diff options
Diffstat (limited to 'libcult/documentation/eh')
| -rw-r--r-- | libcult/documentation/eh/index.xhtml | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/libcult/documentation/eh/index.xhtml b/libcult/documentation/eh/index.xhtml new file mode 100644 index 0000000..7847c11 --- /dev/null +++ b/libcult/documentation/eh/index.xhtml @@ -0,0 +1,106 @@ +<?xml version="1.0" encoding="iso-8859-1"?> +<!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" lang="en" xml:lang="en"> + +<!-- + +file : documentation/eh/index.xhtml +author : Boris Kolpackov <boris@kolpackov.net> +copyright : Copyright (c) 2005-2010 Boris Kolpackov +license : GNU FDL v1.2; http://kolpackov.net/licenses/fdl-1.2.txt + +--> + +<head> + + <title>libcult/documentation/eh</title> + + <meta name="author" content="Boris Kolpackov"/> + <meta name="copyright" content="© 2005-2010 Boris Kolpackov"/> + <meta name="keywords" content="libcult,c++,exception,handling"/> + <meta name="description" content="libcult/documentation/eh"/> + + <link rel="stylesheet" type="text/css" href="../default.css"/> + +</head> + +<body> + +<div id="navigation"> +<p> +<a href="../.."><code>libcult</code></a> <code>/</code> +<a href=".."><code>documentation</code></a> <code>/</code> +<code>eh</code> +</p> +</div> + +<div id="content"> +<p>The <code>libcult</code> exception handling library defines a base +exception type to be used by the rest of <code>libcult</code>. It has +a very basic interface:</p> + +<pre class="cxx"> +namespace Cult +{ + namespace EH + { + class Exception: public virtual std::exception + { + public: + virtual char const* + what () const throw (); + }; + } +} +</pre> + +<p>It derives from <code>std::exception</code> to allow catching +all exceptions with a single handler. Default implementation of the +<code>what()</code> member function returns type-name of the exception. +</p> + +<p>Every non-trivial library in <em>libcult</em> derives its own +base exception which all library-defined exceptions inherit. This +way you can catch all exceptions from a library with one handler.</p> + +<p>Sometimes it may seem convenient to further partition (by providing +corresponding base classes) exceptions space into <em>logic</em> +exceptions (shared by all implementations) and <em>implementation</em> +exceptions. For example, if you pass an allocator illegal size 0 then +the allocator throws an exception which can be classified as a logic +exception. If, however, you passed valid size but there is not enough +memory then the allocator throws an exception which can be classified +as an implementation exception<sup><a href="#fn1">1</a></sup>.</p> + +<p>The problem with this approach lies in the fact that someone's logic +exception is someone else's implementation exception. Consider, for +instance, a buffer type that is implemented in terms of our allocator. +If the buffer happened to request a memory block of size 0 and let +the exception propagate through the interface boundaries it is no longer +a logic exception.</p> + + +<div id="footnote"> +<hr/> +<p id="fn1"><sup>1</sup> It can be argued that the +<code>NoMemory</code> exception should rather be classified +as logic. However, let's assume there are allocator implementations +that have infinite memory.</p> +</div> + +</div> + +<div id="docinfo"> +<p>Copyright © 2005-2010 <a title="Boris Kolpackov" +href="http://kolpackov.net">Boris Kolpackov</a>.</p> + +<div class="terms"> +Permission is granted to copy, distribute and/or modify this document under +the terms of the <a href="http://kolpackov.net/licenses/fdl-1.2.txt">GNU Free +Documentation License, version 1.2</a>; with no Invariant Sections, no +Front-Cover Texts and no Back-Cover Texts. +</div> +</div> + +</body> +</html> |