<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!-- /home/reggie/tmp/qt-3.1-reggie-23625/qt-x11-free-3.1.1/src/tools/qptrcollection.cpp:40 --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>QPtrCollection Class</title> <style type="text/css"><!-- h3.fn,span.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>QPtrCollection Class Reference</h1> <p>The QPtrCollection class is the base class of most pointer-based Qt collections. <a href="#details">More...</a> <p>All the functions in this class are <a href="threads.html#reentrant">reentrant</a> when Qt is built with thread support.</p> <p><tt>#include <<a href="qptrcollection-h.html">qptrcollection.h</a>></tt> <p>Inherited by <a href="qasciidict.html">QAsciiDict</a>, <a href="qcache.html">QCache</a>, <a href="qdict.html">QDict</a>, <a href="qintdict.html">QIntDict</a>, <a href="qptrlist.html">QPtrList</a>, <a href="qptrdict.html">QPtrDict</a>, and <a href="qptrvector.html">QPtrVector</a>. <p><a href="qptrcollection-members.html">List of all member functions.</a> <h2>Public Members</h2> <ul> <li><div class=fn>bool <a href="#autoDelete"><b>autoDelete</b></a> () const</div></li> <li><div class=fn>void <a href="#setAutoDelete"><b>setAutoDelete</b></a> ( bool enable )</div></li> <li><div class=fn>virtual uint <a href="#count"><b>count</b></a> () const = 0</div></li> <li><div class=fn>virtual void <a href="#clear"><b>clear</b></a> () = 0</div></li> <li><div class=fn>typedef void * <a href="#Item"><b>Item</b></a></div></li> </ul> <h2>Protected Members</h2> <ul> <li><div class=fn><a href="#QPtrCollection"><b>QPtrCollection</b></a> ()</div></li> <li><div class=fn><a href="#QPtrCollection-2"><b>QPtrCollection</b></a> ( const QPtrCollection & source )</div></li> <li><div class=fn>virtual <a href="#~QPtrCollection"><b>~QPtrCollection</b></a> ()</div></li> <li><div class=fn>virtual Item <a href="#newItem"><b>newItem</b></a> ( Item d )</div></li> <li><div class=fn>virtual void <a href="#deleteItem"><b>deleteItem</b></a> ( Item d ) = 0</div></li> </ul> <hr><a name="details"></a><h2>Detailed Description</h2> The QPtrCollection class is the base class of most pointer-based Qt collections. <p> <p> The QPtrCollection class is an abstract base class for the Qt <a href="collection.html">collection classes</a> <a href="qdict.html">QDict</a>, <a href="qptrlist.html">QPtrList</a>, etc. Qt also includes value based collections, e.g. <a href="qvaluelist.html">QValueList</a>, <a href="qmap.html">QMap</a>, etc. <p> A QPtrCollection only knows about the number of objects in the collection and the deletion strategy (see <a href="#setAutoDelete">setAutoDelete</a>()). <p> A collection is implemented using the <a href="#Item">Item</a> (generic collection item) type, which is a <tt>void*</tt>. The template classes that create the real collections cast the <a href="#Item">Item</a> to the required type. <p>See also <a href="collection.html">Collection Classes</a> and <a href="tools.html">Non-GUI Classes</a>. <hr><h2>Member Type Documentation</h2> <h3 class=fn><a name="Item"></a>QPtrCollection::Item</h3> <p> This type is the generic "item" in a QPtrCollection. <hr><h2>Member Function Documentation</h2> <h3 class=fn><a name="QPtrCollection"></a>QPtrCollection::QPtrCollection ()<tt> [protected]</tt> </h3> <p> Constructs a collection. The constructor is protected because QPtrCollection is an abstract class. <h3 class=fn><a name="QPtrCollection-2"></a>QPtrCollection::QPtrCollection ( const <a href="qptrcollection.html">QPtrCollection</a> & source )<tt> [protected]</tt> </h3> <p> Constructs a copy of <em>source</em> with <a href="#autoDelete">autoDelete</a>() set to FALSE. The constructor is protected because QPtrCollection is an abstract class. <p> Note that if <em>source</em> has autoDelete turned on, copying it will risk memory leaks, reading freed memory, or both. <h3 class=fn><a name="~QPtrCollection"></a>QPtrCollection::~QPtrCollection ()<tt> [virtual protected]</tt> </h3> <p> Destroys the collection. The destructor is protected because QPtrCollection is an abstract class. <h3 class=fn>bool <a name="autoDelete"></a>QPtrCollection::autoDelete () const </h3> <p> Returns the setting of the auto-delete option. The default is FALSE. <p> <p>See also <a href="#setAutoDelete">setAutoDelete</a>(). <h3 class=fn>void <a name="clear"></a>QPtrCollection::clear ()<tt> [pure virtual]</tt> </h3> <p> Removes all objects from the collection. The objects will be deleted if auto-delete has been enabled. <p> <p>See also <a href="#setAutoDelete">setAutoDelete</a>(). <p>Reimplemented in <a href="qasciidict.html#clear">QAsciiDict</a>, <a href="qcache.html#clear">QCache</a>, <a href="qdict.html#clear">QDict</a>, <a href="qintdict.html#clear">QIntDict</a>, <a href="qptrlist.html#clear">QPtrList</a>, <a href="qptrdict.html#clear">QPtrDict</a>, and <a href="qptrvector.html#clear">QPtrVector</a>. <h3 class=fn>uint <a name="count"></a>QPtrCollection::count () const<tt> [pure virtual]</tt> </h3> <p> Returns the number of objects in the collection. <p>Reimplemented in <a href="qasciidict.html#count">QAsciiDict</a>, <a href="qcache.html#count">QCache</a>, <a href="qdict.html#count">QDict</a>, <a href="qintdict.html#count">QIntDict</a>, <a href="qptrlist.html#count">QPtrList</a>, <a href="qptrdict.html#count">QPtrDict</a>, and <a href="qptrvector.html#count">QPtrVector</a>. <h3 class=fn>void <a name="deleteItem"></a>QPtrCollection::deleteItem ( <a href="qptrcollection.html#Item">Item</a> d )<tt> [pure virtual protected]</tt> </h3> <p> Reimplement this function if you want to be able to delete items. <p> Deletes an item that is about to be removed from the collection. <p> This function has to reimplemented in the collection template classes, and should <em>only</em> delete item <em>d</em> if auto-delete has been enabled. <p> <b>Warning:</b> If you reimplement this function you must also reimplement the destructor and call the virtual function <a href="#clear">clear</a>() from your destructor. This is due to the way virtual functions and destructors work in C++: Virtual functions in derived classes cannot be called from a destructor. If you do not do this, your <a href="#deleteItem">deleteItem</a>() function will not be called when the container is destroyed. <p> <p>See also <a href="#newItem">newItem</a>() and <a href="#setAutoDelete">setAutoDelete</a>(). <h3 class=fn><a href="qptrcollection.html#Item">Item</a> <a name="newItem"></a>QPtrCollection::newItem ( <a href="qptrcollection.html#Item">Item</a> d )<tt> [virtual protected]</tt> </h3> Virtual function that creates a copy of an object that is about to be inserted into the collection. <p> The default implementation returns the <em>d</em> pointer, i.e. no copy is made. <p> This function is seldom reimplemented in the collection template classes. It is not common practice to make a copy of something that is being inserted. <p> <p>See also <a href="#deleteItem">deleteItem</a>(). <h3 class=fn>void <a name="setAutoDelete"></a>QPtrCollection::setAutoDelete ( bool enable ) </h3> <p> Sets the collection to auto-delete its contents if <em>enable</em> is TRUE and to never delete them if <em>enable</em> is FALSE. <p> If auto-deleting is turned on, all the items in a collection are deleted when the collection itself is deleted. This is convenient if the collection has the only pointer to the items. <p> The default setting is FALSE, for safety. If you turn it on, be careful about copying the collection - you might find yourself with two collections deleting the same items. <p> Note that the auto-delete setting may also affect other functions in subclasses. For example, a subclass that has a remove() function will remove the item from its data structure, and if auto-delete is enabled, will also delete the item. <p> <p>See also <a href="#autoDelete">autoDelete</a>(). <p>Examples: <a href="scribble-example.html#x941">scribble/scribble.cpp</a> and <a href="bigtable-example.html#x1461">table/bigtable/main.cpp</a>. <!-- eof --> <hr><p> This file is part of the <a href="index.html">Qt toolkit</a>. Copyright © 1995-2002 <a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center> <table width=100% cellspacing=0 border=0><tr> <td>Copyright © 2002 <a href="http://www.trolltech.com">Trolltech</a><td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a> <td align=right><div align=right>Qt version 3.1.1</div> </table></div></address></body> </html>