public member inherited from <a href="qtservicebase.html#static-public-members">QtServiceBase</a></li> 41</ul> 42<a name="details"></a> 43<hr /> 44<h2>Detailed Description</h2> 45<p>The QtService is a convenient template class that allows you to create a service for a particular application type.</p> 46<p>A Windows service or Unix daemon (a "service"), is a program that runs "in the background" independently of whether a user is logged in or not. A service is often set up to start when the machine boots up, and will typically run continuously as long as the machine is on.</p> 47<p>Services are usually non-interactive console applications. User interaction, if required, is usually implemented in a separate, normal GUI application that communicates with the service through an IPC channel. For simple communication, <a href="qtservicecontroller.html#sendCommand">QtServiceController::sendCommand</a>() and <a href="qtservicebase.html#processCommand">QtService::processCommand</a>() may be used, possibly in combination with a shared settings file. For more complex, interactive communication, a custom IPC channel should be used, e.g. based on Qt's networking classes. (In certain circumstances, a service may provide a GUI itself, ref. the "interactive" example documentation).</p> 48<p><b>Note:</b> On Unix systems, this class relies on facilities provided by the <a href="http://qt.nokia.com/doc/4.5/qtnetwork.html">QtNetwork</a> module, provided as part of the Qt Open Source Edition and certain <a href="http://qt.nokia.com/doc/4.5/commercialeditions.html">Qt Commercial Editions</a>.</p> 49<p>The QtService class functionality is inherited from <a href="qtservicebase.html">QtServiceBase</a>, but in addition the QtService class binds an instance of <a href="qtservicebase.html">QtServiceBase</a> with an application type.</p> 50<p>Typically, you will create a service by subclassing the QtService template class. For example:</p> 51<pre> class MyService : public QtService<QApplication> 52 { 53 public: 54 MyService(int argc, char **argv); 55 ~MyService(); 56 57 protected: 58 void start(); 59 void stop(); 60 void pause(); 61 void resume(); 62 void processCommand(int code); 63 };</pre> 64<p>The application type can be <a href="http://qt.nokia.com/doc/4.5/qcoreapplication.html">QCoreApplication</a> for services without GUI, <a href="http://qt.nokia.com/doc/4.5/qapplication.html">QApplication</a> for services with GUI or you can use your own custom application type.</p> 65<p>You must reimplement the <a href="qtservicebase.html#start">QtServiceBase::start</a>() function to perform the service's work. Usually you create some main object on the heap which is the heart of your service.</p> 66<p>In addition, you might want to reimplement the <a href="qtservicebase.html#pause">QtServiceBase::pause</a>(), <a href="qtservicebase.html#processCommand">QtServiceBase::processCommand</a>(), <a href="qtservicebase.html#resume">QtServiceBase::resume</a>() and <a href="qtservicebase.html#stop">QtServiceBase::stop</a>() to intervene the service's process on controller requests. You can control any given service using an instance of the <a href="qtservicecontroller.html">QtServiceController</a> class which also allows you to control services from separate applications. The mentioned functions are all virtual and won't do anything unless they are reimplemented.</p> 67<p>Your custom service is typically instantiated in the application's main function. Then the main function will call your service's <a href="qtservicebase.html#exec">exec</a>() function, and return the result of that call. For example:</p> 68<pre> int main(int argc, char **argv) 69 { 70 MyService service(argc, argv); 71 return service.exec(); 72 }</pre> 73<p>When the <a href="qtservicebase.html#exec">exec</a>() function is called, it will parse the <a href="qtservicebase.html#servicespecificarguments">service specific arguments</a> passed in <tt>argv</tt>, perform the required actions, and exit.</p> 74<p>If none of the arguments is recognized as service specific, <a href="qtservicebase.html#exec">exec</a>() will first call the <a href="qtservicebase.html#createApplication">createApplication</a>() function, then <a href="qtservicebase.html#executeApplication">executeApplication</a>() and finally the <a href="qtservicebase.html#start">start</a>() function. In the end, <a href="qtservicebase.html#exec">exec</a>() returns while the service continues in its own process waiting for commands from the service controller.</p> 75<p>See also <a href="qtservicebase.html">QtServiceBase</a> and <a href="qtservicecontroller.html">QtServiceController</a>.</p> 76<hr /> 77<h2>Member Function Documentation</h2> 78<h3 class="fn"><a name="QtService"></a>QtService::QtService ( int <i>argc</i>, char ** <i>argv</i>, const <a href="http://qt.nokia.com/doc/4.5/qstring.html">QString</a> & <i>name</i> )</h3> 79<p>Constructs a <a href="qtservice.html">QtService</a> object called <i>name</i>. The <i>argc</i> and <i>argv</i> parameters are parsed after the <a href="qtservicebase.html#exec">exec</a>() function has been called. Then they are passed to the application's constructor.</p> 80<p>There can only be one <a href="qtservice.html">QtService</a> object in a process.</p> 81<p>See also <a href="qtservicebase.html#QtServiceBase">QtServiceBase</a>().</p> 82<h3 class="fn"><a name="dtor.QtService"></a>QtService::~QtService ()</h3> 83<p>Destroys the service object.</p> 84<h3 class="fn"><a name="application"></a>Application * QtService::application () const <tt> [protected]</tt></h3> 85<p>Returns a pointer to the application object.</p> 86<p /><address><hr /><div align="center"> 87<table width="100%" cellspacing="0" border="0"><tr class="address"> 88<td width="30%" align="left">Copyright © 2009 Nokia Corporation and/or its subsidiary(-ies)</td> 89<td width="40%" align="center"><a href="http://qt.nokia.com/doc/trademarks.html">Trademarks</a></td> 90<td width="30%" align="right"><div align="right">Qt Solutions</div></td> 91</tr></table></div></address></body> 92</html>