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>Prerequisites - 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="./index.html"><img src="./images/prev.png" alt="Prev"></a> 11 <a accesskey="u" href="./index.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="./build.html"><img src="./images/next.png" alt="Next"></a></div><div id="content"> 13 14 <div class="titlepage"><div><div><h1 style="clear: both">Prerequisites</h1></div></div></div> 15<p>Outcome is a header-only C++ 14 library known to work well on the latest 16point releases of these compiler-platform combinations or better:</p> 17 18<ul> 19<li>clang 4.0.1 (LLVM) [FreeBSD, Linux, OS X]</li> 20<li>GCC 6.5 [Linux]</li> 21<li>Visual Studio 2017.9 [Windows]</li> 22<li>XCode 9 [MacOS]</li> 23</ul> 24 25<p>For non-Windows non-POSIX platforms (typically embedded systems), Outcome 26is usable in its Outcome.Experimental form with the macro <code>BOOST_OUTCOME_SYSTEM_ERROR2_NOT_POSIX</code> 27defined.</p> 28 29<p>It is worth turning on C++ 17 or C++ 20 if you can, as there are many usability and 30performance improvements. Any Concepts TS or Coroutines TS implemented 31by your compiler is automatically detected and used.</p> 32 33<p>Partially working compilers (this was last updated January 2019):</p> 34 35<ul> 36<li>clang 3.5 - 3.9 can compile varying degrees of the test suite, the 37problem is lack of complete and unbuggy C++ 14 language support.</li> 38<li>Older point releases of GCCs 7 and 8 have internal compiler error bugs 39in their constexpr implementation which tend to be triggered by using 40Outcome in constexpr. If you don’t use Outcome in constexpr, you won’t 41see these problems. If you need your GCC to not ICE, upgrade to the 42very latest point release, the constexpr ICE has been since fixed.</li> 43<li>Early editions of Visual Studio 2017 have many corner case problems. 44The latest point release, VS2017.9, only has a few known problems, 45and should be relatively unsurprising for most use cases.</li> 46</ul> 47 48<hr /> 49 50<p>“C++ 14” compilers which do not work, and will not work until their 51maintainers fix them:</p> 52 53<ul> 54<li>GCC 5, due to a bug in nested template variables parsing which was fixed 55in GCC 6. I appreciate that this upsets a lot of users. Please raise your 56upset at <a href="https://gcc.gnu.org/bugzilla/">https://gcc.gnu.org/bugzilla/</a>. In the meantime, you can get fairly 57far in Outcome with even clang 3.5.</li> 58<li>Any compiler which uses the libstdc++ version which comes with GCC 5, as it does 59not implement enough of the C++ 14 standard library for Outcome to compile.</li> 60</ul> 61 62 63 64 </div><p><small>Last revised: February 25, 2020 at 11:15:13 UTC</small></p> 65<hr> 66<div class="spirit-nav"> 67<a accesskey="p" href="./index.html"><img src="./images/prev.png" alt="Prev"></a> 68 <a accesskey="u" href="./index.html"><img src="./images/up.png" alt="Up"></a> 69 <a accesskey="h" href="./index.html"><img src="./images/home.png" alt="Home"></a><a accesskey="n" href="./build.html"><img src="./images/next.png" alt="Next"></a></div></body> 70</html> 71
