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| <h1>assert.hpp</h1> |
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| <p> |
| <a href="#BOOST_ASSERT">BOOST_ASSERT</a><br> |
| <a href="#BOOST_ASSERT_MSG">BOOST_ASSERT_MSG</a><br> |
| <a href="#BOOST_VERIFY">BOOST_VERIFY</a></p> |
| |
| <h2><a name="BOOST_ASSERT">BOOST_ASSERT</a></h2> |
| <p> |
| The header <STRONG><boost/assert.hpp></STRONG> defines the macro <b>BOOST_ASSERT</b>, |
| which is similar to the standard <STRONG>assert</STRONG> macro defined in <STRONG><cassert></STRONG>. |
| The macro is intended to be used in both Boost libraries and user |
| code. |
| </p> |
| <P>By default, <tt>BOOST_ASSERT(expr)</tt> is equivalent to <tt>assert(expr)</tt>.</P> |
| <P>If the macro <STRONG>BOOST_DISABLE_ASSERTS</STRONG> is defined when <STRONG><boost/assert.hpp></STRONG> |
| is included, <tt>BOOST_ASSERT(expr)</tt> is defined as <tt>((void)0)</tt>. This |
| allows users to selectively disable <STRONG>BOOST_ASSERT</STRONG> without |
| affecting the definition of the standard <STRONG>assert</STRONG>.</P> |
| <P>If the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG><boost/assert.hpp></STRONG> |
| is included, <tt>BOOST_ASSERT(expr)</tt> evaluates <b>expr</b> and, if the |
| result is false, evaluates the expression</P> |
| <blockquote> |
| <P><tt>::boost::assertion_failed(#expr, <a href="current_function.html">BOOST_CURRENT_FUNCTION</a>, |
| __FILE__, __LINE__)</tt></P> |
| </blockquote> |
| <P><STRONG>assertion_failed</STRONG> is declared in <STRONG><boost/assert.hpp></STRONG> |
| as</P> |
| <blockquote> |
| <pre>namespace boost |
| { |
| void assertion_failed(char const * expr, char const * function, char const * file, long line); |
| } |
| </pre> |
| </blockquote> |
| <p>but it is never defined. The user is expected to supply an appropriate |
| definition.</p> |
| <P>As is the case with <STRONG><cassert></STRONG>, <STRONG><boost/assert.hpp></STRONG> |
| can be included multiple times in a single translation unit. <STRONG>BOOST_ASSERT</STRONG> |
| will be redefined each time as specified above.</P> |
| |
| <h2><a name="BOOST_ASSERT_MSG">BOOST_ASSERT_MSG</a></h2> |
| <p> |
| The header <STRONG><boost/assert.hpp></STRONG> defines the macro <b>BOOST_ASSERT_MSG</b>, |
| which is similar to the standard <STRONG>assert</STRONG> macro defined in <STRONG><cassert></STRONG>, |
| but with an additional macro parameter supplying an error message. The macro is intended to be used in both Boost libraries |
| and user code. |
| </p> |
| <P> <tt>BOOST_ASSERT_MSG(expr, msg)</tt> is equivalent to <code> |
| ((void)0)</code> if <b>BOOST_DISABLE_ASSERTS</b> or <b>NDEBUG</b> are |
| defined or <code>expr</code> evaluates to <code>true</code>. If those |
| macros and <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> are not |
| defined, and <code>expr</code> evaluates to <code>false</code>, an error |
| message that includes <tt>#expr</tt>, <tt>msg</tt>, <tt> <a href="current_function.html">BOOST_CURRENT_FUNCTION</a></tt>, <tt> |
| __FILE__</tt>, and <tt>__LINE__</tt> is sent to output stream <b> |
| BOOST_ASSERT_MSG_OSTREAM</b> |
| and <code>std::abort()</code> is called.</P> |
| <P> <b>BOOST_ASSERT_MSG_OSTREAM</b> defines the output stream. It defaults to <code>std::cerr</code>. |
| Integrated development environments (IDE's) like Microsoft Visual Studio |
| may produce easier to understand output if messages go to a different |
| stream, such as <code>std::cout</code>. Users may define <b>BOOST_ASSERT_MSG_OSTREAM</b> before including <STRONG><boost/assert.hpp></STRONG> |
| to specify a different output stream. </P> |
| <P>If the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG><boost/assert.hpp></STRONG> |
| is included, instead of sending a error message to an output |
| stream, this expression is evaluated</P> |
| <blockquote> |
| <P><tt>::boost::assertion_failed_msg(#expr, msg, <a href="current_function.html">BOOST_CURRENT_FUNCTION</a>, |
| __FILE__, __LINE__)</tt></P> |
| </blockquote> |
| <P><STRONG>assertion_failed_msg</STRONG> is declared in <STRONG><boost/assert.hpp></STRONG> |
| as</P> |
| <blockquote> |
| <pre>namespace boost |
| { |
| void assertion_failed_msg(char const * expr, char const * msg, char const * function, char const * file, long line); |
| } |
| </pre> |
| </blockquote> |
| <p>but it is never defined. The user is expected to supply an appropriate |
| definition.</p> |
| <P>As is the case with <STRONG><cassert></STRONG>, <STRONG><boost/assert.hpp></STRONG> |
| can be included multiple times in a single translation unit. <STRONG>BOOST_ASSERT_MSG</STRONG> |
| will be redefined each time as specified above.</P> |
| |
| <h2><a name="BOOST_VERIFY">BOOST_VERIFY</a></h2> |
| <p><STRONG><boost/assert.hpp></STRONG> also defines the macro <STRONG>BOOST_VERIFY</STRONG>. |
| It has exactly the same behavior as <STRONG>BOOST_ASSERT</STRONG>, except that |
| the expression that is passed to <STRONG>BOOST_VERIFY</STRONG> is always |
| evaluated. This is useful when the asserted expression has desirable side |
| effects; it can also help suppress warnings about unused variables when the |
| only use of the variable is inside an assertion.</p> |
| <p><br> |
| <small>Copyright © 2002, 2007 by Peter Dimov. Copyright © 2011 |
| by Beman Dawes. Distributed under the Boost Software |
| License, Version 1.0. See accompanying file <A href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</A> |
| or copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>.</small></p> |
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