|
|
|
|
|
<!DOCTYPE html>
|
|
|
|
|
|
|
|
|
|
|
|
<html >
|
|
|
|
|
|
<head>
|
|
|
|
|
|
<meta charset="utf-8" />
|
|
|
|
|
|
<title>Coding Conventions — SeisComP Release documentation</title>
|
|
|
|
|
|
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
|
|
|
|
|
|
<link rel="stylesheet" href="../_static/seiscomp.css" type="text/css" />
|
|
|
|
|
|
<link rel="stylesheet" type="text/css" href="../_static/graphviz.css" />
|
|
|
|
|
|
<script type="text/javascript" src="../_static/seiscomp.js"></script>
|
|
|
|
|
|
<script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
|
|
|
|
|
|
<script src="../_static/jquery.js"></script>
|
|
|
|
|
|
<script src="../_static/underscore.js"></script>
|
|
|
|
|
|
<script src="../_static/doctools.js"></script>
|
|
|
|
|
|
<script src="../_static/language_data.js"></script>
|
|
|
|
|
|
<link rel="shortcut icon" href="../_static/favicon.ico"/>
|
|
|
|
|
|
<link rel="index" title="Index" href="../genindex.html" />
|
|
|
|
|
|
<link rel="search" title="Search" href="../search.html" />
|
|
|
|
|
|
<link rel="next" title="Unit Testing" href="tests.html" />
|
|
|
|
|
|
<link rel="prev" title="Style Guide for Documentation" href="style-guide.html" />
|
|
|
|
|
|
</head>
|
|
|
|
|
|
<body>
|
|
|
|
|
|
<div class="header">
|
|
|
|
|
|
<div class="container">
|
|
|
|
|
|
<div class="brand">
|
|
|
|
|
|
<img class="logo" src="../_static/brands/seiscomp/text/white.svg"/>
|
|
|
|
|
|
<!-- span class="title">SeisComP Release</span -->
|
|
|
|
|
|
<span class="version">5.3.0</span>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="nav">
|
|
|
|
|
|
<div class="container">
|
|
|
|
|
|
<div class="content"><a class="pull-right" id="sidebar-toggle">TOC</a>
|
|
|
|
|
|
|
|
|
|
|
|
<div class="related" role="navigation" aria-label="related navigation">
|
|
|
|
|
|
<ul>
|
|
|
|
|
|
<li class="right">
|
|
|
|
|
|
<a href="../genindex.html" title="General Index"
|
|
|
|
|
|
accesskey="I">
|
|
|
|
|
|
index
|
|
|
|
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li class="right">
|
|
|
|
|
|
<a href="tests.html" title="Unit Testing"
|
|
|
|
|
|
accesskey="N">
|
|
|
|
|
|
next
|
|
|
|
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li class="right">
|
|
|
|
|
|
<a href="style-guide.html" title="Style Guide for Documentation"
|
|
|
|
|
|
accesskey="P">
|
|
|
|
|
|
previous
|
|
|
|
|
|
</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li class="nav-item nav-item-0">
|
|
|
|
|
|
<a href="../index.html">Home</a>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="container">
|
|
|
|
|
|
<div class="fitted content" id="anchors-container">
|
|
|
|
|
|
<div class="body" role="main">
|
|
|
|
|
|
|
|
|
|
|
|
<div class="section" id="coding-conventions">
|
|
|
|
|
|
<span id="id1"></span><h1>Coding Conventions<a class="headerlink" href="#coding-conventions" title="Permalink to this headline">¶</a></h1>
|
|
|
|
|
|
<div class="section" id="code-style">
|
|
|
|
|
|
<h2>Code Style<a class="headerlink" href="#code-style" title="Permalink to this headline">¶</a></h2>
|
|
|
|
|
|
<div class="section" id="formatting">
|
|
|
|
|
|
<h3>Formatting<a class="headerlink" href="#formatting" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>For C++ always use tab indentation. In case of line break white spaces have to be
|
|
|
|
|
|
used to fill the space. The recommended tab width is 4 characters.</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="c1">// Tabs are visualized with '>' and spaces with '.'</span>
|
|
|
|
|
|
<span class="kt">int</span> <span class="nf">myFunction</span><span class="p">()</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="o">></span> <span class="kt">int</span> <span class="n">a</span> <span class="o">=</span> <span class="mi">5</span><span class="p">;</span>
|
|
|
|
|
|
<span class="o">></span> <span class="k">if</span> <span class="p">(</span> <span class="n">a</span> <span class="o">></span> <span class="mi">5</span> <span class="p">)</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="o">></span> <span class="o">></span> <span class="n">SEISCOMP_DEBUG</span><span class="p">(</span><span class="s">"A is greater than 5. Its current value is %d"</span><span class="p">,</span>
|
|
|
|
|
|
<span class="o">></span> <span class="o">></span> <span class="p">...............</span><span class="n">a</span><span class="p">);</span>
|
|
|
|
|
|
<span class="o">></span> <span class="k">return</span> <span class="n">a</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>C++ code is (or should be) written with the following code style:</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="cm">/***************************************************************************</span>
|
|
|
|
|
|
<span class="cm"> * Copyright (C) ... *</span>
|
|
|
|
|
|
<span class="cm"> * *</span>
|
|
|
|
|
|
<span class="cm"> * All rights reserved. *</span>
|
|
|
|
|
|
<span class="cm"> * Contact: <contact> *</span>
|
|
|
|
|
|
<span class="cm"> * *</span>
|
|
|
|
|
|
<span class="cm"> * Author: <name> *</span>
|
|
|
|
|
|
<span class="cm"> * Email: <email> *</span>
|
|
|
|
|
|
<span class="cm"> * *</span>
|
|
|
|
|
|
<span class="cm"> * GNU Affero General Public License Usage *</span>
|
|
|
|
|
|
<span class="cm"> * This file may be used under the terms of the GNU Affero *</span>
|
|
|
|
|
|
<span class="cm"> * Public License version 3.0 as published by the Free Software Foundation *</span>
|
|
|
|
|
|
<span class="cm"> * and appearing in the file LICENSE included in the packaging of this *</span>
|
|
|
|
|
|
<span class="cm"> * file. Please review the following information to ensure the GNU Affero *</span>
|
|
|
|
|
|
<span class="cm"> * Public License version 3.0 requirements will be met: *</span>
|
|
|
|
|
|
<span class="cm"> * https://www.gnu.org/licenses/agpl-3.0.html. *</span>
|
|
|
|
|
|
<span class="cm"> * *</span>
|
|
|
|
|
|
<span class="cm"> * Other Usage *</span>
|
|
|
|
|
|
<span class="cm"> * Alternatively, this file may be used in accordance with the terms and *</span>
|
|
|
|
|
|
<span class="cm"> * conditions contained in a signed written agreement between you and *</span>
|
|
|
|
|
|
<span class="cm"> * gempa GmbH. *</span>
|
|
|
|
|
|
<span class="cm"> ***************************************************************************/</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="cp">#ifndef NAMESPACE_LIB_FILENAME_H</span>
|
|
|
|
|
|
<span class="cp">#define NAMESPACE_LIB_FILENAME_H</span>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<span class="cp">#include</span> <span class="cpf"><math.h></span><span class="cp"></span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="k">class</span> <span class="nc">Complex</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">public</span><span class="o">:</span>
|
|
|
|
|
|
<span class="n">Complex</span><span class="p">(</span><span class="kt">double</span> <span class="n">re</span><span class="p">,</span> <span class="kt">double</span> <span class="n">im</span><span class="p">)</span>
|
|
|
|
|
|
<span class="o">:</span> <span class="n">_re</span><span class="p">(</span><span class="n">re</span><span class="p">),</span> <span class="n">_im</span><span class="p">(</span><span class="n">im</span><span class="p">)</span> <span class="p">{}</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="kt">double</span> <span class="n">modulus</span><span class="p">()</span> <span class="k">const</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">return</span> <span class="n">sqrt</span><span class="p">(</span><span class="n">_re</span> <span class="o">*</span> <span class="n">_re</span> <span class="o">+</span> <span class="n">_im</span> <span class="o">*</span> <span class="n">_im</span><span class="p">);</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="o"><</span><span class="k">template</span> <span class="k">typename</span> <span class="n">T</span><span class="o">></span>
|
|
|
|
|
|
<span class="kt">void</span> <span class="n">set</span><span class="p">(</span><span class="n">T</span> <span class="n">r</span><span class="p">,</span> <span class="n">T</span> <span class="n">i</span><span class="p">)</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="n">_re</span> <span class="o">=</span> <span class="n">r</span><span class="p">;</span>
|
|
|
|
|
|
<span class="n">_im</span> <span class="o">=</span> <span class="n">i</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="k">private</span><span class="o">:</span>
|
|
|
|
|
|
<span class="kt">double</span> <span class="n">_re</span><span class="p">;</span>
|
|
|
|
|
|
<span class="kt">double</span> <span class="n">_im</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">};</span>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<span class="kt">void</span> <span class="nf">bar</span><span class="p">(</span><span class="kt">int</span> <span class="n">i</span><span class="p">)</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">static</span> <span class="kt">int</span> <span class="n">counter</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span>
|
|
|
|
|
|
<span class="n">counter</span> <span class="o">+=</span> <span class="n">i</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<span class="k">namespace</span> <span class="n">Foo</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">namespace</span> <span class="n">Bar</span> <span class="p">{</span>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<span class="kt">void</span> <span class="n">foo</span><span class="p">(</span><span class="kt">int</span> <span class="n">a</span><span class="p">,</span> <span class="kt">int</span> <span class="n">b</span><span class="p">)</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">for</span> <span class="p">(</span> <span class="kt">int</span> <span class="n">i</span> <span class="o">=</span> <span class="mi">0</span><span class="p">;</span> <span class="n">i</span> <span class="o"><</span> <span class="n">a</span><span class="p">;</span> <span class="o">++</span><span class="n">i</span> <span class="p">)</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">if</span> <span class="p">(</span> <span class="n">i</span> <span class="o"><</span> <span class="n">b</span> <span class="p">)</span>
|
|
|
|
|
|
<span class="n">bar</span><span class="p">(</span><span class="n">i</span><span class="p">);</span>
|
|
|
|
|
|
<span class="k">else</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="n">bar</span><span class="p">(</span><span class="n">i</span><span class="p">);</span>
|
|
|
|
|
|
<span class="n">bar</span><span class="p">(</span><span class="n">b</span><span class="p">);</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<span class="p">}</span> <span class="c1">// namespace Bar</span>
|
|
|
|
|
|
<span class="p">}</span> <span class="c1">// namespace Foo</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="cp">#endif</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="file-layout">
|
|
|
|
|
|
<h3>File layout<a class="headerlink" href="#file-layout" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<ul>
|
|
|
|
|
|
<li><p>See above header example</p></li>
|
|
|
|
|
|
<li><p><strong>Trailing newline</strong>: use a newline at the end of each source file.</p></li>
|
|
|
|
|
|
<li><p><strong>Include guards</strong>: Use include guards in your header files instead of #pragma once:</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="cp">#ifndef NAMESPACE_LIB_FILENAME_H</span>
|
|
|
|
|
|
<span class="cp">#define NAMESPACE_LIB_FILENAME_H</span>
|
|
|
|
|
|
<span class="p">...</span>
|
|
|
|
|
|
<span class="cp">#endif</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="name-layout">
|
|
|
|
|
|
<h3>Name layout<a class="headerlink" href="#name-layout" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>Use descriptive names and camel capping. That means the name of the element
|
|
|
|
|
|
starts with the case given in the following table. Every concatenated word
|
|
|
|
|
|
starts with an uppercase letter (e.g. myDescriptiveElementName).</p>
|
|
|
|
|
|
<p>For straight enumerations where values start with 0 a quantity name should be
|
|
|
|
|
|
defined that describes the upper bound for all valid enumeration values. Its
|
|
|
|
|
|
name should be prepended by two letters describing the enumeration name and an
|
|
|
|
|
|
underscore.</p>
|
|
|
|
|
|
<p>Look at the class example above for guidance.</p>
|
|
|
|
|
|
<table class="docutils align-default">
|
|
|
|
|
|
<colgroup>
|
|
|
|
|
|
<col style="width: 33%" />
|
|
|
|
|
|
<col style="width: 25%" />
|
|
|
|
|
|
<col style="width: 43%" />
|
|
|
|
|
|
</colgroup>
|
|
|
|
|
|
<thead>
|
|
|
|
|
|
<tr class="row-odd"><th class="head"><p>Type</p></th>
|
|
|
|
|
|
<th class="head"><p>Case of first letter</p></th>
|
|
|
|
|
|
<th class="head"><p>Comment</p></th>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
</thead>
|
|
|
|
|
|
<tbody>
|
|
|
|
|
|
<tr class="row-even"><td><p>variable</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-odd"><td><p>function</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-even"><td><p>structure</p></td>
|
|
|
|
|
|
<td><p>uppercase</p></td>
|
|
|
|
|
|
<td></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-odd"><td><p>class</p></td>
|
|
|
|
|
|
<td><p>uppercase</p></td>
|
|
|
|
|
|
<td></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-even"><td colspan="3"><p>member variables:</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-odd"><td><p>- public</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td><p>starts without underscore</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-even"><td><p>- protected</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td><p>starts with underscore</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-odd"><td><p>- private</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td><p>starts with underscore</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-even"><td><p>methods</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td><p>no</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-odd"><td><p>static methods</p></td>
|
|
|
|
|
|
<td><p>uppercase</p></td>
|
|
|
|
|
|
<td><p>no</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-even"><td><p>inline methods and
|
|
|
|
|
|
templates</p></td>
|
|
|
|
|
|
<td><p>lowercase</p></td>
|
|
|
|
|
|
<td><p>sourced out into separate .ipp file
|
|
|
|
|
|
with same name as the header file</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-odd"><td><p>enumeration</p></td>
|
|
|
|
|
|
<td><p>uppercase</p></td>
|
|
|
|
|
|
<td><p>elements are written all uppercase</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
<tr class="row-even"><td><p>documentation and
|
|
|
|
|
|
comments</p></td>
|
|
|
|
|
|
<td><ul class="simple">
|
|
|
|
|
|
<li></li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</td>
|
|
|
|
|
|
<td><p>use Doxygen</p></td>
|
|
|
|
|
|
</tr>
|
|
|
|
|
|
</tbody>
|
|
|
|
|
|
</table>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="file-naming">
|
|
|
|
|
|
<h3>File naming<a class="headerlink" href="#file-naming" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>All source and header files are named with lowercase letters. The suffix of a
|
|
|
|
|
|
source file is “.cpp” while for a header file it is “.h”. The name of files
|
|
|
|
|
|
that contain a class has to correspond with the class name. For other files,
|
|
|
|
|
|
a descriptive name has to be provided (e.g. protocol.h instead of pro.h).</p>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="programming-guidelines">
|
|
|
|
|
|
<h2>Programming Guidelines<a class="headerlink" href="#programming-guidelines" title="Permalink to this headline">¶</a></h2>
|
|
|
|
|
|
<div class="section" id="return-values">
|
|
|
|
|
|
<h3>Return values<a class="headerlink" href="#return-values" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>While designing methods or functions these rules about return values should be kept in mind:</p>
|
|
|
|
|
|
<ul>
|
|
|
|
|
|
<li><p>Functions returning an int or related types as status: 0 means success;
|
|
|
|
|
|
everything else is an error <a class="footnote-reference brackets" href="#id6" id="id2">1</a></p></li>
|
|
|
|
|
|
<li><p>Functions returning a pointer:
|
|
|
|
|
|
0 (or <code class="code docutils literal notranslate"><span class="pre">nullptr</span></code>) means an error and of course an
|
|
|
|
|
|
invalid pointer <a class="footnote-reference brackets" href="#id6" id="id3">1</a></p></li>
|
|
|
|
|
|
<li><p>Functions returning a class object can throw an exception in case of an error.
|
|
|
|
|
|
This is not obligatory and should be used with care.</p>
|
|
|
|
|
|
<p><strong>Example</strong>: std::string myMethod();</p>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="exception-specifications">
|
|
|
|
|
|
<h3>Exception specifications<a class="headerlink" href="#exception-specifications" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>According to <a class="footnote-reference brackets" href="#id7" id="id4">2</a> dynamic exception specifications are considered or proposed
|
|
|
|
|
|
as deprecated feature and not recommended <a class="footnote-reference brackets" href="#id8" id="id5">3</a>. Don’t use them in declaring a function prototype.</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="c1">// Don't use that</span>
|
|
|
|
|
|
<span class="kt">int</span> <span class="nf">foo</span><span class="p">()</span> <span class="k">throw</span><span class="p">(</span><span class="n">ValueException</span><span class="p">);</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="c1">// Just declare it without an exception specification</span>
|
|
|
|
|
|
<span class="kt">int</span> <span class="nf">foo</span><span class="p">();</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="null-pointer">
|
|
|
|
|
|
<h3>Null pointer<a class="headerlink" href="#null-pointer" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>Use either 0 or the <code class="code docutils literal notranslate"><span class="pre">nullptr</span></code> keyword of C++11.
|
|
|
|
|
|
Check a null pointer with implicit boolean conversion.</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span> <span class="o">!</span><span class="n">ptr</span> <span class="p">)</span>
|
|
|
|
|
|
<span class="n">do_something</span><span class="p">();</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>rather than</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span> <span class="n">ptr</span> <span class="o">==</span> <span class="mi">0</span> <span class="p">)</span>
|
|
|
|
|
|
<span class="n">do_something</span><span class="p">();</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>or</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="p">(</span> <span class="n">ptr</span> <span class="o">==</span> <span class="nb">NULL</span> <span class="p">)</span>
|
|
|
|
|
|
<span class="n">do_something</span><span class="p">();</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="section" id="virtual-functions">
|
|
|
|
|
|
<h3>Virtual Functions<a class="headerlink" href="#virtual-functions" title="Permalink to this headline">¶</a></h3>
|
|
|
|
|
|
<p>Virtual functions are a fundamental concept of polymorphic classes. Virtual
|
|
|
|
|
|
functions will be overwritten in derived classes to implement specific
|
|
|
|
|
|
behaviour. It can happen that the signature of the virtual function in the
|
|
|
|
|
|
base class changes but derived classes do not follow this change.</p>
|
|
|
|
|
|
<p>This causes in erroneous behaviour as the derived virtual function will not
|
|
|
|
|
|
be called as desired. What is even worse is that this mismatch of signatures
|
|
|
|
|
|
is hard to find and to debug.</p>
|
|
|
|
|
|
<p>Fortunately C++11 introduces the long awaited override keyword which declares
|
|
|
|
|
|
that a virtual function of a derived class intends to override the virtual
|
|
|
|
|
|
function with the same name of the base class. If both signatures do not match,
|
|
|
|
|
|
the compiler will throw an error.</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Base</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">virtual</span> <span class="kt">void</span> <span class="n">print</span><span class="p">()</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="n">cout</span> <span class="o"><<</span> <span class="s">"Base class"</span> <span class="o"><<</span> <span class="n">endl</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
|
|
|
|
|
|
<span class="k">class</span> <span class="nc">Derived</span> <span class="o">:</span> <span class="k">public</span> <span class="n">Base</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">virtual</span> <span class="kt">void</span> <span class="n">print</span><span class="p">()</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="n">cout</span> <span class="o"><<</span> <span class="s">"Derived class"</span> <span class="o"><<</span> <span class="n">endl</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>If we change the signature of print to take an additional parameter then
|
|
|
|
|
|
the derived method will not be called anymore.</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Base</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="k">virtual</span> <span class="kt">void</span> <span class="n">print</span><span class="p">(</span><span class="n">ostream</span> <span class="o">&</span><span class="n">os</span><span class="p">)</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="n">os</span> <span class="o"><<</span> <span class="s">"Base class"</span> <span class="o"><<</span> <span class="n">endl</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>Adding the override keyword will force the compiler to check both signatures
|
|
|
|
|
|
for equality.</p>
|
|
|
|
|
|
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Derived</span> <span class="o">:</span> <span class="k">public</span> <span class="n">Base</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="kt">void</span> <span class="n">print</span><span class="p">()</span> <span class="k">override</span> <span class="p">{</span>
|
|
|
|
|
|
<span class="n">os</span> <span class="o"><<</span> <span class="s">"Derived class"</span> <span class="o"><<</span> <span class="n">endl</span><span class="p">;</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
<span class="p">}</span>
|
|
|
|
|
|
</pre></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<p>This code above will throw an error during compilation and one has to adapt
|
|
|
|
|
|
the signature of the function.</p>
|
|
|
|
|
|
<p>Use the override keyword whenever you implement a virtual function in derived
|
|
|
|
|
|
classes.</p>
|
|
|
|
|
|
<dl class="footnote brackets">
|
|
|
|
|
|
<dt class="label" id="id6"><span class="brackets">1</span><span class="fn-backref">(<a href="#id2">1</a>,<a href="#id3">2</a>)</span></dt>
|
|
|
|
|
|
<dd><p><a class="reference external" href="http://www.stroustrup.com/bs_faq2.html#null">http://www.stroustrup.com/bs_faq2.html#null</a></p>
|
|
|
|
|
|
</dd>
|
|
|
|
|
|
<dt class="label" id="id7"><span class="brackets"><a class="fn-backref" href="#id4">2</a></span></dt>
|
|
|
|
|
|
<dd><p><a class="reference external" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3051.html">http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3051.html</a></p>
|
|
|
|
|
|
</dd>
|
|
|
|
|
|
<dt class="label" id="id8"><span class="brackets"><a class="fn-backref" href="#id5">3</a></span></dt>
|
|
|
|
|
|
<dd><p><a class="reference external" href="http://www.gotw.ca/publications/mill22.htm">http://www.gotw.ca/publications/mill22.htm</a></p>
|
|
|
|
|
|
</dd>
|
|
|
|
|
|
</dl>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<div id="anchors-bottom"></div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
|
|
<div class="sidebar" role="navigation" aria-label="main navigation">
|
|
|
|
|
|
<div id="anchors-top"></div>
|
|
|
|
|
|
<div id="anchors" class="content">
|
|
|
|
|
|
<div id="searchbox" style="display: none" role="search">
|
|
|
|
|
|
<h3 id="searchlabel">Quick search</h3>
|
|
|
|
|
|
<div class="searchformwrapper">
|
|
|
|
|
|
<form class="search" action="../search.html" method="get">
|
|
|
|
|
|
<input type="text" name="q" aria-labelledby="searchlabel" />
|
|
|
|
|
|
<input type="submit" value="Go" />
|
|
|
|
|
|
</form>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<script>$('#searchbox').show(0);</script>
|
|
|
|
|
|
<h3><a href="../index.html">Table of Contents</a></h3>
|
|
|
|
|
|
<ul>
|
|
|
|
|
|
<li><a class="reference internal" href="#">Coding Conventions</a><ul>
|
|
|
|
|
|
<li><a class="reference internal" href="#code-style">Code Style</a><ul>
|
|
|
|
|
|
<li><a class="reference internal" href="#formatting">Formatting</a></li>
|
|
|
|
|
|
<li><a class="reference internal" href="#file-layout">File layout</a></li>
|
|
|
|
|
|
<li><a class="reference internal" href="#name-layout">Name layout</a></li>
|
|
|
|
|
|
<li><a class="reference internal" href="#file-naming">File naming</a></li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
<li><a class="reference internal" href="#programming-guidelines">Programming Guidelines</a><ul>
|
|
|
|
|
|
<li><a class="reference internal" href="#return-values">Return values</a></li>
|
|
|
|
|
|
<li><a class="reference internal" href="#exception-specifications">Exception specifications</a></li>
|
|
|
|
|
|
<li><a class="reference internal" href="#null-pointer">Null pointer</a></li>
|
|
|
|
|
|
<li><a class="reference internal" href="#virtual-functions">Virtual Functions</a></li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
|
|
|
|
|
|
<h4>Previous topic</h4>
|
|
|
|
|
|
<p class="topless"><a href="style-guide.html"
|
|
|
|
|
|
title="previous chapter">Style Guide for Documentation</a></p>
|
|
|
|
|
|
<h4>Next topic</h4>
|
|
|
|
|
|
<p class="topless"><a href="tests.html"
|
|
|
|
|
|
title="next chapter">Unit Testing</a></p>
|
|
|
|
|
|
<div role="note" aria-label="source link">
|
|
|
|
|
|
<h3>This Page</h3>
|
|
|
|
|
|
<ul class="this-page-menu">
|
|
|
|
|
|
<li><a href="../_sources/base/coding-conventions.rst.txt"
|
|
|
|
|
|
rel="nofollow">Show Source</a></li>
|
|
|
|
|
|
</ul>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="footer">
|
|
|
|
|
|
<div class="container">
|
|
|
|
|
|
<div class="horizontal layout content">
|
|
|
|
|
|
<a class="fade-in" href="https://www.gempa.de" target="_blank">
|
|
|
|
|
|
<img class="brand" src="../_static/brands/gempa.svg"/>
|
|
|
|
|
|
</a>
|
|
|
|
|
|
<div class="stretched align-center fitted content">
|
|
|
|
|
|
<div>
|
|
|
|
|
|
Version <b>5.3.0</b> Release
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<div class="copyright">
|
|
|
|
|
|
Copyright © gempa GmbH, GFZ Potsdam.
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<a class="fade-in" href="https://www.gfz-potsdam.de" target="_blank">
|
|
|
|
|
|
<img class="brand" src="../_static/brands/gfz.svg"/>
|
|
|
|
|
|
</a>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
</body>
|
|
|
|
|
|
</html>
|
