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| 3 | <title>Compilers corner</title><link rel="stylesheet" href="boostbook.css" type="text/css"><meta name="generator" content="DocBook XSL-NS Stylesheets V1.75.2"><link rel="home" href="index.html" title="Meta State Machine (MSM)"><link rel="up" href="ch04.html" title="Chapter 4. Performance / Compilers"><link rel="prev" href="ch04s04.html" title="Limitations"><link rel="next" href="ch05.html" title="Chapter 5. Questions & Answers, tips"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"> Compilers corner </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04s04.html">Prev</a> </td><th width="60%" align="center">Chapter 4. Performance / Compilers</th><td width="20%" align="right"> <a accesskey="n" href="ch05.html">Next</a></td></tr></table><hr></div><div class="sect1" title="Compilers corner"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="d0e2873"></a> Compilers corner </h2></div></div></div><p>Compilers are sometimes full of surprises and such strange errors happened in | |
| 4 | the course of the development that I wanted to list the most fun for readers’ | |
| 5 | entertainment.</p><p><span class="underline">VC8</span>: </p><pre class="programlisting">template <class StateType> | |
| 6 | typename ::boost::enable_if< | |
| 7 | typename ::boost::mpl::and_< | |
| 8 | typename ::boost::mpl::not_< | |
| 9 | typename has_exit_pseudo_states<StateType>::type | |
| 10 | >::type, | |
| 11 | typename ::boost::mpl::not_< | |
| 12 | typename is_pseudo_exit<StateType>::type | |
| 13 | >::type | |
| 14 | >::type, | |
| 15 | BaseState*>::type </pre><p>I get the following error:</p><p>error C2770: invalid explicit template argument(s) for '`global | |
| 16 | namespace'::boost::enable_if<...>::...' </p><p>If I now remove the first “::” in ::boost::mpl , the compiler shuts up. So in | |
| 17 | this case, it is not possible to follow Boost’s guidelines.</p><p><span class="underline">VC9</span>:</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>This one is my all times’ favorite. Do you know why the exit | |
| 18 | pseudo states are referenced in the transition table with a | |
| 19 | “submachine::exit_pt” ? Because “exit” will crash the compiler. | |
| 20 | “Exit” is not possible either because it will crash the compiler on | |
| 21 | one machine, but not on another (the compiler was installed from the | |
| 22 | same disk).</p></li><li class="listitem"><p>Sometimes, removing a policy crashes the compiler, so some | |
| 23 | versions are defining a dummy policy called WorkaroundVC9.</p></li><li class="listitem"><p>Typeof: While g++ and VC9 compile “standard” state machines in | |
| 24 | comparable times, Typeof (while in both ways natively supported) | |
| 25 | seems to behave in a quadratic complexity with VC9 and VC10.</p></li><li class="listitem"><p>eUML: in case of a compiler crash, changing the order of state | |
| 26 | definitions (first states without entry or exit) sometimes solves | |
| 27 | the problem.</p></li></ul></div><p><span class="underline">g++ 4.x</span>: Boring compiler, almost all is | |
| 28 | working almost as expected. Being not a language lawyer I am unsure about the | |
| 29 | following “Typeof problem”. VC9 and g++ disagree on the question if you can | |
| 30 | derive from the BOOST_TYPEOF generated type without first defining a typedef. I | |
| 31 | will be thankful for an answer on this. I only found two ways to break the compiler:</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Add more eUML constructs until something explodes (especially with | |
| 32 | g++-4.4) </p></li><li class="listitem"><p>The build_terminate function uses 2 mpl::push_back instead of | |
| 33 | mpl::insert_range because g++ would not accept insert_range.</p></li></ul></div><p>You can test your compiler’s decltype implementation with the <a class="link" href="examples/CompilerStressTestEuml.cpp" target="_top">following stress | |
| 34 | test</a> and reactivate the commented-out code until the compiler | |
| 35 | crashes.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch04s04.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch04.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch05.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"> Limitations </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 5. Questions & Answers, tips</td></tr></table></div></body></html> |