doc/html/boost_asio/reference/signal_set.html

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