wxApp destructor is virtual [ patch 1283503 ]

[wxWidgets.git] / docs / latex / wx / tapp.tex

diff --git a/docs/latex/wx/tapp.tex b/docs/latex/wx/tapp.tex
index 563b3d085bc3ca3a4ab609b0996692da79ac6df4..9af797b27db6bfd1baa042f720dc1d35d515453e 100644 (file)
--- a/docs/latex/wx/tapp.tex
+++ b/docs/latex/wx/tapp.tex
@@ -2,13 +2,13 @@
 
 Classes: \helpref{wxApp}{wxapp}
 
-A wxWindows application does not have a {\it main} procedure; the equivalent is the
+A wxWidgets application does not have a {\it main} procedure; the equivalent is the
 \rtfsp\helpref{OnInit}{wxapponinit} member defined for a class derived from wxApp.\rtfsp
 \rtfsp{\it OnInit} will usually create a top window as a bare minimum.
 
-Unlike in earlier versions of wxWindows, OnInit does not return a frame. Instead it
-returns a boolean value which indicates whether processing should continue (TRUE) or not (FALSE).
-You call \helpref{wxApp::SetTopWindow}{wxappsettopwindow} to let wxWindows know
+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 \helpref{wxApp::SetTopWindow}{wxappsettopwindow} to let wxWidgets know
 about the top window.
 
 Note that the program's command line arguments, represented by {\it argc} 
@@ -22,7 +22,8 @@ is to explicitly delete child frames in the top-level frame's \helpref{wxCloseEv
 handler.
 
 In emergencies the \helpref{wxExit}{wxexit} function can be called to kill the
-application.
+application however normally the application shuts down automatically, 
+\helpref{see below}{wxappshutdownoverview}.
 
 An example of defining an application follows:
 
@@ -39,27 +40,43 @@ bool DerivedApp::OnInit()
 {
   wxFrame *the_frame = new wxFrame(NULL, ID_MYFRAME, argv[0]);
   ...
-  the_frame->Show(TRUE);
+  the_frame->Show(true);
   SetTopWindow(the_frame);
 
-  return TRUE;
+  return true;
 }
 \end{verbatim}
 
-Note the use of IMPLEMENT\_APP(appClass), which allows wxWindows to dynamically create an instance of the application object
-at the appropriate point in wxWindows initialization. Previous versions of wxWindows used
+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.
+a reference to the application object. Otherwise you can only use the global 
+\texttt{wxTheApp} pointer which is of type \texttt{wxApp *}.
 
-\subsection{Application shutdown}
 
-\helpref{OnExit}{wxapponexit} is called when the application exits but {\it before}
-wxWindows cleans its internal structures. Your should delete all wxWindows object that
-your created by the time OnExit finishes. In particular, do {\bf not} destroy them
+\subsection{Application shutdown}\label{wxappshutdownoverview}
+
+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 \helpref{Close()}{wxwindowclose} in response to the {\tt "Exit"} menu
+command if your program has a single top level window. If this behaviour is not
+desirable \helpref{wxApp::SetExitOnFrameDelete}{wxappsetexitonframedelete} can
+be called to change it. Note that starting from wxWidgets 2.3.3 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 
+\helpref{wxApp::OnInit}{wxapponinit} 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 \helpref{OnExit}{wxapponexit} 
+which is called when the application exits but {\it before} wxWidgets cleans up
+its internal structures. You should delete all wxWidgets object that you
+created by the time OnExit finishes. In particular, do {\bf not} destroy them
 from application class' destructor!
 
 For example, this code may crash:
@@ -75,7 +92,7 @@ class MyApp : public wxApp
 
 The reason for that is that {\tt m\_helpCtrl} is a member object and is 
 thus destroyed from MyApp destructor. But MyApp object is deleted after 
-wxWindows structures that wxCHMHelpController depends on were 
+wxWidgets structures that wxCHMHelpController depends on were 
 uninitialized! The solution is to destroy HelpCtrl in {\it OnExit}:
 
 \begin{verbatim}