untracked/docs/reference/html/group__slot.html

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  22    <div id="projectname">libsigc++
  23    &#160;<span id="projectnumber">2.10.8</span>
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  44 <a href="#nested-classes">Classes</a>  </div>
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  46 <div class="title">Slots<div class="ingroups"><a class="el" href="group__sigcfunctors.html">Functors</a></div></div>  </div>
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  49
  50 <p>Slots are type-safe representations of callback methods and functions.
  51 <a href="#details">More...</a></p>
  52 <table class="memberdecls">
  53 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="nested-classes"></a>
  54 Classes</h2></td></tr>
  55 <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>
  56 <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>
  57 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  58 <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>
  59 <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>
  60 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  61 <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>
  62 <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>
  63 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  64 <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>
  65 <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>
  66 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  67 <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>
  68 <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>
  69 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  70 <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>
  71 <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>
  72 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  73 <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>
  74 <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>
  75 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  76 <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>
  77 <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>
  78 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  79 <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>
  80 <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>
  81 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  82 <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>
  83 <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>
  84 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  85 <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>
  86 <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>
  87 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  88 <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>
  89 <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>
  90 <tr class="separator:"><td class="memSeparator" colspan="2">&#160;</td></tr>
  91 </table>
  92 <a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
  93 <p>Slots are type-safe representations of callback methods and functions. </p>
  94 <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>
  95 <h1><a class="anchor" id="slots-creating"></a>
  96 Creating Slots</h1>
  97 <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>
  98 <div class="ttc" id="aclasssigc_1_1slot_html"><div class="ttname"><a href="classsigc_1_1slot.html">sigc::slot</a></div><div class="ttdoc">Convenience wrapper for the numbered sigc::slot# templates.</div><div class="ttdef"><b>Definition:</b> slot.h:1645</div></div>
  99 <div class="ttc" id="agroup__mem__fun_html_gadf6b6d22c503b439019f0a2e77352419"><div class="ttname"><a href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419">sigc::mem_fun</a></div><div class="ttdeci">mem_functor0&lt; T_return, T_obj &gt; mem_fun(T_return(T_obj::*_A_func)())</div><div class="ttdoc">Creates a functor of type sigc::mem_functor0 which wraps a method.</div><div class="ttdef"><b>Definition:</b> mem_fun.h:5797</div></div>
 100 </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>
 101 <div class="ttc" id="agroup__ptr__fun_html_ga9c80de72f656fb05e81fda622dddc863"><div class="ttname"><a href="group__ptr__fun.html#ga9c80de72f656fb05e81fda622dddc863">sigc::ptr_fun</a></div><div class="ttdeci">pointer_functor0&lt; T_return &gt; ptr_fun(T_return(*_A_func)())</div><div class="ttdoc">Creates a functor of type sigc::pointer_functor0 which wraps an existing non-member function.</div><div class="ttdef"><b>Definition:</b> ptr_fun.h:460</div></div>
 102 </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>
 103 </div><!-- fragment --><p>The compiler will complain if SomeClass::somemethod, etc. have the wrong signature.</p>
 104 <p>You can also pass slots as method parameters where you might normally pass a function pointer.</p>
 105 <h1><a class="anchor" id="slots-auto-disconnect"></a>
 106 Member Methods and Automatic Disconnection</h1>
 107 <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>
 108 <h1><a class="anchor" id="slots-auto"></a>
 109 auto</h1>
 110 <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>
 111 </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>
 112 </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>
 113 <h1><a class="anchor" id="slots-with-lambdas"></a>
 114 C++ Lambdas</h1>
 115 <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>
 116 <div class="line">  {</div>
 117 <div class="line">    someobj.somemethod(response_id);</div>
 118 <div class="line">    somefunction(response_id);</div>
 119 <div class="line">  };</div>
 120 <div class="line">m_Dialog.signal_response().connect(on_response);</div>
 121 </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>
 122 <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>
 123 <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>
 124 </ul>
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