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| author | Leo Tenenbaum <pommicket@gmail.com> | 2018-08-20 21:12:06 -0400 |
|---|---|---|
| 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/chapter-signal.html | |
| parent | a4460f6d9453bbd7e584937686449cef3e19f052 (diff) | |
Diffstat (limited to 'gtk+-mingw/share/gtk-doc/html/gobject/chapter-signal.html')
| -rw-r--r-- | gtk+-mingw/share/gtk-doc/html/gobject/chapter-signal.html | 214 |
1 files changed, 0 insertions, 214 deletions
diff --git a/gtk+-mingw/share/gtk-doc/html/gobject/chapter-signal.html b/gtk+-mingw/share/gtk-doc/html/gobject/chapter-signal.html deleted file mode 100644 index 71ffa37..0000000 --- a/gtk+-mingw/share/gtk-doc/html/gobject/chapter-signal.html +++ /dev/null @@ -1,214 +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>The GObject messaging system</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="pt01.html" title="Part I. Concepts"> -<link rel="prev" href="gobject-properties.html" title="Object properties"> -<link rel="next" href="signal.html" title="Signals"> -<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="gobject-properties.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td> -<td><a accesskey="u" href="pt01.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="signal.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td> -</tr></table> -<div class="chapter"> -<div class="titlepage"><div><div><h2 class="title"> -<a name="chapter-signal"></a>The GObject messaging system</h2></div></div></div> -<div class="toc"><dl> -<dt><span class="sect1"><a href="chapter-signal.html#closure">Closures</a></span></dt> -<dd><dl> -<dt><span class="sect2"><a href="chapter-signal.html#idp9473520">C Closures</a></span></dt> -<dt><span class="sect2"><a href="chapter-signal.html#idp6382272">Non-C closures (for the fearless)</a></span></dt> -</dl></dd> -<dt><span class="sect1"><a href="signal.html">Signals</a></span></dt> -<dd><dl> -<dt><span class="sect2"><a href="signal.html#signal-registration">Signal registration</a></span></dt> -<dt><span class="sect2"><a href="signal.html#signal-connection">Signal connection</a></span></dt> -<dt><span class="sect2"><a href="signal.html#signal-emission">Signal emission</a></span></dt> -<dt><span class="sect2"><a href="signal.html#signal-detail">The <span class="emphasis"><em>detail</em></span> argument</a></span></dt> -</dl></dd> -</dl></div> -<div class="sect1"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="closure"></a>Closures</h2></div></div></div> -<p> - Closures are central to the concept of asynchronous signal delivery - which is widely used throughout GTK+ and GNOME applications. A closure is an - abstraction, a generic representation of a callback. It is a small structure - which contains three objects: - </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"> -<li class="listitem"> -<p>a function pointer (the callback itself) whose prototype looks like: -</p> -<pre class="programlisting"> -return_type function_callback (... , gpointer user_data); -</pre> -<p> - </p> -</li> -<li class="listitem"><p> - the user_data pointer which is passed to the callback upon invocation of the closure - </p></li> -<li class="listitem"><p> - a function pointer which represents the destructor of the closure: whenever the - closure's refcount reaches zero, this function will be called before the closure - structure is freed. - </p></li> -</ul></div> -<p> - </p> -<p> - The <a class="link" href="gobject-Closures.html#GClosure" title="struct GClosure"><span class="type">GClosure</span></a> structure represents the common functionality of all - closure implementations: there exists a different Closure implementation for - each separate runtime which wants to use the GObject type system. - <sup>[<a name="idp8360640" href="#ftn.idp8360640" class="footnote">6</a>]</sup> - The GObject library provides a simple <a class="link" href="gobject-Closures.html#GCClosure" title="struct GCClosure"><span class="type">GCClosure</span></a> type which - is a specific implementation of closures to be used with C/C++ callbacks. - </p> -<p> - A <a class="link" href="gobject-Closures.html#GClosure" title="struct GClosure"><span class="type">GClosure</span></a> provides simple services: - </p> -<div class="itemizedlist"><ul class="itemizedlist" type="disc"> -<li class="listitem"><p> - Invocation (<code class="function"><a class="link" href="gobject-Closures.html#g-closure-invoke" title="g_closure_invoke ()">g_closure_invoke</a></code>): this is what closures - were created for: they hide the details of callback invocation from the - callback invoker.</p></li> -<li class="listitem"><p> - Notification: the closure notifies listeners of certain events such as - closure invocation, closure invalidation and closure finalization. Listeners - can be registered with <code class="function"><a class="link" href="gobject-Closures.html#g-closure-add-finalize-notifier" title="g_closure_add_finalize_notifier ()">g_closure_add_finalize_notifier</a></code> - (finalization notification), <code class="function"><a class="link" href="gobject-Closures.html#g-closure-add-invalidate-notifier" title="g_closure_add_invalidate_notifier ()">g_closure_add_invalidate_notifier</a></code> - (invalidation notification) and - <code class="function"><a class="link" href="gobject-Closures.html#g-closure-add-marshal-guards" title="g_closure_add_marshal_guards ()">g_closure_add_marshal_guards</a></code> (invocation notification). - There exist symmetric deregistration functions for finalization and invalidation - events (<code class="function"><a class="link" href="gobject-Closures.html#g-closure-remove-finalize-notifier" title="g_closure_remove_finalize_notifier ()">g_closure_remove_finalize_notifier</a></code> and - <code class="function"><a class="link" href="gobject-Closures.html#g-closure-remove-invalidate-notifier" title="g_closure_remove_invalidate_notifier ()">g_closure_remove_invalidate_notifier</a></code>) but not for the invocation - process. - <sup>[<a name="idp7220656" href="#ftn.idp7220656" class="footnote">7</a>]</sup></p></li> -</ul></div> -<p> - </p> -<div class="sect2"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="idp9473520"></a>C Closures</h3></div></div></div> -<p> - If you are using C or C++ - to connect a callback to a given event, you will either use simple <a class="link" href="gobject-Closures.html#GCClosure" title="struct GCClosure"><span class="type">GCClosure</span></a>s - which have a pretty minimal API or the even simpler <code class="function"><a class="link" href="gobject-Signals.html#g-signal-connect" title="g_signal_connect()">g_signal_connect</a></code> - functions (which will be presented a bit later :). -</p> -<pre class="programlisting"> -GClosure *g_cclosure_new (GCallback callback_func, - gpointer user_data, - GClosureNotify destroy_data); -GClosure *g_cclosure_new_swap (GCallback callback_func, - gpointer user_data, - GClosureNotify destroy_data); -GClosure *g_signal_type_cclosure_new (GType itype, - guint struct_offset); -</pre> -<p> - </p> -<p> - <code class="function"><a class="link" href="gobject-Closures.html#g-cclosure-new" title="g_cclosure_new ()">g_cclosure_new</a></code> will create a new closure which can invoke the - user-provided callback_func with the user-provided user_data as last parameter. When the closure - is finalized (second stage of the destruction process), it will invoke the destroy_data function - if the user has supplied one. - </p> -<p> - <code class="function"><a class="link" href="gobject-Closures.html#g-cclosure-new-swap" title="g_cclosure_new_swap ()">g_cclosure_new_swap</a></code> will create a new closure which can invoke the - user-provided callback_func with the user-provided user_data as first parameter (instead of being the - last parameter as with <code class="function"><a class="link" href="gobject-Closures.html#g-cclosure-new" title="g_cclosure_new ()">g_cclosure_new</a></code>). When the closure - is finalized (second stage of the destruction process), it will invoke the destroy_data - function if the user has supplied one. - </p> -</div> -<div class="sect2"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="idp6382272"></a>Non-C closures (for the fearless)</h3></div></div></div> -<p> - As was explained above, closures hide the details of callback invocation. In C, - callback invocation is just like function invocation: it is a matter of creating - the correct stack frame for the called function and executing a <span class="emphasis"><em>call</em></span> - assembly instruction. - </p> -<p> - C closure marshallers transform the array of GValues which represent - the parameters to the target function into a C-style function parameter list, invoke - the user-supplied C function with this new parameter list, get the return value of the - function, transform it into a GValue and return this GValue to the marshaller caller. - </p> -<p> - The following code implements a simple marshaller in C for a C function which takes an - integer as first parameter and returns void. -</p> -<pre class="programlisting"> -g_cclosure_marshal_VOID__INT (GClosure *closure, - GValue *return_value, - guint n_param_values, - const GValue *param_values, - gpointer invocation_hint, - gpointer marshal_data) -{ - typedef void (*GMarshalFunc_VOID__INT) (gpointer data1, - gint arg_1, - gpointer data2); - register GMarshalFunc_VOID__INT callback; - register GCClosure *cc = (GCClosure*) closure; - register gpointer data1, data2; - - g_return_if_fail (n_param_values == 2); - - data1 = g_value_peek_pointer (param_values + 0); - data2 = closure->data; - - callback = (GMarshalFunc_VOID__INT) (marshal_data ? marshal_data : cc->callback); - - callback (data1, - g_marshal_value_peek_int (param_values + 1), - data2); -} -</pre> -<p> - </p> -<p> - Of course, there exist other kinds of marshallers. For example, James Henstridge - wrote a generic Python marshaller which is used by all Python closures (a Python closure - is used to have Python-based callback be invoked by the closure invocation process). - This Python marshaller transforms the input GValue list representing the function - parameters into a Python tuple which is the equivalent structure in Python (you can - look in <code class="function">pyg_closure_marshal</code> in <code class="filename">pygtype.c</code> - in the <span class="emphasis"><em>pygobject</em></span> module in the GNOME source code repository). - </p> -</div> -</div> -<div class="footnotes"> -<br><hr width="100" align="left"> -<div class="footnote"><p><sup>[<a id="ftn.idp8360640" href="#idp8360640" class="para">6</a>] </sup> - In practice, closures sit at the boundary of language runtimes: if you are - writing Python code and one of your Python callbacks receives a signal from - a GTK+ widget, the C code in GTK+ needs to execute your Python - code. The closure invoked by the GTK+ object invokes the Python callback: - it behaves as a normal C object for GTK+ and as a normal Python object for - Python code. - </p></div> -<div class="footnote"><p><sup>[<a id="ftn.idp7220656" href="#idp7220656" class="para">7</a>] </sup> - Closures are reference counted and notify listeners of their destruction in a two-stage - process: the invalidation notifiers are invoked before the finalization notifiers. - </p></div> -</div> -</div> -<div class="footer"> -<hr> - Generated by GTK-Doc V1.18</div> -</body> -</html>
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