1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>when_all until first exception</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="../when_all_functionality.html" title="when_all functionality"> 9<link rel="prev" href="when_all__return_values.html" title="when_all, return values"> 10<link rel="next" href="wait_all__collecting_all_exceptions.html" title="wait_all, collecting all exceptions"> 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="when_all__return_values.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../when_all_functionality.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="wait_all__collecting_all_exceptions.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.when_any.when_all_functionality.when_all_until_first_exception"></a><a class="link" href="when_all_until_first_exception.html" title="when_all until first exception">when_all 28 until first exception</a> 29</h4></div></div></div> 30<p> 31 Naturally, just as with <a class="link" href="../when_any/when_any__produce_first_outcome__whether_result_or_exception.html#wait_first_outcome"><code class="computeroutput"><span class="identifier">wait_first_outcome</span><span class="special">()</span></code></a>, 32 we can elaborate <a class="link" href="when_all__return_values.html#wait_all_values"><code class="computeroutput"><span class="identifier">wait_all_values</span><span class="special">()</span></code></a> and <a class="link" href="when_all__return_values.html#wait_all_values_source"><code class="computeroutput"><span class="identifier">wait_all_values_source</span><span class="special">()</span></code></a> 33 by passing <code class="computeroutput"><span class="identifier">future</span><span class="special"><</span> 34 <span class="identifier">T</span> <span class="special">></span></code> 35 instead of plain <code class="computeroutput"><span class="identifier">T</span></code>. 36 </p> 37<p> 38 <a name="wait_all_until_error"></a><code class="computeroutput"><span class="identifier">wait_all_until_error</span><span class="special">()</span></code> pops that <code class="computeroutput"><span class="identifier">future</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span></code> and calls its <a class="link" href="../../synchronization/futures/future.html#future_get"><code class="computeroutput">future::get()</code></a>: 39 </p> 40<p> 41</p> 42<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Fns</span> <span class="special">></span> 43<span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">result_of</span><span class="special"><</span> <span class="identifier">Fn</span><span class="special">()</span> <span class="special">>::</span><span class="identifier">type</span> <span class="special">></span> 44<span class="identifier">wait_all_until_error</span><span class="special">(</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">function</span><span class="special">,</span> <span class="identifier">Fns</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">functions</span><span class="special">)</span> <span class="special">{</span> 45 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">count</span><span class="special">(</span> <span class="number">1</span> <span class="special">+</span> <span class="keyword">sizeof</span> <span class="special">...</span> <span class="special">(</span> <span class="identifier">functions</span><span class="special">)</span> <span class="special">);</span> 46 <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">result_of</span><span class="special"><</span> <span class="identifier">Fn</span><span class="special">()</span> <span class="special">>::</span><span class="identifier">type</span> <span class="identifier">return_t</span><span class="special">;</span> 47 <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">future</span><span class="special"><</span> <span class="identifier">return_t</span> <span class="special">></span> <span class="identifier">future_t</span><span class="special">;</span> 48 <span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">return_t</span> <span class="special">></span> <span class="identifier">vector_t</span><span class="special">;</span> 49 <span class="identifier">vector_t</span> <span class="identifier">results</span><span class="special">;</span> 50 <span class="identifier">results</span><span class="special">.</span><span class="identifier">reserve</span><span class="special">(</span> <span class="identifier">count</span><span class="special">);</span> 51 52 <span class="comment">// get channel</span> 53 <span class="identifier">std</span><span class="special">::</span><span class="identifier">shared_ptr</span><span class="special"><</span> 54 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">buffered_channel</span><span class="special"><</span> <span class="identifier">future_t</span> <span class="special">></span> <span class="special">></span> <span class="identifier">chan</span><span class="special">(</span> 55 <span class="identifier">wait_all_until_error_source</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special"><</span> <span class="identifier">Fn</span> <span class="special">>(</span> <span class="identifier">function</span><span class="special">),</span> 56 <span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special"><</span> <span class="identifier">Fns</span> <span class="special">>(</span> <span class="identifier">functions</span><span class="special">)</span> <span class="special">...</span> <span class="special">)</span> <span class="special">);</span> 57 <span class="comment">// fill results vector</span> 58 <span class="identifier">future_t</span> <span class="identifier">future</span><span class="special">;</span> 59 <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">future</span><span class="special">)</span> <span class="special">)</span> <span class="special">{</span> 60 <span class="identifier">results</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span> <span class="identifier">future</span><span class="special">.</span><span class="identifier">get</span><span class="special">()</span> <span class="special">);</span> 61 <span class="special">}</span> 62 <span class="comment">// return vector to caller</span> 63 <span class="keyword">return</span> <span class="identifier">results</span><span class="special">;</span> 64<span class="special">}</span> 65</pre> 66<p> 67 </p> 68<p> 69 For example: 70 </p> 71<p> 72</p> 73<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">thrown</span><span class="special">;</span> 74<span class="keyword">try</span> <span class="special">{</span> 75 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">></span> <span class="identifier">values</span> <span class="special">=</span> <span class="identifier">wait_all_until_error</span><span class="special">(</span> 76 <span class="special">[](){</span> <span class="keyword">return</span> <span class="identifier">sleeper</span><span class="special">(</span><span class="string">"waue_late"</span><span class="special">,</span> <span class="number">150</span><span class="special">);</span> <span class="special">},</span> 77 <span class="special">[](){</span> <span class="keyword">return</span> <span class="identifier">sleeper</span><span class="special">(</span><span class="string">"waue_middle"</span><span class="special">,</span> <span class="number">100</span><span class="special">,</span> <span class="keyword">true</span><span class="special">);</span> <span class="special">},</span> 78 <span class="special">[](){</span> <span class="keyword">return</span> <span class="identifier">sleeper</span><span class="special">(</span><span class="string">"waue_early"</span><span class="special">,</span> <span class="number">50</span><span class="special">);</span> <span class="special">});</span> 79<span class="special">}</span> <span class="keyword">catch</span> <span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">exception</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">e</span><span class="special">)</span> <span class="special">{</span> 80 <span class="identifier">thrown</span> <span class="special">=</span> <span class="identifier">e</span><span class="special">.</span><span class="identifier">what</span><span class="special">();</span> 81<span class="special">}</span> 82<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"wait_all_until_error(fail) threw '"</span> <span class="special"><<</span> <span class="identifier">thrown</span> 83 <span class="special"><<</span> <span class="string">"'"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 84</pre> 85<p> 86 </p> 87<p> 88 <a name="wait_all_until_error_source"></a>Naturally this complicates the 89 API for <code class="computeroutput"><span class="identifier">wait_all_until_error_source</span><span class="special">()</span></code>. The caller must both retrieve a <code class="computeroutput"><span class="identifier">future</span><span class="special"><</span> 90 <span class="identifier">T</span> <span class="special">></span></code> 91 and call its <code class="computeroutput"><span class="identifier">get</span><span class="special">()</span></code> 92 method. It would, of course, be possible to return a façade over the consumer 93 end of the queue that would implicitly perform the <code class="computeroutput"><span class="identifier">get</span><span class="special">()</span></code> and return a simple <code class="computeroutput"><span class="identifier">T</span></code> 94 (or throw). 95 </p> 96<p> 97 The implementation is just as you would expect. Notice, however, that we 98 can reuse <a class="link" href="../when_any/when_any__produce_first_outcome__whether_result_or_exception.html#wait_first_outcome_impl"><code class="computeroutput"><span class="identifier">wait_first_outcome_impl</span><span class="special">()</span></code></a>, passing the <code class="computeroutput"><span class="identifier">nqueue</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span></code> rather than <code class="computeroutput"><span class="identifier">queue</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span></code>. 99 </p> 100<p> 101</p> 102<pre class="programlisting"><span class="comment">// Return a shared_ptr<buffered_channel<future<T>>> from which the caller can</span> 103<span class="comment">// get() each new result as it arrives, until 'closed'.</span> 104<span class="keyword">template</span><span class="special"><</span> <span class="keyword">typename</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">typename</span> <span class="special">...</span> <span class="identifier">Fns</span> <span class="special">></span> 105<span class="identifier">std</span><span class="special">::</span><span class="identifier">shared_ptr</span><span class="special"><</span> 106 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">buffered_channel</span><span class="special"><</span> 107 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fibers</span><span class="special">::</span><span class="identifier">future</span><span class="special"><</span> 108 <span class="keyword">typename</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">result_of</span><span class="special"><</span> <span class="identifier">Fn</span><span class="special">()</span> <span class="special">>::</span><span class="identifier">type</span> <span class="special">></span> <span class="special">></span> <span class="special">></span> 109<span class="identifier">wait_all_until_error_source</span><span class="special">(</span> <span class="identifier">Fn</span> <span class="special">&&</span> <span class="identifier">function</span><span class="special">,</span> <span class="identifier">Fns</span> <span class="special">&&</span> <span class="special">...</span> <span class="identifier">functions</span><span class="special">)</span> <span class="special">{</span> 110 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">count</span><span class="special">(</span> <span class="number">1</span> <span class="special">+</span> <span class="keyword">sizeof</span> <span class="special">...</span> <span class="special">(</span> <span class="identifier">functions</span><span class="special">)</span> <span class="special">);</span> 111 <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">result_of</span><span class="special"><</span> <span class="identifier">Fn</span><span class="special">()</span> <span class="special">>::</span><span class="identifier">type</span> <span class="identifier">return_t</span><span class="special">;</span> 112 <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">future</span><span class="special"><</span> <span class="identifier">return_t</span> <span class="special">></span> <span class="identifier">future_t</span><span class="special">;</span> 113 <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">buffered_channel</span><span class="special"><</span> <span class="identifier">future_t</span> <span class="special">></span> <span class="identifier">channel_t</span><span class="special">;</span> 114 <span class="comment">// make the channel</span> 115 <span class="keyword">auto</span> <span class="identifier">chanp</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">make_shared</span><span class="special"><</span> <span class="identifier">channel_t</span> <span class="special">>(</span> <span class="number">64</span><span class="special">)</span> <span class="special">);</span> 116 <span class="comment">// and make an nchannel facade to close it after 'count' items</span> 117 <span class="keyword">auto</span> <span class="identifier">ncp</span><span class="special">(</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">make_shared</span><span class="special"><</span> <span class="identifier">nchannel</span><span class="special"><</span> <span class="identifier">future_t</span> <span class="special">></span> <span class="special">>(</span> <span class="identifier">chanp</span><span class="special">,</span> <span class="identifier">count</span><span class="special">)</span> <span class="special">);</span> 118 <span class="comment">// pass that nchannel facade to all the relevant fibers</span> 119 <span class="identifier">wait_first_outcome_impl</span><span class="special"><</span> <span class="identifier">return_t</span> <span class="special">>(</span> <span class="identifier">ncp</span><span class="special">,</span> 120 <span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special"><</span> <span class="identifier">Fn</span> <span class="special">>(</span> <span class="identifier">function</span><span class="special">),</span> 121 <span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special"><</span> <span class="identifier">Fns</span> <span class="special">>(</span> <span class="identifier">functions</span><span class="special">)</span> <span class="special">...</span> <span class="special">);</span> 122 <span class="comment">// then return the channel for consumer</span> 123 <span class="keyword">return</span> <span class="identifier">chanp</span><span class="special">;</span> 124<span class="special">}</span> 125</pre> 126<p> 127 </p> 128<p> 129 For example: 130 </p> 131<p> 132</p> 133<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">future</span><span class="special"><</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">></span> <span class="identifier">future_t</span><span class="special">;</span> 134<span class="identifier">std</span><span class="special">::</span><span class="identifier">shared_ptr</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">buffered_channel</span><span class="special"><</span> <span class="identifier">future_t</span> <span class="special">></span> <span class="special">></span> <span class="identifier">chan</span> <span class="special">=</span> 135 <span class="identifier">wait_all_until_error_source</span><span class="special">(</span> 136 <span class="special">[](){</span> <span class="keyword">return</span> <span class="identifier">sleeper</span><span class="special">(</span><span class="string">"wauess_third"</span><span class="special">,</span> <span class="number">150</span><span class="special">);</span> <span class="special">},</span> 137 <span class="special">[](){</span> <span class="keyword">return</span> <span class="identifier">sleeper</span><span class="special">(</span><span class="string">"wauess_second"</span><span class="special">,</span> <span class="number">100</span><span class="special">);</span> <span class="special">},</span> 138 <span class="special">[](){</span> <span class="keyword">return</span> <span class="identifier">sleeper</span><span class="special">(</span><span class="string">"wauess_first"</span><span class="special">,</span> <span class="number">50</span><span class="special">);</span> <span class="special">});</span> 139<span class="identifier">future_t</span> <span class="identifier">future</span><span class="special">;</span> 140<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">future</span><span class="special">)</span> <span class="special">)</span> <span class="special">{</span> 141 <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">value</span><span class="special">(</span> <span class="identifier">future</span><span class="special">.</span><span class="identifier">get</span><span class="special">()</span> <span class="special">);</span> 142 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"wait_all_until_error_source(success) => '"</span> <span class="special"><<</span> <span class="identifier">value</span> 143 <span class="special"><<</span> <span class="string">"'"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 144<span class="special">}</span> 145</pre> 146<p> 147 </p> 148</div> 149<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 150<td align="left"></td> 151<td align="right"><div class="copyright-footer">Copyright © 2013 Oliver Kowalke<p> 152 Distributed under the Boost Software License, Version 1.0. (See accompanying 153 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>) 154 </p> 155</div></td> 156</tr></table> 157<hr> 158<div class="spirit-nav"> 159<a accesskey="p" href="when_all__return_values.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../when_all_functionality.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="wait_all__collecting_all_exceptions.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 160</div> 161</body> 162</html> 163
