How to start a application in a specific orientation

By default, applications are started in the current orientation of the device screen. In order to force an application to be started in landscape mode or portrait mode, a corresponding flag needs to be passed to the BaseConstructL() function in AknAppUi::ConstructL():

void CMyAppUi::ConstructL()
   {
   BaseConstructL( EAknEnableSkin | EAppOrientationLandscape );    // start in landscape mode
   //BaseConstructL( EAknEnableSkin | EAppOrientationPortrait );    // start in Portrait mode
   ...
   }

Note: enums Passed BaseConstructL() are different from enums that are passed to SetOrientationL().