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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Qt Object Model</h1>


<p> The standard C++ Object Model provides very efficient runtime support
for the object paradigm. But the C++ Object Model's static nature is
inflexibile in certain problem domains. Graphical User Interface
programming is a domain 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> Qt adds these features to C++:
<p> <ul>
<li> a very powerful mechanism for seamless object
communication called <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> contextual <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 0 when the referenced object is destroyed, unlike normal C++
pointers which become "dangling pointers" when their objects are destroyed.
</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>. 
<p> The Meta Object System is a C++ extension that makes the language
better suited to true component GUI programming. Although templates can
be used to extend C++, the Meta Object System provides benefits using
standard C++ that cannot be achieved with templates; see <a href="templates.html">Why doesn't Qt use templates for signals and
slots?</a>.
<p> 
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<td align=right><div align=right>Qt 3.3.8</div>
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