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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Qt Toolkit - Qt Object Model</title><style type="text/css"><!--
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<h1 align=center> Qt Object Model</h1><br clear="all">
The standard C++ Object Model provides very efficient runtime support
of the object paradigm. On the negative side, its static nature shows
inflexibility in certain problem domains. Graphical User Interface
programming is one example that requires both runtime efficiency and a
high level of flexibility. Qt provides this, by combining the speed of
C++ with the flexibility of the Qt Object Model.
<p>
In addition to C++, Qt provides
<p>
<ul>
<li> a very powerful mechanism for seamless object
communication dubbed <a href="signalsandslots.html">signals and
slots</a>,
<li> queryable and designable <a href="properties.html">object
properties</a>,
<li> powerful <a href="eventsandfilters.html">events and event filters</a>,
<li> scoped <a href="i18n.html">string translation for internationalization</a>,
<li> sophisticated interval driven <a href="timers.html">timers</a>
that make it possible to elegantly integrate many tasks in an
event-driven GUI.
<li> hierarchical and queryable <a href="objecttrees.html">object
trees</a> that organize object ownership in a natural way.
<li> guarded pointers, <a href="qguardedptr.html">QGuardedPtr</a>, that are automatically
set to null when the referenced object is destroyed, unlike normal C++
pointers which become "dangling pointers" in that case.
</ul>
<p>
Many of these Qt features are implemented with standard C++
techniques, based on inheritance from <a href="qobject.html">QObject</a>. Others, like the
object communication mechanism and the dynamic property system,
require the <a href="metaobjects.html">Meta Object System</a> provided
by Qt's own <a href="moc.html">Meta Object Compiler (moc)</a>. Think
of the Meta Object System as a C++ extension that makes the language
better suited for true component GUI programming.
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<td>Copyright 2001 Trolltech<td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a>
<td align="right"><div align="right">Qt version 2.3.2</div>
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