How to make my C++ opensource crossplatform application update itself? (any boost libs for that?)

I have an app. It is cross platform. It is not any way enterprise nor it has more than 500 users. So no one really wants to do anything bad to it. It has 3 packets available via http in some source repository manager like Google code for Mac OS Windows and Linux. I need my app to check for updates and download them and replace开发者_JAVA百科 current executables/files around, restart app. As for me - I see a way like to distribute 2 applications - one that checks for updates or runs currently existing executable and executable itself... I wonder what is really used and are there any boost libs for that or any other cross platform libs for such stuff?

I don't think there is a cross platform solution to automatic updates. They didn't seem to be able to find any here: How can I enable auto-updates in a Qt cross-platform application?