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| </th><td width="20%" align="right"> <a accesskey="n" href="verbose_termination.html">Next</a></td></tr></table><hr /></div><div class="chapter" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title"><a id="manual.support.termination"></a>Chapter 6. Termination</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="sect1"><a href="verbose_termination.html">Verbose Terminate Handler</a></span></dt></dl></div><div class="sect1" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="support.termination.handlers"></a>Termination Handlers</h2></div></div></div><p> |
| Not many changes here to <code class="filename">cstdlib</code>. You should note that the |
| <code class="function">abort()</code> function does not call the |
| destructors of automatic nor static objects, so if you're |
| depending on those to do cleanup, it isn't going to happen. |
| (The functions registered with <code class="function">atexit()</code> |
| don't get called either, so you can forget about that |
| possibility, too.) |
| </p><p> |
| The good old <code class="function">exit()</code> function can be a bit |
| funky, too, until you look closer. Basically, three points to |
| remember are: |
| </p><div class="orderedlist"><ol type="1"><li><p> |
| Static objects are destroyed in reverse order of their creation. |
| </p></li><li><p> |
| Functions registered with <code class="function">atexit()</code> are called in |
| reverse order of registration, once per registration call. |
| (This isn't actually new.) |
| </p></li><li><p> |
| The previous two actions are “<span class="quote">interleaved,</span>” that is, |
| given this pseudocode: |
| </p><pre class="programlisting"> |
| extern "C or C++" void f1 (void); |
| extern "C or C++" void f2 (void); |
| |
| static Thing obj1; |
| atexit(f1); |
| static Thing obj2; |
| atexit(f2); |
| </pre><p> |
| then at a call of <code class="function">exit()</code>, |
| <code class="varname">f2</code> will be called, then |
| <code class="varname">obj2</code> will be destroyed, then |
| <code class="varname">f1</code> will be called, and finally |
| <code class="varname">obj1</code> will be destroyed. If |
| <code class="varname">f1</code> or <code class="varname">f2</code> allow an |
| exception to propagate out of them, Bad Things happen. |
| </p></li></ol></div><p> |
| Note also that <code class="function">atexit()</code> is only required to store 32 |
| functions, and the compiler/library might already be using some of |
| those slots. If you think you may run out, we recommend using |
| the <code class="function">xatexit</code>/<code class="function">xexit</code> combination from <code class="literal">libiberty</code>, which has no such limit. |
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