src/parsec/disk-image/parsec/parsec-benchmark/pkgs/libs/glib/src/docs/reference/gobject/html/howto-interface.html - public/gem5-resources - Git at Google

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <title>How to define and implement interfaces</title>
 <meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
 <link rel="home" href="index.html" title="GObject Reference Manual">
 <link rel="up" href="pt02.html" title="Part IV. Tutorial">
 <link rel="prev" href="howto-gobject-chainup.html" title="Chaining up">
 <link rel="next" href="howto-interface-implement.html" title="How To define implement an Interface?">
 <meta name="generator" content="GTK-Doc V1.14 (XML mode)">
 <link rel="stylesheet" href="style.css" type="text/css">
 </head>
 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
 <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle">
 <td><a accesskey="p" href="howto-gobject-chainup.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
 <td><a accesskey="u" href="pt02.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
 <td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
 <th width="100%" align="center">GObject Reference Manual</th>
 <td><a accesskey="n" href="howto-interface-implement.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
 </tr></table>
 <div class="chapter" title="How to define and implement interfaces">
 <div class="titlepage"><div><div><h2 class="title">
 <a name="howto-interface"></a>How to define and implement interfaces</h2></div></div></div>
 <div class="toc"><dl>
 <dt><span class="sect1"><a href="howto-interface.html#howto-interface-define">How to define interfaces</a></span></dt>
 <dt><span class="sect1"><a href="howto-interface-implement.html">How To define implement an Interface?</a></span></dt>
 <dt><span class="sect1"><a href="ch06s03.html">Interface definition prerequisites</a></span></dt>
 <dt><span class="sect1"><a href="howto-interface-properties.html">Interface Properties</a></span></dt>
 </dl></div>
 <div class="sect1" title="How to define interfaces">
 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
 <a name="howto-interface-define"></a>How to define interfaces</h2></div></div></div>
 <p>
     The bulk of interface definition has already been shown in <a class="xref" href="gtype-non-instantiable-classed.html" title="Non-instantiable classed types: interfaces">the section called “Non-instantiable classed types: interfaces”</a>
     but I feel it is needed to show exactly how to create an interface.
   </p>
 <p>
     As above, the first step is to get the header right:
 </p>
 <pre class="programlisting">
 #ifndef __MAMAN_IBAZ_H__
 #define __MAMAN_IBAZ_H__

 #include &lt;glib-object.h&gt;

 #define MAMAN_TYPE_IBAZ                 (maman_ibaz_get_type ())
 #define MAMAN_IBAZ(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), MAMAN_TYPE_IBAZ, MamanIbaz))
 #define MAMAN_IS_IBAZ(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), MAMAN_TYPE_IBAZ))
 #define MAMAN_IBAZ_GET_INTERFACE(inst)  (G_TYPE_INSTANCE_GET_INTERFACE ((inst), MAMAN_TYPE_IBAZ, MamanIbazInterface))


 typedef struct _MamanIbaz               MamanIbaz; /* dummy object */
 typedef struct _MamanIbazInterface      MamanIbazInterface;

 struct _MamanIbazInterface
 {
   GTypeInterface parent_iface;

   void (*do_action) (MamanIbaz *self);
 };

 GType maman_ibaz_get_type (void);

 void maman_ibaz_do_action (MamanIbaz *self);

 #endif /* __MAMAN_IBAZ_H__ */
 </pre>
 <p>
     This code is the same as the code for a normal <span class="type"><a class="link" href="gobject-Type-Information.html#GType" title="GType">GType</a></span>
     which derives from a <span class="type"><a class="link" href="gobject-The-Base-Object-Type.html#GObject">GObject</a></span> except for a few details:
     </p>
 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
 <li class="listitem"><p>
         The <code class="function">_GET_CLASS</code> macro is called <code class="function">_GET_INTERFACE</code>
                   and not implemented with <code class="function">G_TYPE_INSTANCE_GET_CLASS</code>
                   but with <code class="function">G_TYPE_INSTANCE_GET_INTERFACE</code>.
       </p></li>
 <li class="listitem"><p>
         The instance type, <span class="type">MamanIbaz</span> is not fully defined: it is
         used merely as an abstract type which represents an instance of
         whatever object which implements the interface.
       </p></li>
 <li class="listitem"><p>
         The parent of the <span class="type">MamanIbazInterface</span> is not
         <span class="type">GObjectClass</span> but <span class="type">GTypeInterface</span>.
       </p></li>
 </ul></div>
 <p>
   </p>
 <p>
     The implementation of the <span class="type">MamanIbaz</span> type itself is trivial:
     </p>
 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
 <li class="listitem"><p><code class="function">maman_ibaz_get_type</code> registers the
        type in the type system.
        </p></li>
 <li class="listitem"><p><code class="function">maman_ibaz_base_init</code> is expected
       to register the interface's signals if there are any (we will see a bit
       (later how to use them). Make sure to use a static local boolean variable
       to make sure not to run the initialization code twice (as described in
       <a class="xref" href="gtype-non-instantiable-classed.html#gtype-non-instantiable-classed-init" title="Interface Initialization">the section called “Interface Initialization”</a>,
       <code class="function">base_init</code> is run once for each interface implementation
       instantiation)</p></li>
 <li class="listitem"><p><code class="function">maman_ibaz_do_action</code> dereferences
       the class structure to access its associated class function and calls it.
       </p></li>
 </ul></div>
 <p>
 </p>
 <pre class="programlisting">
 static void
 maman_ibaz_base_init (gpointer g_class)
 {
   static gboolean is_initialized = FALSE;

   if (!is_initialized)
     {
       /* add properties and signals to the interface here */

       is_initialized = TRUE;
     }
 }

 GType
 maman_ibaz_get_type (void)
 {
   static GType iface_type = 0;
   if (iface_type == 0)
     {
       static const GTypeInfo info = {
         sizeof (MamanIbazInterface),
         maman_ibaz_base_init,   /* base_init */
         NULL,   /* base_finalize */
       };

       iface_type = g_type_register_static (G_TYPE_INTERFACE, "MamanIbaz",
                                            &amp;info, 0);
     }

   return iface_type;
 }

 void
 maman_ibaz_do_action (MamanIbaz *self)
 {
   g_return_if_fail (MAMAN_IS_IBAZ (self));

   MAMAN_IBAZ_GET_INTERFACE (self)-&gt;do_action (self);
 }
 </pre>
 <p>
     </p>
 </div>
 </div>
 <div class="footer">
 <hr>
           Generated by GTK-Doc V1.14</div>
 </body>
 </html>
	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
	<html>
	<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
	<title>How to define and implement interfaces</title>
	<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
	<link rel="home" href="index.html" title="GObject Reference Manual">
	<link rel="up" href="pt02.html" title="Part IV. Tutorial">
	<link rel="prev" href="howto-gobject-chainup.html" title="Chaining up">
	<link rel="next" href="howto-interface-implement.html" title="How To define implement an Interface?">
	<meta name="generator" content="GTK-Doc V1.14 (XML mode)">
	<link rel="stylesheet" href="style.css" type="text/css">
	</head>
	<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
	<table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle">
	<td><a accesskey="p" href="howto-gobject-chainup.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td>
	<td><a accesskey="u" href="pt02.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td>
	<td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td>
	<th width="100%" align="center">GObject Reference Manual</th>
	<td><a accesskey="n" href="howto-interface-implement.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
	</tr></table>
	<div class="chapter" title="How to define and implement interfaces">
	<div class="titlepage"><div><div><h2 class="title">
	<a name="howto-interface"></a>How to define and implement interfaces</h2></div></div></div>
	<div class="toc"><dl>
	<dt><span class="sect1"><a href="howto-interface.html#howto-interface-define">How to define interfaces</a></span></dt>
	<dt><span class="sect1"><a href="howto-interface-implement.html">How To define implement an Interface?</a></span></dt>
	<dt><span class="sect1"><a href="ch06s03.html">Interface definition prerequisites</a></span></dt>
	<dt><span class="sect1"><a href="howto-interface-properties.html">Interface Properties</a></span></dt>
	</dl></div>
	<div class="sect1" title="How to define interfaces">
	<div class="titlepage"><div><div><h2 class="title" style="clear: both">
	<a name="howto-interface-define"></a>How to define interfaces</h2></div></div></div>
	<p>
	The bulk of interface definition has already been shown in <a class="xref" href="gtype-non-instantiable-classed.html" title="Non-instantiable classed types: interfaces">the section called “Non-instantiable classed types: interfaces”</a>
	but I feel it is needed to show exactly how to create an interface.
	</p>
	<p>
	As above, the first step is to get the header right:
	</p>
	<pre class="programlisting">
	#ifndef __MAMAN_IBAZ_H__
	#define __MAMAN_IBAZ_H__

	#include <glib-object.h>

	#define MAMAN_TYPE_IBAZ (maman_ibaz_get_type ())
	#define MAMAN_IBAZ(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), MAMAN_TYPE_IBAZ, MamanIbaz))
	#define MAMAN_IS_IBAZ(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), MAMAN_TYPE_IBAZ))
	#define MAMAN_IBAZ_GET_INTERFACE(inst) (G_TYPE_INSTANCE_GET_INTERFACE ((inst), MAMAN_TYPE_IBAZ, MamanIbazInterface))


	typedef struct _MamanIbaz MamanIbaz; /* dummy object */
	typedef struct _MamanIbazInterface MamanIbazInterface;

	struct _MamanIbazInterface
	{
	GTypeInterface parent_iface;

	void (do_action) (MamanIbaz self);
	};

	GType maman_ibaz_get_type (void);

	void maman_ibaz_do_action (MamanIbaz *self);

	#endif /* __MAMAN_IBAZ_H__ */
	</pre>
	<p>
	This code is the same as the code for a normal <span class="type"><a class="link" href="gobject-Type-Information.html#GType" title="GType">GType</a></span>
	which derives from a <span class="type"><a class="link" href="gobject-The-Base-Object-Type.html#GObject">GObject</a></span> except for a few details:
	</p>
	<div class="itemizedlist"><ul class="itemizedlist" type="disc">
	<li class="listitem"><p>
	The <code class="function">_GET_CLASS</code> macro is called <code class="function">_GET_INTERFACE</code>
	and not implemented with <code class="function">G_TYPE_INSTANCE_GET_CLASS</code>
	but with <code class="function">G_TYPE_INSTANCE_GET_INTERFACE</code>.
	</p></li>
	<li class="listitem"><p>
	The instance type, <span class="type">MamanIbaz</span> is not fully defined: it is
	used merely as an abstract type which represents an instance of
	whatever object which implements the interface.
	</p></li>
	<li class="listitem"><p>
	The parent of the <span class="type">MamanIbazInterface</span> is not
	<span class="type">GObjectClass</span> but <span class="type">GTypeInterface</span>.
	</p></li>
	</ul></div>
	<p>
	</p>
	<p>
	The implementation of the <span class="type">MamanIbaz</span> type itself is trivial:
	</p>
	<div class="itemizedlist"><ul class="itemizedlist" type="disc">
	<li class="listitem"><p><code class="function">maman_ibaz_get_type</code> registers the
	type in the type system.
	</p></li>
	<li class="listitem"><p><code class="function">maman_ibaz_base_init</code> is expected
	to register the interface's signals if there are any (we will see a bit
	(later how to use them). Make sure to use a static local boolean variable
	to make sure not to run the initialization code twice (as described in
	<a class="xref" href="gtype-non-instantiable-classed.html#gtype-non-instantiable-classed-init" title="Interface Initialization">the section called “Interface Initialization”</a>,
	<code class="function">base_init</code> is run once for each interface implementation
	instantiation)</p></li>
	<li class="listitem"><p><code class="function">maman_ibaz_do_action</code> dereferences
	the class structure to access its associated class function and calls it.
	</p></li>
	</ul></div>
	<p>
	</p>
	<pre class="programlisting">
	static void
	maman_ibaz_base_init (gpointer g_class)
	{
	static gboolean is_initialized = FALSE;

	if (!is_initialized)
	{
	/* add properties and signals to the interface here */

	is_initialized = TRUE;
	}
	}

	GType
	maman_ibaz_get_type (void)
	{
	static GType iface_type = 0;
	if (iface_type == 0)
	{
	static const GTypeInfo info = {
	sizeof (MamanIbazInterface),
	maman_ibaz_base_init, /* base_init */
	NULL, /* base_finalize */
	};

	iface_type = g_type_register_static (G_TYPE_INTERFACE, "MamanIbaz",
	&info, 0);
	}

	return iface_type;
	}

	void
	maman_ibaz_do_action (MamanIbaz *self)
	{
	g_return_if_fail (MAMAN_IS_IBAZ (self));

	MAMAN_IBAZ_GET_INTERFACE (self)->do_action (self);
	}
	</pre>
	<p>
	</p>
	</div>
	</div>
	<div class="footer">
	<hr>
	Generated by GTK-Doc V1.14</div>
	</body>
	</html>