+@page overview_app wxApp Overview
+
+Classes: wxApp
+
+@li @ref overview_app_intro
+@li @ref overview_app_shutdown
+
+
+<hr>
+
+
+@section overview_app_intro Introduction
+
+A wxWidgets application does not have a @e main procedure; the equivalent is
+the wxApp::OnInit member defined for a class derived from wxApp.
+
+@e OnInit will usually create a top window as a bare minimum. Unlike in earlier
+versions of wxWidgets, OnInit does not return a frame. Instead it returns a
+boolean value which indicates whether processing should continue (@true) or not
+(@false). You call wxApp::SetTopWindow to let wxWidgets know about the top
+window.
+
+Note that the program's command line arguments, represented by @e argc and
+@e argv, are available from within wxApp member functions.
+
+An application closes by destroying all windows. Because all frames must be
+destroyed for the application to exit, it is advisable to use parent frames
+wherever possible when creating new frames, so that deleting the top level
+frame will automatically delete child frames. The alternative is to explicitly
+delete child frames in the top-level frame's wxCloseEvent handler.
+
+In emergencies the wxExit function can be called to kill the application
+however normally the application shuts down automatically, see
+@ref overview_app_shutdown.
+
+An example of defining an application follows:
+
+@code
+class DerivedApp : public wxApp
+{
+public:
+ virtual bool OnInit();
+};
+
+IMPLEMENT_APP(DerivedApp)
+
+bool DerivedApp::OnInit()
+{
+ wxFrame *the_frame = new wxFrame(NULL, ID_MYFRAME, argv[0]);
+ ...
+ the_frame->Show(true);
+ SetTopWindow(the_frame);
+
+ return true;
+}
+@endcode
+
+Note the use of IMPLEMENT_APP(appClass), which allows wxWidgets to dynamically
+create an instance of the application object at the appropriate point in
+wxWidgets initialization. Previous versions of wxWidgets used to rely on the
+creation of a global application object, but this is no longer recommended,
+because required global initialization may not have been performed at
+application object construction time.
+
+You can also use DECLARE_APP(appClass) in a header file to declare the wxGetApp
+function which returns a reference to the application object. Otherwise you can
+only use the global @c wxTheApp pointer which is of type @c wxApp*.
+
+
+@section overview_app_shutdown Application Shutdown
+
+The application normally shuts down when the last of its top level windows is
+closed. This is normally the expected behaviour and means that it is enough to
+call wxWindow::Close() in response to the "Exit" menu command if your program
+has a single top level window. If this behaviour is not desirable
+wxApp::SetExitOnFrameDelete can be called to change it.
+
+Note that such logic doesn't apply for the windows shown before the program
+enters the main loop: in other words, you can safely show a dialog from
+wxApp::OnInit and not be afraid that your application terminates when this
+dialog -- which is the last top level window for the moment -- is closed.
+
+Another aspect of the application shutdown is wxApp::OnExit which is called
+when the application exits but @e before wxWidgets cleans up its internal
+structures. You should delete all wxWidgets object that you created by the time
+OnExit finishes.
+
+In particular, do @b not destroy them from application class' destructor! For
+example, this code may crash:
+
+@code
+class MyApp : public wxApp
+{
+public:
+ wxCHMHelpController m_helpCtrl;
+ ...
+};
+@endcode
+
+The reason for that is that @c m_helpCtrl is a member object and is thus
+destroyed from MyApp destructor. But MyApp object is deleted after wxWidgets
+structures that wxCHMHelpController depends on were uninitialized! The solution
+is to destroy HelpCtrl in @e OnExit:
+
+@code
+class MyApp : public wxApp
+{
+public:
+ wxCHMHelpController *m_helpCtrl;
+ ...
+};
+
+bool MyApp::OnInit()
+{
+ ...
+ m_helpCtrl = new wxCHMHelpController;
+ ...
+}
+
+int MyApp::OnExit()
+{
+ delete m_helpCtrl;
+ return 0;
+}
+@endcode
+
+*/
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