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  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="boost_asio.reference.basic_signal_set"></a><a class="link" href="basic_signal_set.html" title="basic_signal_set">basic_signal_set</a>
  28 </h3></div></div></div>
  29 <p>
  30         Provides signal functionality.
  31       </p>
  32 <pre class="programlisting">template&lt;
  33     typename <a class="link" href="Executor1.html" title="Executor requirements">Executor</a> = executor&gt;
  34 class basic_signal_set
  35 </pre>
  36 <h5>
  37 <a name="boost_asio.reference.basic_signal_set.h0"></a>
  38         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.types"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.types">Types</a>
  39       </h5>
  40 <div class="informaltable"><table class="table">
  41 <colgroup>
  42 <col>
  43 <col>
  44 </colgroup>
  45 <thead><tr>
  46 <th>
  47                 <p>
  48                   Name
  49                 </p>
  50               </th>
  51 <th>
  52                 <p>
  53                   Description
  54                 </p>
  55               </th>
  56 </tr></thead>
  57 <tbody>
  58 <tr>
  59 <td>
  60                 <p>
  61                   <a class="link" href="basic_signal_set__rebind_executor.html" title="basic_signal_set::rebind_executor"><span class="bold"><strong>rebind_executor</strong></span></a>
  62                 </p>
  63               </td>
  64 <td>
  65                 <p>
  66                   Rebinds the signal set type to another executor.
  67                 </p>
  68               </td>
  69 </tr>
  70 <tr>
  71 <td>
  72                 <p>
  73                   <a class="link" href="basic_signal_set/executor_type.html" title="basic_signal_set::executor_type"><span class="bold"><strong>executor_type</strong></span></a>
  74                 </p>
  75               </td>
  76 <td>
  77                 <p>
  78                   The type of the executor associated with the object.
  79                 </p>
  80               </td>
  81 </tr>
  82 </tbody>
  83 </table></div>
  84 <h5>
  85 <a name="boost_asio.reference.basic_signal_set.h1"></a>
  86         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.member_functions"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.member_functions">Member Functions</a>
  87       </h5>
  88 <div class="informaltable"><table class="table">
  89 <colgroup>
  90 <col>
  91 <col>
  92 </colgroup>
  93 <thead><tr>
  94 <th>
  95                 <p>
  96                   Name
  97                 </p>
  98               </th>
  99 <th>
 100                 <p>
 101                   Description
 102                 </p>
 103               </th>
 104 </tr></thead>
 105 <tbody>
 106 <tr>
 107 <td>
 108                 <p>
 109                   <a class="link" href="basic_signal_set/add.html" title="basic_signal_set::add"><span class="bold"><strong>add</strong></span></a>
 110                 </p>
 111               </td>
 112 <td>
 113                 <p>
 114                   Add a signal to a signal_set.
 115                 </p>
 116               </td>
 117 </tr>
 118 <tr>
 119 <td>
 120                 <p>
 121                   <a class="link" href="basic_signal_set/async_wait.html" title="basic_signal_set::async_wait"><span class="bold"><strong>async_wait</strong></span></a>
 122                 </p>
 123               </td>
 124 <td>
 125                 <p>
 126                   Start an asynchronous operation to wait for a signal to be delivered.
 127                 </p>
 128               </td>
 129 </tr>
 130 <tr>
 131 <td>
 132                 <p>
 133                   <a class="link" href="basic_signal_set/basic_signal_set.html" title="basic_signal_set::basic_signal_set"><span class="bold"><strong>basic_signal_set</strong></span></a>
 134                 </p>
 135               </td>
 136 <td>
 137                 <p>
 138                   Construct a signal set without adding any signals. <br> <span class="silver"> &#8212;</span><br>
 139                   Construct a signal set and add one signal. <br> <span class="silver"> &#8212;</span><br> Construct
 140                   a signal set and add two signals. <br> <span class="silver"> &#8212;</span><br> Construct a signal
 141                   set and add three signals.
 142                 </p>
 143               </td>
 144 </tr>
 145 <tr>
 146 <td>
 147                 <p>
 148                   <a class="link" href="basic_signal_set/cancel.html" title="basic_signal_set::cancel"><span class="bold"><strong>cancel</strong></span></a>
 149                 </p>
 150               </td>
 151 <td>
 152                 <p>
 153                   Cancel all operations associated with the signal set.
 154                 </p>
 155               </td>
 156 </tr>
 157 <tr>
 158 <td>
 159                 <p>
 160                   <a class="link" href="basic_signal_set/clear.html" title="basic_signal_set::clear"><span class="bold"><strong>clear</strong></span></a>
 161                 </p>
 162               </td>
 163 <td>
 164                 <p>
 165                   Remove all signals from a signal_set.
 166                 </p>
 167               </td>
 168 </tr>
 169 <tr>
 170 <td>
 171                 <p>
 172                   <a class="link" href="basic_signal_set/get_executor.html" title="basic_signal_set::get_executor"><span class="bold"><strong>get_executor</strong></span></a>
 173                 </p>
 174               </td>
 175 <td>
 176                 <p>
 177                   Get the executor associated with the object.
 178                 </p>
 179               </td>
 180 </tr>
 181 <tr>
 182 <td>
 183                 <p>
 184                   <a class="link" href="basic_signal_set/remove.html" title="basic_signal_set::remove"><span class="bold"><strong>remove</strong></span></a>
 185                 </p>
 186               </td>
 187 <td>
 188                 <p>
 189                   Remove a signal from a signal_set.
 190                 </p>
 191               </td>
 192 </tr>
 193 <tr>
 194 <td>
 195                 <p>
 196                   <a class="link" href="basic_signal_set/_basic_signal_set.html" title="basic_signal_set::~basic_signal_set"><span class="bold"><strong>~basic_signal_set</strong></span></a>
 197                 </p>
 198               </td>
 199 <td>
 200                 <p>
 201                   Destroys the signal set.
 202                 </p>
 203               </td>
 204 </tr>
 205 </tbody>
 206 </table></div>
 207 <p>
 208         The <a class="link" href="basic_signal_set.html" title="basic_signal_set"><code class="computeroutput">basic_signal_set</code></a>
 209         class provides the ability to perform an asynchronous wait for one or more
 210         signals to occur.
 211       </p>
 212 <h5>
 213 <a name="boost_asio.reference.basic_signal_set.h2"></a>
 214         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.thread_safety"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.thread_safety">Thread
 215         Safety</a>
 216       </h5>
 217 <p>
 218         <span class="emphasis"><em>Distinct</em></span> <span class="emphasis"><em>objects:</em></span> Safe.
 219       </p>
 220 <p>
 221         <span class="emphasis"><em>Shared</em></span> <span class="emphasis"><em>objects:</em></span> Unsafe.
 222       </p>
 223 <h5>
 224 <a name="boost_asio.reference.basic_signal_set.h3"></a>
 225         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.example"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.example">Example</a>
 226       </h5>
 227 <p>
 228         Performing an asynchronous wait:
 229       </p>
 230 <pre class="programlisting">void handler(
 231     const boost::system::error_code&amp; error,
 232     int signal_number)
 233 {
 234   if (!error)
 235   {
 236     // A signal occurred.
 237   }
 238 }
 239
 240 ...
 241
 242 // Construct a signal set registered for process termination.
 243 boost::asio::signal_set signals(my_context, SIGINT, SIGTERM);
 244
 245 // Start an asynchronous wait for one of the signals to occur.
 246 signals.async_wait(handler);
 247 </pre>
 248 <h5>
 249 <a name="boost_asio.reference.basic_signal_set.h4"></a>
 250         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.queueing_of_signal_notifications"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.queueing_of_signal_notifications">Queueing
 251         of signal notifications</a>
 252       </h5>
 253 <p>
 254         If a signal is registered with a signal_set, and the signal occurs when there
 255         are no waiting handlers, then the signal notification is queued. The next
 256         async_wait operation on that signal_set will dequeue the notification. If
 257         multiple notifications are queued, subsequent async_wait operations dequeue
 258         them one at a time. Signal notifications are dequeued in order of ascending
 259         signal number.
 260       </p>
 261 <p>
 262         If a signal number is removed from a signal_set (using the <code class="computeroutput">remove</code>
 263         or <code class="computeroutput">erase</code> member functions) then any queued notifications for
 264         that signal are discarded.
 265       </p>
 266 <h5>
 267 <a name="boost_asio.reference.basic_signal_set.h5"></a>
 268         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.multiple_registration_of_signals"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.multiple_registration_of_signals">Multiple
 269         registration of signals</a>
 270       </h5>
 271 <p>
 272         The same signal number may be registered with different signal_set objects.
 273         When the signal occurs, one handler is called for each signal_set object.
 274       </p>
 275 <p>
 276         Note that multiple registration only works for signals that are registered
 277         using Asio. The application must not also register a signal handler using
 278         functions such as <code class="computeroutput">signal()</code> or <code class="computeroutput">sigaction()</code>.
 279       </p>
 280 <h5>
 281 <a name="boost_asio.reference.basic_signal_set.h6"></a>
 282         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.signal_masking_on_posix_platforms"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.signal_masking_on_posix_platforms">Signal
 283         masking on POSIX platforms</a>
 284       </h5>
 285 <p>
 286         POSIX allows signals to be blocked using functions such as <code class="computeroutput">sigprocmask()</code>
 287         and <code class="computeroutput">pthread_sigmask()</code>. For signals to be delivered, programs
 288         must ensure that any signals registered using signal_set objects are unblocked
 289         in at least one thread.
 290       </p>
 291 <h5>
 292 <a name="boost_asio.reference.basic_signal_set.h7"></a>
 293         <span class="phrase"><a name="boost_asio.reference.basic_signal_set.requirements"></a></span><a class="link" href="basic_signal_set.html#boost_asio.reference.basic_signal_set.requirements">Requirements</a>
 294       </h5>
 295 <p>
 296         <span class="emphasis"><em>Header: </em></span><code class="literal">boost/asio/basic_signal_set.hpp</code>
 297       </p>
 298 <p>
 299         <span class="emphasis"><em>Convenience header: </em></span><code class="literal">boost/asio.hpp</code>
 300       </p>
 301 </div>
 302 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 303 <td align="left"></td>
 304 <td align="right"><div class="copyright-footer">Copyright &#169; 2003-2019 Christopher M. Kohlhoff<p>
 305         Distributed under the Boost Software License, Version 1.0. (See accompanying
 306         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
 307       </p>
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