How to take a screen shot of an app (within an app)? (iPhone)

So what if I want to make an app where you can take a screen shot within the app itself. How would I do that? So for example the users cl开发者_Go百科ick a UIButton and it takes a picture of the screen.

There is an undocumented, but SDK allowed, function UIGetScreenImage(). It returns a CGImage that you are responsible for releasing yourself.

Are you just trying to take screenshots? Or is there a reason you need to take a screenshot in the application itself?

Because on the iphone you can hit the power button and home button at the same time to take a screenshot (which is saved the to the camera roll).