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Add BOOST_ASSERT_MSG. Add macros to configure output stream.

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[SVN r68414]
This commit is contained in:
Beman Dawes
2014-01-02 16:13:21 +02:00
committed by Peter Dimov
parent dd8edeacda
commit fada0c5125
3 changed files with 188 additions and 14 deletions
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assert.html
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@@ -17,36 +17,89 @@
<td colspan="2" height="64">&nbsp;</td>
</tr>
</table>
<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>&lt;boost/assert.hpp&gt;</STRONG> defines the macro <b>BOOST_ASSERT</b>,
which is similar to the standard <STRONG>assert</STRONG> macro defined in <STRONG>&lt;cassert&gt;</STRONG>.
The macro is intended to be used in Boost libraries.
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>When the macro <STRONG>BOOST_DISABLE_ASSERTS</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
<P>If the macro <STRONG>BOOST_DISABLE_ASSERTS</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</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>When the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</STRONG>
<P>If the macro <STRONG>BOOST_ENABLE_ASSERT_HANDLER</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</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>&lt;boost/assert.hpp&gt;</STRONG>
as</P>
<pre>
namespace boost
<blockquote>
<pre>namespace boost
{
void assertion_failed(char const * expr, char const * function, char const * file, long line);
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>&lt;cassert&gt;</STRONG>, <STRONG>&lt;boost/assert.hpp&gt;</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>&lt;boost/assert.hpp&gt;</STRONG> defines the macro <b>BOOST_ASSERT_MSG</b>,
which is similar to the standard <STRONG>assert</STRONG> macro defined in <STRONG>&lt;cassert&gt;</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_MSG_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>&lt;boost/assert.hpp&gt;</STRONG>
to specify a different output stream.&nbsp; </P>
<P>If the macro <STRONG>BOOST_ENABLE_ASSERT_MSG_HANDLER</STRONG> is defined when <STRONG>&lt;boost/assert.hpp&gt;</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>&lt;boost/assert.hpp&gt;</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>&lt;cassert&gt;</STRONG>, <STRONG>&lt;boost/assert.hpp&gt;</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>&lt;boost/assert.hpp&gt;</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
@@ -54,8 +107,9 @@ void assertion_failed(char const * expr, char const * function, char const * fil
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. Distributed under the Boost Software
<small>Copyright © 2002, 2007 by Peter Dimov.&nbsp; 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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