1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Unbuffered Channel</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Chapter 1. Fiber"> 8<link rel="up" href="../channels.html" title="Channels"> 9<link rel="prev" href="buffered_channel.html" title="Buffered Channel"> 10<link rel="next" href="../futures.html" title="Futures"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="buffered_channel.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../channels.html"><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="../futures.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="fiber.synchronization.channels.unbuffered_channel"></a><a class="link" href="unbuffered_channel.html" title="Unbuffered Channel">Unbuffered 28 Channel</a> 29</h4></div></div></div> 30<p> 31 <span class="bold"><strong>Boost.Fiber</strong></span> provides template <code class="computeroutput"><span class="identifier">unbuffered_channel</span></code> suitable to synchonize 32 fibers (running on same or different threads) via synchronous message passing. 33 A fiber waiting to consume an value will block until the value is produced. 34 If a fiber attempts to send a value through an unbuffered channel and no 35 fiber is waiting to receive the value, the channel will block the sending 36 fiber. 37 </p> 38<p> 39 The unbuffered channel acts as an <code class="computeroutput"><span class="identifier">rendezvous</span> 40 <span class="identifier">point</span></code>. 41 </p> 42<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="keyword">int</span> <span class="special">></span> <span class="identifier">channel_t</span><span class="special">;</span> 43 44<span class="keyword">void</span> <span class="identifier">send</span><span class="special">(</span> <span class="identifier">channel_t</span> <span class="special">&</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">{</span> 45 <span class="keyword">for</span> <span class="special">(</span> <span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="number">5</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span> 46 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="identifier">i</span><span class="special">);</span> 47 <span class="special">}</span> 48 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> 49<span class="special">}</span> 50 51<span class="keyword">void</span> <span class="identifier">recv</span><span class="special">(</span> <span class="identifier">channel_t</span> <span class="special">&</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">{</span> 52 <span class="keyword">int</span> <span class="identifier">i</span><span class="special">;</span> 53 <span class="keyword">while</span> <span class="special">(</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">channel_op_status</span><span class="special">::</span><span class="identifier">success</span> <span class="special">==</span> <span class="identifier">chan</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">i</span><span class="special">)</span> <span class="special">)</span> <span class="special">{</span> 54 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"received "</span> <span class="special"><<</span> <span class="identifier">i</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 55 <span class="special">}</span> 56<span class="special">}</span> 57 58<span class="identifier">channel_t</span> <span class="identifier">chan</span><span class="special">{</span> <span class="number">1</span> <span class="special">};</span> 59<span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">fiber</span> <span class="identifier">f1</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">bind</span><span class="special">(</span> <span class="identifier">send</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">)</span> <span class="special">);</span> 60<span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">fiber</span> <span class="identifier">f2</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">bind</span><span class="special">(</span> <span class="identifier">recv</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">)</span> <span class="special">);</span> 61 62<span class="identifier">f1</span><span class="special">.</span><span class="identifier">join</span><span class="special">();</span> 63<span class="identifier">f2</span><span class="special">.</span><span class="identifier">join</span><span class="special">();</span> 64</pre> 65<p> 66 Range-for syntax is supported: 67 </p> 68<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="keyword">int</span> <span class="special">></span> <span class="identifier">channel_t</span><span class="special">;</span> 69 70<span class="keyword">void</span> <span class="identifier">foo</span><span class="special">(</span> <span class="identifier">channel_t</span> <span class="special">&</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">{</span> 71 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">1</span><span class="special">);</span> 72 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">1</span><span class="special">);</span> 73 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">2</span><span class="special">);</span> 74 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">3</span><span class="special">);</span> 75 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">5</span><span class="special">);</span> 76 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">8</span><span class="special">);</span> 77 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span> <span class="number">12</span><span class="special">);</span> 78 <span class="identifier">chan</span><span class="special">.</span><span class="identifier">close</span><span class="special">();</span> 79<span class="special">}</span> 80 81<span class="keyword">void</span> <span class="identifier">bar</span><span class="special">(</span> <span class="identifier">channel_t</span> <span class="special">&</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">{</span> 82 <span class="keyword">for</span> <span class="special">(</span> <span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">value</span> <span class="special">:</span> <span class="identifier">chan</span><span class="special">)</span> <span class="special">{</span> 83 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">value</span> <span class="special"><<</span> <span class="string">" "</span><span class="special">;</span> 84 <span class="special">}</span> 85 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 86<span class="special">}</span> 87</pre> 88<p> 89 </p> 90<h5> 91<a name="class_unbuffered_channel_bridgehead"></a> 92 <span class="phrase"><a name="class_unbuffered_channel"></a></span> 93 <a class="link" href="unbuffered_channel.html#class_unbuffered_channel">Template 94 <code class="computeroutput">unbuffered_channel<></code></a> 95</h5> 96<p> 97 </p> 98<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fiber</span><span class="special">/</span><span class="identifier">unbuffered_channel</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 99 100<span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> 101<span class="keyword">namespace</span> <span class="identifier">fibers</span> <span class="special">{</span> 102 103<span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">T</span> <span class="special">></span> 104<span class="keyword">class</span> <span class="identifier">unbuffered_channel</span> <span class="special">{</span> 105<span class="keyword">public</span><span class="special">:</span> 106 <span class="keyword">typedef</span> <span class="identifier">T</span> <span class="identifier">value_type</span><span class="special">;</span> 107 108 <span class="keyword">class</span> <span class="identifier">iterator</span><span class="special">;</span> 109 110 <span class="identifier">unbuffered_channel</span><span class="special">();</span> 111 112 <span class="identifier">unbuffered_channel</span><span class="special">(</span> <span class="identifier">unbuffered_channel</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span> 113 <span class="identifier">unbuffered_channel</span> <span class="special">&</span> <span class="keyword">operator</span><span class="special">=(</span> <span class="identifier">unbuffered_channel</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">other</span><span class="special">)</span> <span class="special">=</span> <span class="keyword">delete</span><span class="special">;</span> 114 115 <span class="keyword">void</span> <span class="identifier">close</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span> 116 117 <span class="identifier">channel_op_status</span> <span class="identifier">push</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">va</span><span class="special">);</span> 118 <span class="identifier">channel_op_status</span> <span class="identifier">push</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="special">&&</span> <span class="identifier">va</span><span class="special">);</span> 119 <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Period</span> <span class="special">></span> 120 <span class="identifier">channel_op_status</span> <span class="identifier">push_wait_for</span><span class="special">(</span> 121 <span class="identifier">value_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">va</span><span class="special">,</span> 122 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">duration</span><span class="special"><</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="identifier">Period</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_duration</span><span class="special">);</span> 123 <span class="identifier">channel_op_status</span> <span class="identifier">push_wait_for</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="special">&&</span> <span class="identifier">va</span><span class="special">,</span> 124 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">duration</span><span class="special"><</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="identifier">Period</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_duration</span><span class="special">);</span> 125 <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Duration</span> <span class="special">></span> 126 <span class="identifier">channel_op_status</span> <span class="identifier">push_wait_until</span><span class="special">(</span> 127 <span class="identifier">value_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">va</span><span class="special">,</span> 128 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">time_point</span><span class="special"><</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="identifier">Duration</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_time</span><span class="special">);</span> 129 <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Duration</span> <span class="special">></span> 130 <span class="identifier">channel_op_status</span> <span class="identifier">push_wait_until</span><span class="special">(</span> 131 <span class="identifier">value_type</span> <span class="special">&&</span> <span class="identifier">va</span><span class="special">,</span> 132 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">time_point</span><span class="special"><</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="identifier">Duration</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_time</span><span class="special">);</span> 133 134 <span class="identifier">channel_op_status</span> <span class="identifier">pop</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="special">&</span> <span class="identifier">va</span><span class="special">);</span> 135 <span class="identifier">value_type</span> <span class="identifier">value_pop</span><span class="special">();</span> 136 <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Period</span> <span class="special">></span> 137 <span class="identifier">channel_op_status</span> <span class="identifier">pop_wait_for</span><span class="special">(</span> 138 <span class="identifier">value_type</span> <span class="special">&</span> <span class="identifier">va</span><span class="special">,</span> 139 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">duration</span><span class="special"><</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="identifier">Period</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_duration</span><span class="special">);</span> 140 <span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Duration</span> <span class="special">></span> 141 <span class="identifier">channel_op_status</span> <span class="identifier">pop_wait_until</span><span class="special">(</span> 142 <span class="identifier">value_type</span> <span class="special">&</span> <span class="identifier">va</span><span class="special">,</span> 143 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">time_point</span><span class="special"><</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="identifier">Duration</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_time</span><span class="special">);</span> 144<span class="special">};</span> 145 146<span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">T</span> <span class="special">></span> 147<span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">begin</span><span class="special">(</span> <span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> <span class="identifier">chan</span><span class="special">);</span> 148 149<span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">T</span> <span class="special">></span> 150<span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">end</span><span class="special">(</span> <span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> <span class="identifier">chan</span><span class="special">);</span> 151 152<span class="special">}}</span> 153</pre> 154<h6> 155<a name="fiber.synchronization.channels.unbuffered_channel.h0"></a> 156 <span class="phrase"><a name="fiber.synchronization.channels.unbuffered_channel.constructor"></a></span><a class="link" href="unbuffered_channel.html#fiber.synchronization.channels.unbuffered_channel.constructor">Constructor</a> 157 </h6> 158<pre class="programlisting"><span class="identifier">unbuffered_channel</span><span class="special">();</span> 159</pre> 160<div class="variablelist"> 161<p class="title"><b></b></p> 162<dl class="variablelist"> 163<dt><span class="term">Effects:</span></dt> 164<dd><p> 165 The constructor constructs an object of class <code class="computeroutput"><span class="identifier">unbuffered_channel</span></code>. 166 </p></dd> 167</dl> 168</div> 169<p> 170 </p> 171<h5> 172<a name="unbuffered_channel_close_bridgehead"></a> 173 <span class="phrase"><a name="unbuffered_channel_close"></a></span> 174 <a class="link" href="unbuffered_channel.html#unbuffered_channel_close">Member 175 function <code class="computeroutput">close</code>()</a> 176</h5> 177<p> 178 </p> 179<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">close</span><span class="special">()</span> <span class="keyword">noexcept</span><span class="special">;</span> 180</pre> 181<div class="variablelist"> 182<p class="title"><b></b></p> 183<dl class="variablelist"> 184<dt><span class="term">Effects:</span></dt> 185<dd><p> 186 Deactivates the channel. No values can be put after calling <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">close</span><span class="special">()</span></code>. 187 Fibers blocked in <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">pop</span><span class="special">()</span></code>, <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">pop_wait_for</span><span class="special">()</span></code> or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">pop_wait_until</span><span class="special">()</span></code> will return <code class="computeroutput"><span class="identifier">closed</span></code>. 188 Fibers blocked in <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">value_pop</span><span class="special">()</span></code> will receive an exception. 189 </p></dd> 190<dt><span class="term">Throws:</span></dt> 191<dd><p> 192 Nothing. 193 </p></dd> 194<dt><span class="term">Note:</span></dt> 195<dd><p> 196 <code class="computeroutput"><span class="identifier">close</span><span class="special">()</span></code> 197 is like closing a pipe. It informs waiting consumers that no more 198 values will arrive. 199 </p></dd> 200</dl> 201</div> 202<p> 203 </p> 204<h5> 205<a name="unbuffered_channel_push_bridgehead"></a> 206 <span class="phrase"><a name="unbuffered_channel_push"></a></span> 207 <a class="link" href="unbuffered_channel.html#unbuffered_channel_push">Member 208 function <code class="computeroutput">push</code>()</a> 209</h5> 210<p> 211 </p> 212<pre class="programlisting"><span class="identifier">channel_op_status</span> <span class="identifier">push</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">va</span><span class="special">);</span> 213<span class="identifier">channel_op_status</span> <span class="identifier">push</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="special">&&</span> <span class="identifier">va</span><span class="special">);</span> 214</pre> 215<div class="variablelist"> 216<p class="title"><b></b></p> 217<dl class="variablelist"> 218<dt><span class="term">Effects:</span></dt> 219<dd><p> 220 If channel is closed, returns <code class="computeroutput"><span class="identifier">closed</span></code>. 221 Otherwise enqueues the value in the channel, wakes up a fiber blocked 222 on <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">pop</span><span class="special">()</span></code>, 223 <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">value_pop</span><span class="special">()</span></code>, 224 <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">pop_wait_for</span><span class="special">()</span></code> 225 or <code class="computeroutput"><span class="keyword">this</span><span class="special">-></span><span class="identifier">pop_wait_until</span><span class="special">()</span></code> 226 and returns <code class="computeroutput"><span class="identifier">success</span></code>. 227 </p></dd> 228<dt><span class="term">Throws:</span></dt> 229<dd><p> 230 Exceptions thrown by copy- or move-operations. 231 </p></dd> 232</dl> 233</div> 234<p> 235 </p> 236<h5> 237<a name="unbuffered_channel_pop_bridgehead"></a> 238 <span class="phrase"><a name="unbuffered_channel_pop"></a></span> 239 <a class="link" href="unbuffered_channel.html#unbuffered_channel_pop">Member 240 function <code class="computeroutput">pop</code>()</a> 241</h5> 242<p> 243 </p> 244<pre class="programlisting"><span class="identifier">channel_op_status</span> <span class="identifier">pop</span><span class="special">(</span> <span class="identifier">value_type</span> <span class="special">&</span> <span class="identifier">va</span><span class="special">);</span> 245</pre> 246<div class="variablelist"> 247<p class="title"><b></b></p> 248<dl class="variablelist"> 249<dt><span class="term">Effects:</span></dt> 250<dd><p> 251 Dequeues a value from the channel. If the channel is empty, the fiber 252 gets suspended until at least one new item is <code class="computeroutput"><span class="identifier">push</span><span class="special">()</span></code>ed (return value <code class="computeroutput"><span class="identifier">success</span></code> 253 and <code class="computeroutput"><span class="identifier">va</span></code> contains dequeued 254 value) or the channel gets <code class="computeroutput"><span class="identifier">close</span><span class="special">()</span></code>d (return value <code class="computeroutput"><span class="identifier">closed</span></code>). 255 </p></dd> 256<dt><span class="term">Throws:</span></dt> 257<dd><p> 258 Exceptions thrown by copy- or move-operations. 259 </p></dd> 260</dl> 261</div> 262<p> 263 </p> 264<h5> 265<a name="unbuffered_channel_value_pop_bridgehead"></a> 266 <span class="phrase"><a name="unbuffered_channel_value_pop"></a></span> 267 <a class="link" href="unbuffered_channel.html#unbuffered_channel_value_pop">Member 268 function <code class="computeroutput">value_pop</code>()</a> 269</h5> 270<p> 271 </p> 272<pre class="programlisting"><span class="identifier">value_type</span> <span class="identifier">value_pop</span><span class="special">();</span> 273</pre> 274<div class="variablelist"> 275<p class="title"><b></b></p> 276<dl class="variablelist"> 277<dt><span class="term">Effects:</span></dt> 278<dd><p> 279 Dequeues a value from the channel. If the channel is empty, the fiber 280 gets suspended until at least one new item is <code class="computeroutput"><span class="identifier">push</span><span class="special">()</span></code>ed or the channel gets <code class="computeroutput"><span class="identifier">close</span><span class="special">()</span></code>d 281 (which throws an exception). 282 </p></dd> 283<dt><span class="term">Throws:</span></dt> 284<dd><p> 285 <code class="computeroutput"><span class="identifier">fiber_error</span></code> if <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code> 286 is closed or by copy- or move-operations. 287 </p></dd> 288<dt><span class="term">Error conditions:</span></dt> 289<dd><p> 290 <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">errc</span><span class="special">::</span><span class="identifier">operation_not_permitted</span></code> 291 </p></dd> 292</dl> 293</div> 294<p> 295 </p> 296<h5> 297<a name="unbuffered_channel_pop_wait_for_bridgehead"></a> 298 <span class="phrase"><a name="unbuffered_channel_pop_wait_for"></a></span> 299 <a class="link" href="unbuffered_channel.html#unbuffered_channel_pop_wait_for">Member 300 function <code class="computeroutput">pop_wait_for</code>()</a> 301</h5> 302<p> 303 </p> 304<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Period</span> <span class="special">></span> 305<span class="identifier">channel_op_status</span> <span class="identifier">pop_wait_for</span><span class="special">(</span> 306 <span class="identifier">value_type</span> <span class="special">&</span> <span class="identifier">va</span><span class="special">,</span> 307 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">duration</span><span class="special"><</span> <span class="identifier">Rep</span><span class="special">,</span> <span class="identifier">Period</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_duration</span><span class="special">)</span> 308</pre> 309<div class="variablelist"> 310<p class="title"><b></b></p> 311<dl class="variablelist"> 312<dt><span class="term">Effects:</span></dt> 313<dd><p> 314 Accepts <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">duration</span></code> and internally computes 315 a timeout time as (system time + <code class="computeroutput"><span class="identifier">timeout_duration</span></code>). 316 If channel is not empty, immediately dequeues a value from the channel. 317 Otherwise the fiber gets suspended until at least one new item is 318 <code class="computeroutput"><span class="identifier">push</span><span class="special">()</span></code>ed 319 (return value <code class="computeroutput"><span class="identifier">success</span></code> 320 and <code class="computeroutput"><span class="identifier">va</span></code> contains dequeued 321 value), or the channel gets <code class="computeroutput"><span class="identifier">close</span><span class="special">()</span></code>d (return value <code class="computeroutput"><span class="identifier">closed</span></code>), 322 or the system time reaches the computed timeout time (return value 323 <code class="computeroutput"><span class="identifier">timeout</span></code>). 324 </p></dd> 325<dt><span class="term">Throws:</span></dt> 326<dd><p> 327 timeout-related exceptions or by copy- or move-operations. 328 </p></dd> 329</dl> 330</div> 331<p> 332 </p> 333<h5> 334<a name="unbuffered_channel_pop_wait_until_bridgehead"></a> 335 <span class="phrase"><a name="unbuffered_channel_pop_wait_until"></a></span> 336 <a class="link" href="unbuffered_channel.html#unbuffered_channel_pop_wait_until">Member 337 function <code class="computeroutput">pop_wait_until</code>()</a> 338</h5> 339<p> 340 </p> 341<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Duration</span> <span class="special">></span> 342<span class="identifier">channel_op_status</span> <span class="identifier">pop_wait_until</span><span class="special">(</span> 343 <span class="identifier">value_type</span> <span class="special">&</span> <span class="identifier">va</span><span class="special">,</span> 344 <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">time_point</span><span class="special"><</span> <span class="identifier">Clock</span><span class="special">,</span> <span class="identifier">Duration</span> <span class="special">></span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">timeout_time</span><span class="special">)</span> 345</pre> 346<div class="variablelist"> 347<p class="title"><b></b></p> 348<dl class="variablelist"> 349<dt><span class="term">Effects:</span></dt> 350<dd><p> 351 Accepts a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">time_point</span><span class="special"><</span> 352 <span class="identifier">Clock</span><span class="special">,</span> 353 <span class="identifier">Duration</span> <span class="special">></span></code>. 354 If channel is not empty, immediately dequeues a value from the channel. 355 Otherwise the fiber gets suspended until at least one new item is 356 <code class="computeroutput"><span class="identifier">push</span><span class="special">()</span></code>ed 357 (return value <code class="computeroutput"><span class="identifier">success</span></code> 358 and <code class="computeroutput"><span class="identifier">va</span></code> contains dequeued 359 value), or the channel gets <code class="computeroutput"><span class="identifier">close</span><span class="special">()</span></code>d (return value <code class="computeroutput"><span class="identifier">closed</span></code>), 360 or the system time reaches the passed <code class="computeroutput"><span class="identifier">time_point</span></code> 361 (return value <code class="computeroutput"><span class="identifier">timeout</span></code>). 362 </p></dd> 363<dt><span class="term">Throws:</span></dt> 364<dd><p> 365 timeout-related exceptions or by copy- or move-operations. 366 </p></dd> 367</dl> 368</div> 369<h6> 370<a name="fiber.synchronization.channels.unbuffered_channel.h1"></a> 371 <span class="phrase"><a name="fiber.synchronization.channels.unbuffered_channel.non_member_function__code__phrase_role__identifier__begin__phrase__phrase_role__special_____phrase___phrase_role__identifier__unbuffered_channel__phrase__phrase_role__special___lt___phrase___phrase_role__identifier__t__phrase___phrase_role__special___gt___phrase___phrase_role__special___amp____phrase___code_"></a></span><a class="link" href="unbuffered_channel.html#fiber.synchronization.channels.unbuffered_channel.non_member_function__code__phrase_role__identifier__begin__phrase__phrase_role__special_____phrase___phrase_role__identifier__unbuffered_channel__phrase__phrase_role__special___lt___phrase___phrase_role__identifier__t__phrase___phrase_role__special___gt___phrase___phrase_role__special___amp____phrase___code_">Non-member 372 function <code class="computeroutput"><span class="identifier">begin</span><span class="special">(</span> 373 <span class="identifier">unbuffered_channel</span><span class="special"><</span> 374 <span class="identifier">T</span> <span class="special">></span> 375 <span class="special">&)</span></code></a> 376 </h6> 377<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">T</span> <span class="special">></span> 378<span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">begin</span><span class="special">(</span> <span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&);</span> 379</pre> 380<div class="variablelist"> 381<p class="title"><b></b></p> 382<dl class="variablelist"> 383<dt><span class="term">Returns:</span></dt> 384<dd><p> 385 Returns a range-iterator (input-iterator). 386 </p></dd> 387</dl> 388</div> 389<h6> 390<a name="fiber.synchronization.channels.unbuffered_channel.h2"></a> 391 <span class="phrase"><a name="fiber.synchronization.channels.unbuffered_channel.non_member_function__code__phrase_role__identifier__end__phrase__phrase_role__special_____phrase___phrase_role__identifier__unbuffered_channel__phrase__phrase_role__special___lt___phrase___phrase_role__identifier__t__phrase___phrase_role__special___gt___phrase___phrase_role__special___amp____phrase___code_"></a></span><a class="link" href="unbuffered_channel.html#fiber.synchronization.channels.unbuffered_channel.non_member_function__code__phrase_role__identifier__end__phrase__phrase_role__special_____phrase___phrase_role__identifier__unbuffered_channel__phrase__phrase_role__special___lt___phrase___phrase_role__identifier__t__phrase___phrase_role__special___gt___phrase___phrase_role__special___amp____phrase___code_">Non-member 392 function <code class="computeroutput"><span class="identifier">end</span><span class="special">(</span> 393 <span class="identifier">unbuffered_channel</span><span class="special"><</span> 394 <span class="identifier">T</span> <span class="special">></span> 395 <span class="special">&)</span></code></a> 396 </h6> 397<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">T</span> <span class="special">></span> 398<span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">R</span> <span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">end</span><span class="special">(</span> <span class="identifier">unbuffered_channel</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&);</span> 399</pre> 400<div class="variablelist"> 401<p class="title"><b></b></p> 402<dl class="variablelist"> 403<dt><span class="term">Returns:</span></dt> 404<dd><p> 405 Returns an end range-iterator (input-iterator). 406 </p></dd> 407</dl> 408</div> 409</div> 410<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 411<td align="left"></td> 412<td align="right"><div class="copyright-footer">Copyright © 2013 Oliver Kowalke<p> 413 Distributed under the Boost Software License, Version 1.0. (See accompanying 414 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>) 415 </p> 416</div></td> 417</tr></table> 418<hr> 419<div class="spirit-nav"> 420<a accesskey="p" href="buffered_channel.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../channels.html"><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="../futures.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 421</div> 422</body> 423</html> 424
