libsigcplusplus/docs/reference/html/group__slot.html

119 lines
14 KiB
HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<meta name="generator" content="Doxygen 1.8.11"/>
<title>libsigc++: Slots</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<link href="doxygen.css" rel="stylesheet" type="text/css" />
<link href="doxygen-extra.css" rel="stylesheet" type="text/css"/>
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr style="height: 56px;">
<td id="projectalign" style="padding-left: 0.5em;">
<div id="projectname">libsigc++
&#160;<span id="projectnumber">2.10.3</span>
</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.8.11 -->
<div id="navrow1" class="tabs">
<ul class="tablist">
<li><a href="index.html"><span>Main&#160;Page</span></a></li>
<li><a href="pages.html"><span>Related&#160;Pages</span></a></li>
<li class="current"><a href="modules.html"><span>Modules</span></a></li>
<li><a href="namespaces.html"><span>Namespaces</span></a></li>
<li><a href="annotated.html"><span>Classes</span></a></li>
</ul>
</div>
</div><!-- top -->
<div class="header">
<div class="summary">
<a href="#nested-classes">Classes</a> </div>
<div class="headertitle">
<div class="title">Slots<div class="ingroups"><a class="el" href="group__sigcfunctors.html">Functors</a></div></div> </div>
</div><!--header-->
<div class="contents">
<p>Slots are type-safe representations of callback methods and functions.
<a href="#details">More...</a></p>
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="nested-classes"></a>
Classes</h2></td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">struct &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="structsigc_1_1nil.html">sigc::nil</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">nil struct type. <a href="structsigc_1_1nil.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot.html">sigc::slot&lt; T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Convenience wrapper for the numbered <a class="el" href="classsigc_1_1slot.html" title="Convenience wrapper for the numbered sigc::slot# templates. ">sigc::slot</a># templates. <a href="classsigc_1_1slot.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot0.html">sigc::slot0&lt; T_return &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot0.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot1.html">sigc::slot1&lt; T_return, T_arg1 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot1.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot2.html">sigc::slot2&lt; T_return, T_arg1, T_arg2 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot2.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot3.html">sigc::slot3&lt; T_return, T_arg1, T_arg2, T_arg3 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot3.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot4.html">sigc::slot4&lt; T_return, T_arg1, T_arg2, T_arg3, T_arg4 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot4.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot5.html">sigc::slot5&lt; T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot5.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot6.html">sigc::slot6&lt; T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot6.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot7.html">sigc::slot7&lt; T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7 &gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot7.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot_3_01T__return_07T__arg_8_8_8_08_4.html">sigc::slot&lt; T_return(T_arg...)&gt;</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Converts an arbitrary functor to a unified type which is opaque. <a href="classsigc_1_1slot_3_01T__return_07T__arg_8_8_8_08_4.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
<tr class="memitem:"><td class="memItemLeft" align="right" valign="top">class &#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1slot__base.html">sigc::slot_base</a></td></tr>
<tr class="memdesc:"><td class="mdescLeft">&#160;</td><td class="mdescRight">Base type for slots. <a href="classsigc_1_1slot__base.html#details">More...</a><br /></td></tr>
<tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
</table>
<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<p>Slots are type-safe representations of callback methods and functions. </p>
<p>A slot can be constructed from any function object or function, regardless of whether it is a global function, a member method, static, or virtual.</p>
<h1><a class="anchor" id="slots-creating"></a>
Creating Slots</h1>
<p>Use the <a class="el" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419" title="Creates a functor of type sigc::mem_functor0 which wraps a method. ">sigc::mem_fun()</a> or <a class="el" href="group__ptr__fun.html#ga9c80de72f656fb05e81fda622dddc863" title="Creates a functor of type sigc::pointer_functor0 which wraps an existing non-member function...">sigc::ptr_fun()</a> template functions to get a <a class="el" href="classsigc_1_1slot.html" title="Convenience wrapper for the numbered sigc::slot# templates. ">sigc::slot</a>, like so: </p><div class="fragment"><div class="line"><a class="code" href="classsigc_1_1slot.html">sigc::slot&lt;void, int&gt;</a> sl = <a class="code" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419">sigc::mem_fun</a>(someobj,&amp; SomeClass::somemethod);</div></div><!-- fragment --><p> or </p><div class="fragment"><div class="line"><a class="code" href="classsigc_1_1slot.html">sigc::slot&lt;void, int&gt;</a> sl = <a class="code" href="group__ptr__fun.html#ga9c80de72f656fb05e81fda622dddc863">sigc::ptr_fun</a>(&amp; somefunction);</div></div><!-- fragment --><p> or, in gtkmm, </p><div class="fragment"><div class="line">m_Button.signal_clicked().connect( <a class="code" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419">sigc::mem_fun</a>(*<span class="keyword">this</span>,&amp; MyWindow::on_button_clicked) );</div></div><!-- fragment --><p>The compiler will complain if SomeClass::somemethod, etc. have the wrong signature.</p>
<p>You can also pass slots as method parameters where you might normally pass a function pointer.</p>
<h1><a class="anchor" id="slots-auto-disconnect"></a>
Member Methods and Automatic Disconnection</h1>
<p>See <a class="el" href="group__mem__fun.html">sigc::mem_fun()</a> about deriving from <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection. ">sigc::trackable</a> to prevent member methods from being called after the instance has been destroyed.</p>
<h1><a class="anchor" id="slots-auto"></a>
auto</h1>
<p><a class="el" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419" title="Creates a functor of type sigc::mem_functor0 which wraps a method. ">sigc::mem_fun()</a> and <a class="el" href="group__ptr__fun.html#ga9c80de72f656fb05e81fda622dddc863" title="Creates a functor of type sigc::pointer_functor0 which wraps an existing non-member function...">sigc::ptr_fun()</a> return functors, but those functors are not slots. </p><div class="fragment"><div class="line"><a class="code" href="classsigc_1_1slot.html">sigc::slot&lt;void, int&gt;</a> sl = <a class="code" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419">sigc::mem_fun</a>(someobj,&amp; SomeClass::somemethod);</div></div><!-- fragment --><p> is not equivalent to </p><div class="fragment"><div class="line"><span class="keyword">auto</span> sl = <a class="code" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419">sigc::mem_fun</a>(someobj,&amp; SomeClass::somemethod); <span class="comment">// Not a slot!</span></div></div><!-- fragment --><p>If you don't explicitly use a <a class="el" href="classsigc_1_1slot.html" title="Convenience wrapper for the numbered sigc::slot# templates. ">sigc::slot</a> then the slot could call a method on an instance after it has been destroyed even if the method is in a class that derives from <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection. ">sigc::trackable</a>.</p>
<h1><a class="anchor" id="slots-with-lambdas"></a>
C++ Lambdas</h1>
<p>A C++11 lambda expression is a functor (function object). It is automatically wrapped in a slot, if it is connected to a signal. </p><div class="fragment"><div class="line"><span class="keyword">auto</span> on_response = [&amp;someobj] (<span class="keywordtype">int</span> response_id)</div><div class="line"> {</div><div class="line"> someobj.somemethod(response_id);</div><div class="line"> somefunction(response_id);</div><div class="line"> };</div><div class="line">m_Dialog.signal_response().connect(on_response);</div></div><!-- fragment --><p>If you connect a C++11 lambda expression or a std::function&lt;&gt; instance to a signal or assign it to a slot,</p><ul>
<li>With libsigc++ versions before 2.6, if the return type is not void, you must use the <a class="el" href="group__sigcfunctors.html#gadf1ba3cacb09cc5c3c3e399836ec6e50" title="Helper macro, if you want to mix user-defined and third party functors with libsigc++. ">SIGC_FUNCTORS_DEDUCE_RESULT_TYPE_WITH_DECLTYPE</a> macro,</li>
<li>if your functor contains references to <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection. ">sigc::trackable</a> derived objects, those objects will not be tracked, unless you also use <a class="el" href="group__track__obj.html#ga8fd1ab36d123ff83dd4cd8dc58bb28e2" title="Creates an adaptor of type sigc::track_obj_functor1 which wraps a functor. ">sigc::track_obj()</a>. </li>
</ul>
</div><!-- contents -->
<!-- start footer part -->
<hr class="footer"/><address class="footer"><small>
Generated on Wed Mar 25 2020 10:13:27 for libsigc++ by &#160;<a href="http://www.doxygen.org/index.html">
<img class="footer" src="doxygen.png" alt="doxygen"/>
</a> 1.8.11
</small></address>
</body>
</html>