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| 32 | <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>
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| 33 |
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| 34 |
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| 35 |
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| 36 | <p> The standard C++ Object Model provides very efficient runtime support
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| 37 | for the object paradigm. But the C++ Object Model's static nature is
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| 38 | inflexibile in certain problem domains. Graphical User Interface
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| 39 | programming is a domain that requires both runtime efficiency and a
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| 40 | high level of flexibility. Qt provides this, by combining the speed of
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| 41 | C++ with the flexibility of the Qt Object Model.
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| 42 | <p> Qt adds these features to C++:
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| 43 | <p> <ul>
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| 44 | <li> a very powerful mechanism for seamless object
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| 45 | communication called <a href="signalsandslots.html">signals and
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| 46 | slots</a>;
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| 47 | <li> queryable and designable <a href="properties.html">object
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| 48 | properties</a>;
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| 49 | <li> powerful <a href="eventsandfilters.html">events and event filters</a>,
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| 50 | <li> contextual <a href="i18n.html">string translation for internationalization</a>;
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| 51 | <li> sophisticated interval driven <a href="timers.html">timers</a>
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| 52 | that make it possible to elegantly integrate many tasks in an
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| 53 | event-driven GUI;
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| 54 | <li> hierarchical and queryable <a href="objecttrees.html">object
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| 55 | trees</a> that organize object ownership in a natural way;
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| 56 | <li> guarded pointers, <a href="qguardedptr.html">QGuardedPtr</a>, that are automatically
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| 57 | set to 0 when the referenced object is destroyed, unlike normal C++
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| 58 | pointers which become "dangling pointers" when their objects are destroyed.
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| 59 | </ul>
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| 60 | <p> Many of these Qt features are implemented with standard C++
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| 61 | techniques, based on inheritance from <a href="qobject.html">QObject</a>. Others, like the
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| 62 | object communication mechanism and the dynamic property system,
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| 63 | require the <a href="metaobjects.html">Meta Object System</a> provided
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| 64 | by Qt's own <a href="moc.html">Meta Object Compiler (moc)</a>.
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| 65 | <p> The Meta Object System is a C++ extension that makes the language
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| 66 | better suited to true component GUI programming. Although templates can
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| 67 | be used to extend C++, the Meta Object System provides benefits using
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| 68 | standard C++ that cannot be achieved with templates; see <a href="templates.html">Why doesn't Qt use templates for signals and
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| 69 | slots?</a>.
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| 70 | <p>
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| 71 | <!-- eof -->
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| 72 | <p><address><hr><div align=center>
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| 73 | <table width=100% cellspacing=0 border=0><tr>
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| 74 | <td>Copyright © 2007
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| 75 | <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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| 76 | <td align=right><div align=right>Qt 3.3.8</div>
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| 77 | </table></div></address></body>
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