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26<div class="refentry"> 27<a name="boost.signals2.shared_connection_block"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Class shared_connection_block</span></h2> 30<p>boost::signals2::shared_connection_block — Blocks a connection between a signal and a slot.</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../signals2/reference.html#header.boost.signals2.shared_connection_block_hpp" title="Header <boost/signals2/shared_connection_block.hpp>">boost/signals2/shared_connection_block.hpp</a>> 34 35</span> 36<span class="keyword">class</span> <a class="link" href="shared_connection_block.html" title="Class shared_connection_block">shared_connection_block</a> <span class="special">{</span> 37<span class="keyword">public</span><span class="special">:</span> 38 <span class="comment">// <a class="link" href="shared_connection_block.html#boost.signals2.shared_connection_blockconstruct-copy-destruct">construct/copy/destruct</a></span> 39 <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_3-bb"><span class="identifier">shared_connection_block</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="connection.html" title="Class connection">boost::signals2::connection</a> <span class="special">&</span> <span class="special">=</span> <span class="identifier">connection</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> 40 <span class="keyword">bool</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">)</span><span class="special">;</span> 41 <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_4-bb"><span class="identifier">shared_connection_block</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">signals2</span><span class="special">::</span><span class="identifier">shared_connection_block</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 42 shared_connection_block& 43 <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_6-bb"><span class="keyword">operator</span><span class="special">=</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">signals2</span><span class="special">::</span><span class="identifier">shared_connection_block</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 44 <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_5-bb"><span class="special">~</span><span class="identifier">shared_connection_block</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 45 46 <span class="comment">// <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7-bb">connection blocking</a></span> 47 <span class="keyword">void</span> <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_1-bb"><span class="identifier">unblock</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 48 <span class="keyword">void</span> <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_2-bb"><span class="identifier">block</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 49 <span class="keyword">bool</span> <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_3-bb"><span class="identifier">blocking</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 50 51 <span class="comment">// <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_8-bb">miscellaneous methods</a></span> 52 <a class="link" href="connection.html" title="Class connection">boost::signals2::connection</a> <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_8_1-bb"><span class="identifier">connection</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 53<span class="special">}</span><span class="special">;</span></pre></div> 54<div class="refsect1"> 55<a name="id-1.3.36.6.9.3.4"></a><h2>Description</h2> 56<p>A <code class="computeroutput">shared_connection_block</code> object blocks a 57 connection, preventing the associated slot from executing when the 58 associated signal is invoked. The connection will remain 59 blocked until every <code class="computeroutput">shared_connection_block</code> that references 60 the connection 61 releases its block. A <code class="computeroutput">shared_connection_block</code> releases 62 its block when it is destroyed or its 63 <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_1-bb">unblock</a> method is called.</p> 64<p>A <code class="computeroutput">shared_connection_block</code> is safe to use even 65 after the <a class="link" href="connection.html" title="Class connection">signals2::connection</a> object it was constructed 66 from has been destroyed, or the connection it references has been 67 disconnected.</p> 68<p> 69 Note, blocking a connection does not guarantee the associated slot 70 has finished execution if it is already in the process of being run 71 when the connection block goes into effect. This is similar 72 to the behaviour of disconnect, in that blocking a connection 73 will not wait for the connection's associated slot to complete execution. 74 This situation may arise in a multi-threaded environment if the 75 connection block goes into effect concurrently with signal invocation, 76 or in a single-threaded environment if a slot blocks its own 77 connection. 78 </p> 79<div class="refsect2"> 80<a name="id-1.3.36.6.9.3.4.5"></a><h3> 81<a name="boost.signals2.shared_connection_blockconstruct-copy-destruct"></a><code class="computeroutput">shared_connection_block</code> 82 public 83 construct/copy/destruct</h3> 84<div class="orderedlist"><ol class="orderedlist" type="1"> 85<li class="listitem"> 86<pre class="literallayout"><a name="id-1_3_36_6_8_4_1_1_3-bb"></a><span class="identifier">shared_connection_block</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="connection.html" title="Class connection">boost::signals2::connection</a> <span class="special">&</span> conn <span class="special">=</span> <span class="identifier">connection</span><span class="special">(</span><span class="special">)</span><span class="special">,</span> 87 <span class="keyword">bool</span> initially_blocking <span class="special">=</span> <span class="keyword">true</span><span class="special">)</span><span class="special">;</span></pre> 88<div class="variablelist"><table border="0" class="variablelist compact"> 89<colgroup> 90<col align="left" valign="top"> 91<col> 92</colgroup> 93<tbody> 94<tr> 95<td><p><span class="term">Effects:</span></p></td> 96<td> 97<p>Creates a <code class="computeroutput">shared_connection_block</code> which can block 98 the connection referenced by <code class="computeroutput">conn</code>. The <code class="computeroutput">shared_connection_block</code> 99 will initially block the connection if and only if the 100 <code class="computeroutput">initially_blocking</code> 101 parameter is <code class="computeroutput">true</code>. The block on the connection may be released 102 by calling the <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_1-bb">unblock</a> method, 103 or destroying the <code class="computeroutput">shared_connection_block</code> object.</p> 104<p>Default construction of a <code class="computeroutput">shared_connection_block</code> results in a 105 <code class="computeroutput">shared_connection_block</code> which references the NULL connection. 106 Such a <code class="computeroutput">shared_connection_block</code> is safe to use, though not 107 particularly useful until it is assigned another 108 <code class="computeroutput">shared_connection_block</code> which references a real connection. 109 </p> 110</td> 111</tr> 112<tr> 113<td><p><span class="term">Postconditions:</span></p></td> 114<td><p><code class="computeroutput">this->blocking() == initially_blocking</code></p></td> 115</tr> 116</tbody> 117</table></div> 118</li> 119<li class="listitem"> 120<pre class="literallayout"><a name="id-1_3_36_6_8_4_1_1_4-bb"></a><span class="identifier">shared_connection_block</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">signals2</span><span class="special">::</span><span class="identifier">shared_connection_block</span> <span class="special">&</span> other<span class="special">)</span><span class="special">;</span></pre> 121<div class="variablelist"><table border="0" class="variablelist compact"> 122<colgroup> 123<col align="left" valign="top"> 124<col> 125</colgroup> 126<tbody> 127<tr> 128<td><p><span class="term">Effects:</span></p></td> 129<td><p> 130 Copy constructs a <code class="computeroutput">shared_connection_block</code> which references 131 the same connection as <code class="computeroutput">other</code>. 132 </p></td> 133</tr> 134<tr> 135<td><p><span class="term">Postconditions:</span></p></td> 136<td> 137<p><code class="computeroutput">this->connection() == other.connection()</code></p> 138<p><code class="computeroutput">this->blocking() == other.blocking()</code></p> 139</td> 140</tr> 141</tbody> 142</table></div> 143</li> 144<li class="listitem"> 145<pre class="literallayout">shared_connection_block& 146<a name="id-1_3_36_6_8_4_1_1_6-bb"></a><span class="keyword">operator</span><span class="special">=</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">signals2</span><span class="special">::</span><span class="identifier">shared_connection_block</span> <span class="special">&</span> rhs<span class="special">)</span><span class="special">;</span></pre> 147<div class="variablelist"><table border="0" class="variablelist compact"> 148<colgroup> 149<col align="left" valign="top"> 150<col> 151</colgroup> 152<tbody> 153<tr> 154<td><p><span class="term">Effects:</span></p></td> 155<td><p> 156 Makes <code class="computeroutput">this</code> reference the same connection as <code class="computeroutput">rhs</code>. 157 </p></td> 158</tr> 159<tr> 160<td><p><span class="term">Postconditions:</span></p></td> 161<td> 162<p><code class="computeroutput">this->connection() == rhs.connection()</code></p> 163<p><code class="computeroutput">this->blocking() == rhs.blocking()</code></p> 164</td> 165</tr> 166<tr> 167<td><p><span class="term">Throws:</span></p></td> 168<td><p>Will not throw.</p></td> 169</tr> 170</tbody> 171</table></div> 172</li> 173<li class="listitem"> 174<pre class="literallayout"><a name="id-1_3_36_6_8_4_1_1_5-bb"></a><span class="special">~</span><span class="identifier">shared_connection_block</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 175<div class="variablelist"><table border="0" class="variablelist compact"> 176<colgroup> 177<col align="left" valign="top"> 178<col> 179</colgroup> 180<tbody><tr> 181<td><p><span class="term">Effects:</span></p></td> 182<td><p>If <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_3-bb">blocking</a>() is true, releases the connection block.</p></td> 183</tr></tbody> 184</table></div> 185</li> 186</ol></div> 187</div> 188<div class="refsect2"> 189<a name="id-1.3.36.6.9.3.4.6"></a><h3> 190<a name="id-1_3_36_6_8_4_1_1_7-bb"></a><code class="computeroutput">shared_connection_block</code> connection blocking</h3> 191<div class="orderedlist"><ol class="orderedlist" type="1"> 192<li class="listitem"> 193<pre class="literallayout"><span class="keyword">void</span> <a name="id-1_3_36_6_8_4_1_1_7_1-bb"></a><span class="identifier">unblock</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 194<div class="variablelist"><table border="0" class="variablelist compact"> 195<colgroup> 196<col align="left" valign="top"> 197<col> 198</colgroup> 199<tbody> 200<tr> 201<td><p><span class="term">Effects:</span></p></td> 202<td><p>If <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_3-bb">blocking</a>() is true, releases the connection block. 203 Note, the connection may remain blocked due to 204 other <code class="computeroutput">shared_connection_block</code> objects.</p></td> 205</tr> 206<tr> 207<td><p><span class="term">Postconditions:</span></p></td> 208<td><p><code class="computeroutput">this->blocking() == false</code>.</p></td> 209</tr> 210</tbody> 211</table></div> 212</li> 213<li class="listitem"> 214<pre class="literallayout"><span class="keyword">void</span> <a name="id-1_3_36_6_8_4_1_1_7_2-bb"></a><span class="identifier">block</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 215<div class="variablelist"><table border="0" class="variablelist compact"> 216<colgroup> 217<col align="left" valign="top"> 218<col> 219</colgroup> 220<tbody> 221<tr> 222<td><p><span class="term">Effects:</span></p></td> 223<td><p>If <a class="link" href="shared_connection_block.html#id-1_3_36_6_8_4_1_1_7_3-bb">blocking</a>() is false, reasserts a block on 224 the connection.</p></td> 225</tr> 226<tr> 227<td><p><span class="term">Postconditions:</span></p></td> 228<td><p><code class="computeroutput">this->blocking() == true</code>.</p></td> 229</tr> 230</tbody> 231</table></div> 232</li> 233<li class="listitem"> 234<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_36_6_8_4_1_1_7_3-bb"></a><span class="identifier">blocking</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 235<div class="variablelist"><table border="0" class="variablelist compact"> 236<colgroup> 237<col align="left" valign="top"> 238<col> 239</colgroup> 240<tbody> 241<tr> 242<td><p><span class="term">Returns:</span></p></td> 243<td><p><code class="computeroutput">true</code> if <code class="computeroutput">this</code> is asserting a block on the connection.</p></td> 244</tr> 245<tr> 246<td><p><span class="term">Notes:</span></p></td> 247<td><p><code class="computeroutput">this->blocking() == true</code> implies <code class="computeroutput"><a class="link" href="connection.html#id-1_3_36_6_2_1_1_1_9_1-bb">connection::blocked</a>() == true</code> 248 for the connection. However, <code class="computeroutput">this->blocking() == false</code> does not necessarily imply 249 <code class="computeroutput">connection::blocked() == false</code>, since the connection may be 250 blocked by another <code class="computeroutput">shared_connection_block</code> object.</p></td> 251</tr> 252</tbody> 253</table></div> 254</li> 255</ol></div> 256</div> 257<div class="refsect2"> 258<a name="id-1.3.36.6.9.3.4.7"></a><h3> 259<a name="id-1_3_36_6_8_4_1_1_8-bb"></a><code class="computeroutput">shared_connection_block</code> miscellaneous methods</h3> 260<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 261<pre class="literallayout"><a class="link" href="connection.html" title="Class connection">boost::signals2::connection</a> <a name="id-1_3_36_6_8_4_1_1_8_1-bb"></a><span class="identifier">connection</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 262<div class="variablelist"><table border="0" class="variablelist compact"> 263<colgroup> 264<col align="left" valign="top"> 265<col> 266</colgroup> 267<tbody><tr> 268<td><p><span class="term">Returns:</span></p></td> 269<td><p>A connection object for the connection referenced by <code class="computeroutput">this</code>.</p></td> 270</tr></tbody> 271</table></div> 272</li></ol></div> 273</div> 274</div> 275</div> 276<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 277<td align="left"></td> 278<td align="right"><div class="copyright-footer">Copyright © 2001-2004 Douglas Gregor<br>Copyright © 2007-2009 Frank Mori Hess<p>Distributed under the Boost 279 Software License, Version 1.0. (See accompanying file 280 <code class="filename">LICENSE_1_0.txt</code> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</p> 281</div></td> 282</tr></table> 283<hr> 284<div class="spirit-nav"> 285<a accesskey="p" href="optional__1_3_36_6_7_1_1_2.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../signals2/reference.html#header.boost.signals2.shared_connection_block_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="signal.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 286</div> 287</body> 288</html> 289
