Starting application in full screen

[wysota]

How to start application in full screen.

showFullScreen()

How can I add my application in start up in linux.

It depends what you mean. In KDE you can add it to your Autostart directory.

How to diable title bar button (programtically).

Which button exactly?

[safknw]

Close and minimize buttons.

[wysota]

You have to set (or clear) appropriate window flags in the window constructor. To get rid of the "minimise" button, you should probably clear the Qt::WindowMinimizeButtonHint flag. I didn't find one for the close button (which doesn't mean there is no flag for that). Alternatively use a window type which doesn't have those buttons (for example using Qt::FramelessWindowHint).