Coding Conventions

Revision as of 18:50, 22 February 2013 by Marcus.hanwell (talk | contribs) (Added some notes on coding conventions)
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C++ Features

  • Don't use exceptions
  • Prefer solutions from the Qt library over Boost/others in Qt dependent code
    • In Avogadro use the C++11 features where necessary, they fall back to Boost on older compilers
    • Avogadro offers AVO_OVERRIDE and AVO_FINAL (defines for new C++11 override and final)
  • Minimize dependencies on third party libraries, think carefully before adding more
  • Use templates where they make sense
  • Submit proposed topics to Gerrit
    • Monitor the CDash@Home builds and nightly builds once merged to ensure support in all supported compilers

Including Headers

  • In public headers, always use this form to include project headers: #include <avogadro/core/something.h>
  • Prefer declaration of types in public headers over including headers for the type
namespace Avogadro {
class MyClass;
  • In source files include specialized headers first, then dependency headers, then generic headers
 #include "myapiheader.h" // Our header
 #include <avogadro/core/molecule.h> // Avogadro header from a different module
 #include <QtCore/QString> // Qt header
 #include <vector> // STL

Export Macro Headers

  • If you need to include the export header for the module do it as the first include
 #include "avogadrorenderingexport.h"

Private Headers

  • Private headers are denoted by _p.h endings, and should not be included in public headers

Qt Headers

  • Use the Qt module and camel-cased header
  • Never include Qt module headers such as QtGui, instead include the header for the class being used
 #include <QtGui> // WRONG (module header)!
 #include <QtGui/QDialog> // Correct


  • Open Chemistry code is namespaced
  • Avogadro uses nested namespaces
    • Everything is inside the Avogadro namespace
    • Code in the core module is in the Avogadro::Core namespace
  • MoleQueue and MongoChem use a namespace to contain most code
  • Don't overspecify, i.e. code in the Avogadro namespace doesn't need to use Avogadro::
    • Qt signals and slots are one exception where MOC often needs a little help
  • Never use using inside a public header
    • Only pull in specific symbols in source files, i.e. using Avogadro::Core::Molecule;


  • Avoid C-style casts, prefer C++ (static_cast, dynamic_cast, const_cast, reinterpret_cast)
  • For Qt classes, and Qt derived classes prefer qobject_cast over dynamic_cast


  • Prefer enums to define constants over static const int or defines
  • Prefer verbose argument names in headers
    • Most IDEs show the argument names in their autocompletion
    • It looks better in the generated documentation
    • Poor style making people guess what an argument is for
  • Avoid abbreviations, as they are often ambiguous and we can afford the extra bytes