untracked/docs/reference/html/classsigc_1_1volatile__limit__reference.html

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   8 <title>libsigc++: sigc::volatile_limit_reference&lt; T_type, I_derives_trackable &gt; Class Template Reference</title>
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  44 </div>
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  46 <div class="header">
  47   <div class="summary">
  48 <a href="#pub-methods">Public Member Functions</a> &#124;
  49 <a href="classsigc_1_1volatile__limit__reference-members.html">List of all members</a>  </div>
  50   <div class="headertitle">
  51 <div class="title">sigc::volatile_limit_reference&lt; T_type, I_derives_trackable &gt; Class Template Reference</div>  </div>
  52 </div><!--header-->
  53 <div class="contents">
  54
  55 <p>A volatile_limit_reference&lt;Foo&gt; object stores a reference (Foo&amp;), but make sure that, if Foo inherits from <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a>, then <a class="el" href="group__sigcfunctors.html#ga64cb7832acc1e58efb5ffe0b4f5e9404" title="This function performs a functor on each of the targets of a functor.">visit_each&lt;&gt;()</a> will "limit" itself to the <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a> reference instead of the derived reference.
  56  <a href="classsigc_1_1volatile__limit__reference.html#details">More...</a></p>
  57
  58 <p><code>#include &lt;sigc++/limit_reference.h&gt;</code></p>
  59 <table class="memberdecls">
  60 <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="pub-methods"></a>
  61 Public Member Functions</h2></td></tr>
  62 <tr class="memitem:acb3e6e1ecc628343f94faae718b58066"><td class="memItemLeft" align="right" valign="top">&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1volatile__limit__reference.html#acb3e6e1ecc628343f94faae718b58066">volatile_limit_reference</a> (T_type &amp; _A_target)</td></tr>
  63 <tr class="memdesc:acb3e6e1ecc628343f94faae718b58066"><td class="mdescLeft">&#160;</td><td class="mdescRight">Constructor.  <a href="classsigc_1_1volatile__limit__reference.html#acb3e6e1ecc628343f94faae718b58066">More...</a><br /></td></tr>
  64 <tr class="separator:acb3e6e1ecc628343f94faae718b58066"><td class="memSeparator" colspan="2">&#160;</td></tr>
  65 <tr class="memitem:a0157cc89d9db4032c7a8f9159ebaeff3"><td class="memItemLeft" align="right" valign="top">volatile T_type &amp;&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1volatile__limit__reference.html#a0157cc89d9db4032c7a8f9159ebaeff3">invoke</a> () const</td></tr>
  66 <tr class="memdesc:a0157cc89d9db4032c7a8f9159ebaeff3"><td class="mdescLeft">&#160;</td><td class="mdescRight">Retrieve the reference.  <a href="classsigc_1_1volatile__limit__reference.html#a0157cc89d9db4032c7a8f9159ebaeff3">More...</a><br /></td></tr>
  67 <tr class="separator:a0157cc89d9db4032c7a8f9159ebaeff3"><td class="memSeparator" colspan="2">&#160;</td></tr>
  68 <tr class="memitem:a4d67fe2d9d27c326136a9e5ac13a1a75"><td class="memItemLeft" align="right" valign="top">const T_type &amp;&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="classsigc_1_1volatile__limit__reference.html#a4d67fe2d9d27c326136a9e5ac13a1a75">visit</a> () const</td></tr>
  69 <tr class="memdesc:a4d67fe2d9d27c326136a9e5ac13a1a75"><td class="mdescLeft">&#160;</td><td class="mdescRight">Retrieve the entity to visit for <a class="el" href="group__sigcfunctors.html#ga64cb7832acc1e58efb5ffe0b4f5e9404" title="This function performs a functor on each of the targets of a functor.">visit_each()</a>.  <a href="classsigc_1_1volatile__limit__reference.html#a4d67fe2d9d27c326136a9e5ac13a1a75">More...</a><br /></td></tr>
  70 <tr class="separator:a4d67fe2d9d27c326136a9e5ac13a1a75"><td class="memSeparator" colspan="2">&#160;</td></tr>
  71 </table>
  72 <a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
  73 <div class="textblock"><h3>template&lt;class T_type, bool I_derives_trackable = std::is_base_of&lt;trackable, T_type&gt;::value&gt;<br />
  74 class sigc::volatile_limit_reference&lt; T_type, I_derives_trackable &gt;</h3>
  75
  76 <p>A volatile_limit_reference&lt;Foo&gt; object stores a reference (Foo&amp;), but make sure that, if Foo inherits from <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a>, then <a class="el" href="group__sigcfunctors.html#ga64cb7832acc1e58efb5ffe0b4f5e9404" title="This function performs a functor on each of the targets of a functor.">visit_each&lt;&gt;()</a> will "limit" itself to the <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a> reference instead of the derived reference. </p>
  77 <p>This avoids use of a reference to the derived type when the derived destructor has run. That can be a problem when using virtual inheritance.</p>
  78 <p>If Foo inherits from trackable then both the derived reference and the <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a> reference are stored, so we can later retrieve the <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a> reference without doing an implicit conversion. To retrieve the derived reference (so that you invoke methods or members of it), use <a class="el" href="classsigc_1_1volatile__limit__reference.html#a0157cc89d9db4032c7a8f9159ebaeff3" title="Retrieve the reference.">invoke()</a>. To retrieve the trackable reference (so that you can call <a class="el" href="group__sigcfunctors.html#ga64cb7832acc1e58efb5ffe0b4f5e9404" title="This function performs a functor on each of the targets of a functor.">visit_each()</a> on it), you use <a class="el" href="classsigc_1_1volatile__limit__reference.html#a4d67fe2d9d27c326136a9e5ac13a1a75" title="Retrieve the entity to visit for visit_each().">visit()</a>.</p>
  79 <p>If Foo does not inherit from <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a> then <a class="el" href="classsigc_1_1volatile__limit__reference.html#a0157cc89d9db4032c7a8f9159ebaeff3" title="Retrieve the reference.">invoke()</a> and <a class="el" href="classsigc_1_1volatile__limit__reference.html#a4d67fe2d9d27c326136a9e5ac13a1a75" title="Retrieve the entity to visit for visit_each().">visit()</a> just return the derived reference.</p>
  80 <p>This is used for bound (<a class="el" href="group__bind.html#ga2f099bc6056b32f2a58134ba8537c6f4" title="Creates an adaptor of type sigc::bind_functor which binds the passed argument to the passed functor.">sigc::bind</a>) slot parameters (via <a class="el" href="classsigc_1_1bound__argument.html" title="A bound_argument&lt;Foo&gt; object stores a bound (for instance, with sigc::bind(), or sigc::bind_return())...">bound_argument</a>), bound return values, and, with <a class="el" href="group__mem__fun.html#gadf6b6d22c503b439019f0a2e77352419" title="Creates a functor of type sigc::mem_functor0 which wraps a method.">mem_fun()</a>, the reference to the handling object.</p>
  81 <ul>
  82 <li><em>T_type</em> The type of the reference. </li>
  83 </ul>
  84 </div><h2 class="groupheader">Constructor &amp; Destructor Documentation</h2>
  85 <a id="acb3e6e1ecc628343f94faae718b58066"></a>
  86 <h2 class="memtitle"><span class="permalink"><a href="#acb3e6e1ecc628343f94faae718b58066">&#9670;&#160;</a></span>volatile_limit_reference()</h2>
  87
  88 <div class="memitem">
  89 <div class="memproto">
  90 <div class="memtemplate">
  91 template &lt;class T_type , bool I_derives_trackable = std::is_base_of&lt;trackable, T_type&gt;::value&gt; </div>
  92 <table class="mlabels">
  93   <tr>
  94   <td class="mlabels-left">
  95       <table class="memname">
  96         <tr>
  97           <td class="memname"><a class="el" href="classsigc_1_1volatile__limit__reference.html">sigc::volatile_limit_reference</a>&lt; T_type, I_derives_trackable &gt;::<a class="el" href="classsigc_1_1volatile__limit__reference.html">volatile_limit_reference</a> </td>
  98           <td>(</td>
  99           <td class="paramtype">T_type &amp;&#160;</td>
 100           <td class="paramname"><em>_A_target</em></td><td>)</td>
 101           <td></td>
 102         </tr>
 103       </table>
 104   </td>
 105   <td class="mlabels-right">
 106 <span class="mlabels"><span class="mlabel">inline</span></span>  </td>
 107   </tr>
 108 </table>
 109 </div><div class="memdoc">
 110
 111 <p>Constructor. </p>
 112 <dl class="params"><dt>Parameters</dt><dd>
 113   <table class="params">
 114     <tr><td class="paramname">_A_target</td><td>The reference to limit. </td></tr>
 115   </table>
 116   </dd>
 117 </dl>
 118
 119 </div>
 120 </div>
 121 <h2 class="groupheader">Member Function Documentation</h2>
 122 <a id="a0157cc89d9db4032c7a8f9159ebaeff3"></a>
 123 <h2 class="memtitle"><span class="permalink"><a href="#a0157cc89d9db4032c7a8f9159ebaeff3">&#9670;&#160;</a></span>invoke()</h2>
 124
 125 <div class="memitem">
 126 <div class="memproto">
 127 <div class="memtemplate">
 128 template &lt;class T_type , bool I_derives_trackable = std::is_base_of&lt;trackable, T_type&gt;::value&gt; </div>
 129 <table class="mlabels">
 130   <tr>
 131   <td class="mlabels-left">
 132       <table class="memname">
 133         <tr>
 134           <td class="memname">volatile T_type&amp; <a class="el" href="classsigc_1_1volatile__limit__reference.html">sigc::volatile_limit_reference</a>&lt; T_type, I_derives_trackable &gt;::invoke </td>
 135           <td>(</td>
 136           <td class="paramname"></td><td>)</td>
 137           <td> const</td>
 138         </tr>
 139       </table>
 140   </td>
 141   <td class="mlabels-right">
 142 <span class="mlabels"><span class="mlabel">inline</span></span>  </td>
 143   </tr>
 144 </table>
 145 </div><div class="memdoc">
 146
 147 <p>Retrieve the reference. </p>
 148 <p>This is always a reference to the derived instance. </p><dl class="section return"><dt>Returns</dt><dd>The reference. </dd></dl>
 149
 150 </div>
 151 </div>
 152 <a id="a4d67fe2d9d27c326136a9e5ac13a1a75"></a>
 153 <h2 class="memtitle"><span class="permalink"><a href="#a4d67fe2d9d27c326136a9e5ac13a1a75">&#9670;&#160;</a></span>visit()</h2>
 154
 155 <div class="memitem">
 156 <div class="memproto">
 157 <div class="memtemplate">
 158 template &lt;class T_type , bool I_derives_trackable = std::is_base_of&lt;trackable, T_type&gt;::value&gt; </div>
 159 <table class="mlabels">
 160   <tr>
 161   <td class="mlabels-left">
 162       <table class="memname">
 163         <tr>
 164           <td class="memname">const T_type&amp; <a class="el" href="classsigc_1_1volatile__limit__reference.html">sigc::volatile_limit_reference</a>&lt; T_type, I_derives_trackable &gt;::visit </td>
 165           <td>(</td>
 166           <td class="paramname"></td><td>)</td>
 167           <td> const</td>
 168         </tr>
 169       </table>
 170   </td>
 171   <td class="mlabels-right">
 172 <span class="mlabels"><span class="mlabel">inline</span></span>  </td>
 173   </tr>
 174 </table>
 175 </div><div class="memdoc">
 176
 177 <p>Retrieve the entity to visit for <a class="el" href="group__sigcfunctors.html#ga64cb7832acc1e58efb5ffe0b4f5e9404" title="This function performs a functor on each of the targets of a functor.">visit_each()</a>. </p>
 178 <p>Depending on the template specialization, this is either a derived reference, or <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a>&amp; if T_type derives from <a class="el" href="structsigc_1_1trackable.html" title="Base class for objects with auto-disconnection.">sigc::trackable</a>. </p><dl class="section return"><dt>Returns</dt><dd>The reference. </dd></dl>
 179
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