<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Appendix A. The RefPtr smartpointer</title> <link rel="stylesheet" type="text/css" href="style.css"> <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> <link rel="home" href="index.html" title="Programming with gtkmm 3"> <link rel="up" href="index.html" title="Programming with gtkmm 3"> <link rel="prev" href="chapter-contributing.html" title="Chapter 32. Contributing"> <link rel="next" href="sec-refptr-dereferencing.html" title="Dereferencing"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr><th colspan="3" align="center">Appendix A. The RefPtr smartpointer</th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="chapter-contributing.html"><img src="icons/prev.png" alt="Prev"></a> </td> <th width="60%" align="center"> </th> <td width="20%" align="right"> <a accesskey="n" href="sec-refptr-dereferencing.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> </table> <hr> </div> <div class="appendix"> <div class="titlepage"><div><div><h1 class="title"> <a name="chapter-refptr"></a>Appendix A. The RefPtr smartpointer</h1></div></div></div> <div class="toc"> <p><b>Table of Contents</b></p> <ul class="toc"> <li><span class="sect1"><a href="chapter-refptr.html#sec-refptr-copying">Copying</a></span></li> <li><span class="sect1"><a href="sec-refptr-dereferencing.html">Dereferencing</a></span></li> <li><span class="sect1"><a href="sec-refptr-casting.html">Casting</a></span></li> <li><span class="sect1"><a href="sec-refptr-checking-for-null.html">Checking for null</a></span></li> <li><span class="sect1"><a href="sec-refptr-constness.html">Constness</a></span></li> </ul> </div> <p> <code class="classname">Glib::RefPtr</code> is a smartpointer. Specifically, it is a reference-counting smartpointer. You might be familiar with <code class="classname">std::auto_ptr<></code>, <code class="classname">std::unique_ptr<></code> and <code class="classname">std::shared_ptr<></code>, which are also smartpointers. <code class="classname">Glib::RefPtr<></code> is similar to <code class="classname">std::shared_ptr<></code>, which is also reference-counting. <code class="classname">Glib::RefPtr<></code> was introduced long before there was a reference-counting smartpointer in the C++ Standard Library. </p> <p><a class="ulink" href="http://developer.gnome.org/glibmm/2.58/classGlib_1_1RefPtr.html" target="_top">Reference</a></p> <p>A smartpointer acts much like a normal pointer. Here are a few examples.</p> <div class="sect1"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="sec-refptr-copying"></a>Copying</h2></div></div></div> <p> You can copy <code class="classname">RefPtr</code>s, just like normal pointers. But unlike normal pointers, you don't need to worry about deleting the underlying instance. </p> <p> </p> <pre class="programlisting"> Glib::RefPtr<Gdk::Pixbuf> refPixbuf = Gdk::Pixbuf::create_from_file(filename); Glib::RefPtr<Gdk::Pixbuf> refPixbuf2 = refPixbuf; </pre> <p> </p> <p> Of course this means that you can store <code class="classname">RefPtr</code>s in standard containers, such as <code class="classname">std::vector</code> or <code class="classname">std::list</code>.</p> <p> </p> <pre class="programlisting"> std::list< Glib::RefPtr<Gdk::Pixbuf> > listPixbufs; Glib::RefPtr<Gdk::Pixbuf> refPixbuf = Gdk::Pixbuf::create_from_file(filename); listPixbufs.push_back(refPixbuf); </pre> <p> </p> </div> </div> <div class="navfooter"> <hr> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"> <a accesskey="p" href="chapter-contributing.html"><img src="icons/prev.png" alt="Prev"></a> </td> <td width="20%" align="center"> </td> <td width="40%" align="right"> <a accesskey="n" href="sec-refptr-dereferencing.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> <tr> <td width="40%" align="left" valign="top">Chapter 32. Contributing </td> <td width="20%" align="center"><a accesskey="h" href="index.html"><img src="icons/home.png" alt="Home"></a></td> <td width="40%" align="right" valign="top"> Dereferencing</td> </tr> </table> </div> </body> </html>
