The package Qt_Ada.Application provides to the application the way to creates and executes instance of the QApplication class. It hides the complexity of the handling command line parameters and program's return code from the application. Application must use this package only if it doesn't use any classes from the QtGui module, otherwise it must use Qt_Ada.Core_Application package instead. Here is the package declaration:

package Qt_Ada.Application is

   procedure Initialize;
   --  Creates global instance of the QApplication class with options specified
   --  in the command line.

   procedure Execute;
   --  Executes main event loop until it don't be terminated. Set program
   --  exit code to the specified by the user exit code.

   procedure Finalize;
   --  Destroies global instance of the QApplication class.

end Qt_Ada.Application;

The procedure Initialize creates an instance of the QApplication class using program's command line parameters.

The procedure Execute run QApplication::exec operation and save returned code as program's return code.

The procedure Finalize destroies instance of the QApplication class.