1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Macro BOOST_VMD_ASSERT</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. The Variadic Macro Data Library 1.9"> 8<link rel="up" href="header/boost/vmd/assert_hpp.html" title="Header <boost/vmd/assert.hpp>"> 9<link rel="prev" href="header/boost/vmd/assert_hpp.html" title="Header <boost/vmd/assert.hpp>"> 10<link rel="next" href="header/boost/vmd/assert_is_array_hpp.html" title="Header <boost/vmd/assert_is_array.hpp>"> 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="header/boost/vmd/assert_hpp.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="header/boost/vmd/assert_hpp.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="header/boost/vmd/assert_is_array_hpp.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="refentry"> 26<a name="BOOST_VMD_ASSERT"></a><div class="titlepage"></div> 27<div class="refnamediv"> 28<h2><span class="refentrytitle">Macro BOOST_VMD_ASSERT</span></h2> 29<p>BOOST_VMD_ASSERT — Conditionally causes an error to be generated. </p> 30</div> 31<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 32<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="header/boost/vmd/assert_hpp.html" title="Header <boost/vmd/assert.hpp>">boost/vmd/assert.hpp</a>> 33 34</span>BOOST_VMD_ASSERT(...)</pre></div> 35<div class="refsect1"> 36<a name="idm46219109603088"></a><h2>Description</h2> 37<p>... = variadic parameters, maximum of 2 will be considered. Any variadic parameters beyond the maximum of 2 are just ignored.</p> 38<p>The first variadic parameter is:</p> 39<p>cond = A condition that determines whether an assertion occurs. Valid values range from 0 to BOOST_PP_LIMIT_MAG.</p> 40<p>The second variadic parameter (optional) is:</p> 41<p>errstr = An error string for generating a compiler error when using the VC++ compiler. The VC++ compiler is incapable of producing a preprocessor error so when the 'cond' is 0, a compiler error is generated by outputting C++ code in the form of:</p> 42<pre class="programlisting"><span class="keyword">typedef</span> <span class="keyword">char</span> <span class="identifier">errstr</span><span class="special">[</span><span class="special">-</span><span class="number">1</span><span class="special">]</span><span class="special">;</span> 43</pre> 44<p>The errstr defaults to BOOST_VMD_ASSERT_ERROR if not supplied. It is only relevant for VC++.</p> 45<p>returns = If cond expands to 0, this macro causes an error. Otherwise, it expands to nothing. For all compilers other than Visual C++ the error is a preprocessing error. For Visual C++ the error is caused by output invalid C++: this error could be masked if the invalid output is ignored by a macro which invokes this macro. </p> 46</div> 47</div> 48<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 49<td align="left"></td> 50<td align="right"><div class="copyright-footer">Copyright © 2010-2017 Tropic Software 51 East Inc</div></td> 52</tr></table> 53<hr> 54<div class="spirit-nav"> 55<a accesskey="p" href="header/boost/vmd/assert_hpp.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="header/boost/vmd/assert_hpp.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="header/boost/vmd/assert_is_array_hpp.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 56</div> 57</body> 58</html> 59
