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| author | Leo Tenenbaum <pommicket@gmail.com> | 2018-08-20 21:12:06 -0400 |
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| committer | Leo Tenenbaum <pommicket@gmail.com> | 2018-08-20 21:12:06 -0400 |
| commit | 63e87c2d0c9d263f14c77b68f85c67d46ece82a9 (patch) | |
| tree | 6260365cbf7d24f37d27669e8538227fcb72e243 /gtk+-mingw/share/gtk-doc/html/gobject/howto-gobject-methods.html | |
| parent | a4460f6d9453bbd7e584937686449cef3e19f052 (diff) | |
Diffstat (limited to 'gtk+-mingw/share/gtk-doc/html/gobject/howto-gobject-methods.html')
| -rw-r--r-- | gtk+-mingw/share/gtk-doc/html/gobject/howto-gobject-methods.html | 257 |
1 files changed, 0 insertions, 257 deletions
diff --git a/gtk+-mingw/share/gtk-doc/html/gobject/howto-gobject-methods.html b/gtk+-mingw/share/gtk-doc/html/gobject/howto-gobject-methods.html deleted file mode 100644 index 299fc63..0000000 --- a/gtk+-mingw/share/gtk-doc/html/gobject/howto-gobject-methods.html +++ /dev/null @@ -1,257 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> -<title>Object methods</title> -<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> -<link rel="home" href="index.html" title="GObject Reference Manual"> -<link rel="up" href="howto-gobject.html" title="How to define and implement a new GObject"> -<link rel="prev" href="howto-gobject-destruction.html" title="Object Destruction"> -<link rel="next" href="howto-gobject-chainup.html" title="Chaining up"> -<meta name="generator" content="GTK-Doc V1.18 (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-destruction.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td> -<td><a accesskey="u" href="howto-gobject.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-gobject-chainup.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td> -</tr></table> -<div class="sect1"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="howto-gobject-methods"></a>Object methods</h2></div></div></div> -<p> - Just as with C++, there are many different ways to define object - methods and extend them: the following list and sections draw on - C++ vocabulary. (Readers are expected to know basic C++ buzzwords. - Those who have not had to write C++ code recently can refer to e.g. - <a class="ulink" href="http://www.cplusplus.com/doc/tutorial/" target="_top">http://www.cplusplus.com/doc/tutorial/</a> to refresh - their memories.) - </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"> -<li class="listitem"><p> - non-virtual public methods, - </p></li> -<li class="listitem"><p> - virtual public methods and - </p></li> -<li class="listitem"><p> - virtual private methods - </p></li> -</ul></div> -<p> - </p> -<div class="sect2"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="idp21629936"></a>Non-virtual public methods</h3></div></div></div> -<p> - These are the simplest: you want to provide a simple method which - can act on your object. All you need to do is to provide a function - prototype in the header and an implementation of that prototype - in the source file. -</p> -<pre class="programlisting"> -/* declaration in the header. */ -void maman_bar_do_action (MamanBar *self, /* parameters */); - -/* implementation in the source file */ -void -maman_bar_do_action (MamanBar *self, /* parameters */) -{ - g_return_if_fail (MAMAN_IS_BAR (self)); - - /* do stuff here. */ -} -</pre> -<p> - </p> -<p>There is really nothing scary about this.</p> -</div> -<div class="sect2"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="idp21632928"></a>Virtual public methods</h3></div></div></div> -<p> - This is the preferred way to create polymorphic GObjects. All you - need to do is to define the common method and its class function in - the public header, implement the common method in the source file - and re-implement the class function in each object which inherits - from you. -</p> -<pre class="programlisting"> -/* declaration in maman-bar.h. */ -struct _MamanBarClass -{ - GObjectClass parent_class; - - /* stuff */ - void (*do_action) (MamanBar *self, /* parameters */); -}; - -void maman_bar_do_action (MamanBar *self, /* parameters */); - -/* implementation in maman-bar.c */ -void -maman_bar_do_action (MamanBar *self, /* parameters */) -{ - g_return_if_fail (MAMAN_IS_BAR (self)); - - MAMAN_BAR_GET_CLASS (self)->do_action (self, /* parameters */); -} -</pre> -<p> - The code above simply redirects the do_action call to the relevant - class function. Some users, concerned about performance, do not - provide the <code class="function">maman_bar_do_action</code> wrapper function - and require users to dereference the class pointer themselves. This - is not such a great idea in terms of encapsulation and makes it - difficult to change the object's implementation afterwards, should - this be needed. - </p> -<p> - Other users, also concerned by performance issues, declare - the <code class="function">maman_bar_do_action</code> function inline in the - header file. This, however, makes it difficult to change the - object's implementation later (although easier than requiring users - to directly dereference the class function) and is often difficult - to write in a portable way (the <span class="emphasis"><em>inline</em></span> keyword - is part of the C99 standard but not every compiler supports it). - </p> -<p> - In doubt, unless a user shows you hard numbers about the performance - cost of the function call, just implement <code class="function">maman_bar_do_action</code> - in the source file. - </p> -<p> - Please, note that it is possible for you to provide a default - implementation for this class method in the object's - <code class="function">class_init</code> function: initialize the - klass->do_action field to a pointer to the actual implementation. - You can also make this class method pure virtual by initializing - the klass->do_action field to NULL: -</p> -<pre class="programlisting"> -static void -maman_bar_real_do_action_two (MamanBar *self, /* parameters */) -{ - /* Default implementation for the virtual method. */ -} - -static void -maman_bar_class_init (BarClass *klass) -{ - /* pure virtual method: mandates implementation in children. */ - klass->do_action_one = NULL; - - /* merely virtual method. */ - klass->do_action_two = maman_bar_real_do_action_two; -} - -void -maman_bar_do_action_one (MamanBar *self, /* parameters */) -{ - g_return_if_fail (MAMAN_IS_BAR (self)); - - MAMAN_BAR_GET_CLASS (self)->do_action_one (self, /* parameters */); -} - -void -maman_bar_do_action_two (MamanBar *self, /* parameters */) -{ - g_return_if_fail (MAMAN_IS_BAR (self)); - - MAMAN_BAR_GET_CLASS (self)->do_action_two (self, /* parameters */); -} -</pre> -<p> - </p> -</div> -<div class="sect2"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="idp21643024"></a>Virtual private Methods</h3></div></div></div> -<p> - These are very similar to Virtual Public methods. They just don't - have a public function to call the function directly. The header - file contains only a declaration of the class function: -</p> -<pre class="programlisting"> -/* declaration in maman-bar.h. */ -struct _MamanBarClass -{ - GObjectClass parent; - - /* stuff */ - void (* helper_do_specific_action) (MamanBar *self, /* parameters */); -}; - -void maman_bar_do_any_action (MamanBar *self, /* parameters */); -</pre> -<p> - These class functions are often used to delegate part of the job - to child classes: -</p> -<pre class="programlisting"> -/* this accessor function is static: it is not exported outside of this file. */ -static void -maman_bar_do_specific_action (MamanBar *self, /* parameters */) -{ - MAMAN_BAR_GET_CLASS (self)->do_specific_action (self, /* parameters */); -} - -void -maman_bar_do_any_action (MamanBar *self, /* parameters */) -{ - /* random code here */ - - /* - * Try to execute the requested action. Maybe the requested action - * cannot be implemented here. So, we delegate its implementation - * to the child class: - */ - maman_bar_do_specific_action (self, /* parameters */); - - /* other random code here */ -} -</pre> -<p> - </p> -<p> - Again, it is possible to provide a default implementation for this - private virtual class function: -</p> -<pre class="programlisting"> -static void -maman_bar_class_init (MamanBarClass *klass) -{ - /* pure virtual method: mandates implementation in children. */ - klass->do_specific_action_one = NULL; - - /* merely virtual method. */ - klass->do_specific_action_two = maman_bar_real_do_specific_action_two; -} -</pre> -<p> - </p> -<p> - Children can then implement the subclass with code such as: -</p> -<pre class="programlisting"> -static void -maman_bar_subtype_class_init (MamanBarSubTypeClass *klass) -{ - MamanBarClass *bar_class = MAMAN_BAR_CLASS (klass); - - /* implement pure virtual class function. */ - bar_class->do_specific_action_one = maman_bar_subtype_do_specific_action_one; -} -</pre> -<p> - </p> -</div> -</div> -<div class="footer"> -<hr> - Generated by GTK-Doc V1.18</div> -</body> -</html>
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