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<div class="navpath"><a class="el" href="namespaceGlib.html">Glib</a>::<a class="el" href="classGlib_1_1Dispatcher.html">Dispatcher</a>
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<h1>Glib::Dispatcher Class Reference<br/>
<small>
[<a class="el" href="group__Threads.html">Threads</a>]</small>
</h1><!-- doxytag: class="Glib::Dispatcher" -->
<p>Signal class for inter-thread communication. <a href="#_details">More...</a></p>
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Collaboration diagram for Glib::Dispatcher:</div>
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<area shape="rect" href="../../../libsigc++-2.0/reference/html/classsigc_1_1signal.html" title="sigc::signal\< void \>" alt="" coords="2515,56,2651,85"/><area shape="rect" href="../../../libsigc++-2.0/reference/html/structsigc_1_1signal__base.html" title="sigc::signal_base" alt="" coords="163,61,285,91"/><area shape="rect" href="../../../libsigc++-2.0/reference/html/classsigc_1_1signal7.html" title="signal7\< T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7, T_accumulator \>" alt="" coords="337,61,900,91"/><area shape="rect" href="../../../libsigc++-2.0/reference/html/structsigc_1_1trackable.html" title="sigc::trackable" alt="" coords="5,61,112,91"/><area shape="rect" href="../../../libsigc++-2.0/reference/html/classsigc_1_1signal.html" title="sigc::signal\< T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7 \>" alt="" coords="1923,85,2419,115"/></map>
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<p><a href="classGlib_1_1Dispatcher-members.html">List of all members.</a></p>
<table border="0" cellpadding="0" cellspacing="0">
<tr><td colspan="2"><h2>Public Member Functions</h2></td></tr>
<tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classGlib_1_1Dispatcher.html#a1883255c63f36e1d218ccf3f1abfa992">Dispatcher</a> ()</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Create new <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> instance using the default main context. <a href="#a1883255c63f36e1d218ccf3f1abfa992"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classGlib_1_1Dispatcher.html#a14692fe3e39140fc164cbd03149a7ce1">Dispatcher</a> (const <a class="el" href="classGlib_1_1RefPtr.html">Glib::RefPtr</a>< <a class="el" href="classGlib_1_1MainContext.html">MainContext</a> >& context)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Create new <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> instance using an arbitrary main context. <a href="#a14692fe3e39140fc164cbd03149a7ce1"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="classGlib_1_1Dispatcher.html#a6d220afa9063f8cf1364d5a1c73eb010">~Dispatcher</a> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classGlib_1_1Dispatcher.html#a07b89c90f931db118c8c184d0615ce92">emit</a> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="classGlib_1_1Dispatcher.html#a4610275deedf1324bf71afde1c8c71ea">operator()</a> ()</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">sigc::connection </td><td class="memItemRight" valign="bottom"><a class="el" href="classGlib_1_1Dispatcher.html#a63645395ac79c03b5ec9e81d8099dea7">connect</a> (const sigc::slot< void >&<a class="elRef" href="../../../libsigc++-2.0/reference/html/classsigc_1_1slot.html">slot</a>)</td></tr>
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<hr/><a name="_details"></a><h2>Detailed Description</h2>
<p>Signal class for inter-thread communication. </p>
<p><a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Glib::Dispatcher</a> works similar to sigc::signal<void>. But unlike normal signals, the notification happens asynchronously through a pipe. This is a simple and efficient way of communicating between threads, and especially useful in a thread model with a single GUI thread.</p>
<p>No mutex locking is involved, apart from the operating system's internal I/O locking. That implies some usage rules:</p>
<ul>
<li>Only one thread may connect to the signal and receive notification, but multiple senders are allowed even without locking. </li>
<li>The GLib main loop must run in the receiving thread (this will be the GUI thread usually). </li>
<li>The <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> object must be instantiated by the receiver thread. </li>
<li>The <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> object should be instantiated before creating any of the sender threads, if you want to avoid extra locking.</li>
</ul>
<p>Notes about performance:</p>
<ul>
<li>After instantiation, <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Glib::Dispatcher</a> will never lock any mutexes on its own. The interaction with the GLib main loop might involve locking on the <em>receiver</em> side. The <em>sender</em> side, however, is guaranteed not to lock, except for internal locking in the <code>write()</code> system call. </li>
<li>All <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> instances of a receiver thread share the same pipe. That is, if you use <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Glib::Dispatcher</a> only to notify the GUI thread, only one pipe is created no matter how many <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> objects you have.</li>
</ul>
<p>Using <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Glib::Dispatcher</a> on Windows:</p>
<p><a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Glib::Dispatcher</a> also works on win32-based systems. Unfortunately though, the implementation cannot use a pipe on win32 and therefore does have to lock a mutex on emission, too. However, the impact on performance is likely minor and the notification still happens asynchronously. Apart from the additional lock the behavior matches the Unix implementation. </p>
<dl><dt><b>Examples: </b></dt><dd>
<p><a class="el" href="thread_2dispatcher_8cc-example.html#_a2">thread/dispatcher.cc</a>.</p>
</dd>
</dl><hr/><h2>Constructor & Destructor Documentation</h2>
<a class="anchor" id="a1883255c63f36e1d218ccf3f1abfa992"></a><!-- doxytag: member="Glib::Dispatcher::Dispatcher" ref="a1883255c63f36e1d218ccf3f1abfa992" args="()" -->
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<td class="memname">Glib::Dispatcher::Dispatcher </td>
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<p>Create new <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> instance using the default main context. </p>
<dl><dt><b>Exceptions:</b></dt><dd>
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<tr><td valign="top"></td><td valign="top"><em><a class="el" href="classGlib_1_1FileError.html" title="Exception class for file-related errors.">Glib::FileError</a></em> </td><td></td></tr>
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<a class="anchor" id="a14692fe3e39140fc164cbd03149a7ce1"></a><!-- doxytag: member="Glib::Dispatcher::Dispatcher" ref="a14692fe3e39140fc164cbd03149a7ce1" args="(const Glib::RefPtr< MainContext > &context)" -->
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<td class="memname">Glib::Dispatcher::Dispatcher </td>
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<td class="paramtype">const <a class="el" href="classGlib_1_1RefPtr.html">Glib::RefPtr</a>< <a class="el" href="classGlib_1_1MainContext.html">MainContext</a> >& </td>
<td class="paramname"> <em>context</em></td>
<td> ) </td>
<td><code> [explicit]</code></td>
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<p>Create new <a class="el" href="classGlib_1_1Dispatcher.html" title="Signal class for inter-thread communication.">Dispatcher</a> instance using an arbitrary main context. </p>
<dl><dt><b>Exceptions:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em><a class="el" href="classGlib_1_1FileError.html" title="Exception class for file-related errors.">Glib::FileError</a></em> </td><td></td></tr>
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<a class="anchor" id="a6d220afa9063f8cf1364d5a1c73eb010"></a><!-- doxytag: member="Glib::Dispatcher::~Dispatcher" ref="a6d220afa9063f8cf1364d5a1c73eb010" args="()" -->
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<td class="memname">Glib::Dispatcher::~Dispatcher </td>
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<hr/><h2>Member Function Documentation</h2>
<a class="anchor" id="a63645395ac79c03b5ec9e81d8099dea7"></a><!-- doxytag: member="Glib::Dispatcher::connect" ref="a63645395ac79c03b5ec9e81d8099dea7" args="(const sigc::slot< void > &slot)" -->
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<td class="memname">sigc::connection Glib::Dispatcher::connect </td>
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<td class="paramtype">const sigc::slot< void > & </td>
<td class="paramname"> <em>slot</em></td>
<td> ) </td>
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<a class="anchor" id="a07b89c90f931db118c8c184d0615ce92"></a><!-- doxytag: member="Glib::Dispatcher::emit" ref="a07b89c90f931db118c8c184d0615ce92" args="()" -->
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<td class="memname">void Glib::Dispatcher::emit </td>
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<a class="anchor" id="a4610275deedf1324bf71afde1c8c71ea"></a><!-- doxytag: member="Glib::Dispatcher::operator()" ref="a4610275deedf1324bf71afde1c8c71ea" args="()" -->
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<td class="memname">void Glib::Dispatcher::operator() </td>
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<hr/>The documentation for this class was generated from the following file:<ul>
<li>glibmm/dispatcher.h</li>
</ul>
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