1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html><meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 3<title>Before we begin - Boost.Outcome documentation</title> 4<link rel="stylesheet" href="../../css/boost.css" type="text/css"> 5<meta name="generator" content="Hugo 0.52 with Boostdoc theme"> 6<meta name="viewport" content="width=device-width,initial-scale=1.0"/> 7 8<link rel="icon" href="../../images/favicon.ico" type="image/ico"/> 9<body><div class="spirit-nav"> 10<a accesskey="p" href="../../tutorial/essential.html"><img src="../../images/prev.png" alt="Prev"></a> 11 <a accesskey="u" href="../../tutorial/essential.html"><img src="../../images/up.png" alt="Up"></a> 12 <a accesskey="h" href="../../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="../../tutorial/essential/result.html"><img src="../../images/next.png" alt="Next"></a></div><div id="content"> 13 <div class="titlepage"><div><div><h1 style="clear: both">Before we begin</h1></div></div></div> 14 15 16<h2 id="outcome-v2-namespace">Outcome v2 namespace</h2> 17 18<p>It is recommended that you refer to entities from this Outcome v2 via the following namespace alias:</p> 19 20<div class="code-snippet"><div class="highlight"><pre class="chroma"><code class="language-c++" data-lang="c++"><span class="k">namespace</span> <span class="n">outcome</span> <span class="o">=</span> <span class="n">BOOST_OUTCOME_V2_NAMESPACE</span><span class="p">;</span> 21</code></pre></div><a href="https://github.com/boostorg/outcome/tree/master/doc/src/snippets/using_result.cpp#L38" class="code-snippet-url" target="_blank">View this code on Github</a></div> 22 23 24<p>On standalone Outcome only, as patches and modifications are applied to this library, 25namespaces get permuted in order to not to cause binary incompatibility. At some point 26namespace <code>outcome_v2</code> will be defined, and this will be the preferred namespace. 27Until then <code>BOOST_OUTCOME_V2_NAMESPACE</code> denotes the most recently 28updated version, getting closer to <code>outcome_v2</code>.</p> 29 30<p>On Boost.Outcome only, as Boost provides no binary compatibility across releases, 31<code>BOOST_OUTCOME_V2_NAMESPACE</code> always expands into <code>boost::outcome_v2</code>.</p> 32 33<h2 id="online-compilers">Online compilers</h2> 34 35<p>If you’ve never used them before, you will find 36<a href="https://godbolt.org/">Godbolt</a> and <a href="https://wandbox.org/">Wandbox</a> invaluable. 37These let you play with C++ inside your web browser.</p> 38 39<p>Most of the source code snippets in Outcome have a link in their top right to 40the original source code on github. You can copy and paste this source code into 41Godbolt (if you wish to study the assembler generated) or Wandbox (if you 42wish to run the program).</p> 43 44<h3 id="godbolt">Godbolt</h3> 45 46<p>Godbolt is invaluable for visualising online the assembler generated for a 47piece of C++, for all the major compilers and CPU architectures.</p> 48 49<p>Standalone Outcome is built into Godbolt! In the right hand pane toolbar, click the 50libraries dropdown (currently third from the right, looks like a book), find 51Outcome and choose the version you want.</p> 52 53<p>After this is selected, you can <code>#include</code> any of these editions of Outcome:</p> 54 55<dl> 56 <dt><code><outcome-basic.hpp></code></dt> 57 <dd>An inclusion of <code>basic_outcome.hpp</code> + <code>try.hpp</code> which includes as few 58 system headers as possible in order to give an absolute minimum compile time 59 impact edition of Outcome. See <a href="https://github.com/ned14/stl-header-heft">https://github.com/ned14/stl-header-heft</a>. 60 </dd> 61 <dt><code><outcome-experimental.hpp></code></dt> 62 <dd>An inclusion of <code>experimental/status_outcome.hpp</code> + <code>try.hpp</code> which 63 is the low compile time impact of the basic edition combined with 64 <code>status_code</code> from <a href="https://ned14.github.io/status-code/">https://ned14.github.io/status-code/</a>. If you are on an 65 embedded system where binary bloat must be absolutely avoided, and don't 66 mind the potentially unstable <code>status_code</code>, this is definitely the edition 67 for you. 68 </dd> 69 <dt><code><outcome.hpp></code></dt> 70 <dd>An inclusion of <code>outcome.hpp</code> which brings in all the specialisations 71 for the <code>std</code> STL types, plus iostreams support. If you don't know which 72 edition to use, you should use this one, it ought to "just work".</dd> 73</dl> 74 75<p>Here is the first tutorial topic’s source code loaded into Godbolt: <a href="https://godbolt.org/z/p-NAho">https://godbolt.org/z/p-NAho</a></p> 76 77<h3 id="wandbox">Wandbox</h3> 78 79<p>Wandbox lets you place a third party header into a separate tab. It also 80comes with a recent Boost libraries. Either technique can be used to 81explore Outcome.</p> 82 83<p>Here is the first tutorial topic’s source code loaded into Wandbox: <a href="https://wandbox.org/permlink/sJoeKHXSyCU5Avft">https://wandbox.org/permlink/sJoeKHXSyCU5Avft</a></p> 84 85 86 </div><p><small>Last revised: February 09, 2019 at 14:45:47 UTC</small></p> 87<hr> 88<div class="spirit-nav"> 89<a accesskey="p" href="../../tutorial/essential.html"><img src="../../images/prev.png" alt="Prev"></a> 90 <a accesskey="u" href="../../tutorial/essential.html"><img src="../../images/up.png" alt="Up"></a> 91 <a accesskey="h" href="../../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="../../tutorial/essential/result.html"><img src="../../images/next.png" alt="Next"></a></div></body> 92</html> 93
