| <!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Strict//EN' |
| 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd'> |
| <html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en' lang='en'> |
| <head> |
| <meta http-equiv='Content-Type' content='text/html; charset=utf-8'/> |
| <title>integrating boost exception in existing exception class hierarchies</title> |
| <link href='reno.css' type='text/css' rel='stylesheet'/> |
| </head> |
| <body> |
| <div class="body-0"> |
| <div class="body-1"> |
| <div class="body-2"> |
| <div> |
| <div id="boost_logo"> |
| <a href="http://www.boost.org"><img style="border:0" src="../../../boost.png" alt="Boost" width="277" height="86"/></a> |
| </div> |
| <h1>Boost Exception</h1> |
| </div> |
| <!-- Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc. --> |
| <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying --> |
| <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> |
| <div class="RenoIncludeDIV"><div class="RenoAutoDIV"><h2>Integrating Boost Exception in Existing Exception Class Hierarchies</h2> |
| </div> |
| <p>Some exception hierarchies can not be modified to make boost::<span class="RenoLink"><a href="exception.html">exception</a></span> a base type. In this case, the <span class="RenoLink"><a href="enable_error_info.html">enable_error_info</a></span> function template can be used to make exception objects derive from boost::<span class="RenoLink"><a href="exception.html">exception</a></span> anyway. Here is an example:</p> |
| <pre>#include <<span class="RenoLink"><a href="boost_exception_all_hpp.html">boost/exception/all.hpp</a></span>> |
| #include <stdexcept> |
| |
| typedef boost::<span class="RenoLink"><a href="error_info.html">error_info</a></span><struct tag_std_range_min,size_t> std_range_min; |
| typedef boost::<span class="RenoLink"><a href="error_info.html">error_info</a></span><struct tag_std_range_max,size_t> std_range_max; |
| typedef boost::<span class="RenoLink"><a href="error_info.html">error_info</a></span><struct tag_std_range_index,size_t> std_range_index; |
| |
| template <class T> |
| class |
| my_container |
| { |
| public: |
| |
| size_t size() const; |
| |
| T const & |
| operator[]( size_t i ) const |
| { |
| if( i > size() ) |
| throw boost::<span class="RenoLink"><a href="enable_error_info.html">enable_error_info</a></span>(std::range_error("Index out of range")) << |
| std_range_min(0) << |
| std_range_max(size()) << |
| std_range_index(i); |
| //.... |
| } |
| }; |
| </pre> |
| <p>The call to <span class="RenoLink"><a href="enable_error_info.html">enable_error_info</a></span><T> gets us an object of <i>unspecified type</i> which is guaranteed to derive from both boost::<span class="RenoLink"><a href="exception.html">exception</a></span> and T. This makes it possible to use <span class="RenoLink"><a href="exception_operator_shl.html">operator<<</a></span> to store additional information in the exception object. The exception can be intercepted as T &, so existing exception handling will not break. It can also be intercepted as boost::<span class="RenoLink"><a href="exception.html">exception</a></span> &, so that <span class="RenoLink"><a href="tutorial_transporting_data.html">more information can be added to the exception at a later time</a></span>.</p> |
| </div><div class="RenoAutoDIV"><div class="RenoHR"><hr/></div> |
| See also: <span class="RenoPageList"><a href="boost-exception.html">Boost Exception</a> | <a href="motivation.html">Motivation</a></span> |
| </div> |
| <!-- Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc. --> |
| <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying --> |
| <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> |
| <div id="footer"> |
| <p> |
| <a class="logo" href="http://jigsaw.w3.org/css-validator/check/referer"><img class="logo_pic" src="valid-css.png" alt="Valid CSS" height="31" width="88"/></a> |
| <a class="logo" href="http://validator.w3.org/check?uri=referer"><img class="logo_pic" src="valid-xhtml.png" alt="Valid XHTML 1.0" height="31" width="88"/></a> |
| <small>Copyright (c) 2006-2009 by Emil Dotchevski and Reverge Studios, Inc.<br/> |
| Distributed under the <a href="http://www.boost.org/LICENSE_1_0.txt">Boost Software License, Version 1.0</a>.</small> |
| </p> |
| </div> |
| </div> |
| </div> |
| </div> |
| </body> |
| </html> |
