UIVideoAtPathIsCompatibleWithSavedPhotosAlbum generates error implicit declaration of function, why?

In my project I am trying to save video to the iPhone after being taken by the camera.

When I call the method:

UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(path)

It reports the error:

Implicit dec开发者_运维问答laration of function 'UIVideoAtPathIsCompatibleWithSavedPhotosAlbum'

I've imported MobileCoreServices/UTCoreTypes.h

I was previously using this same code for saving camera pictures, and it worked fine.

In another class, in the same project, I am able to reference the UIKit method:

UIImagePNGRepresentation()

without any problems

So why does it give me this error?

After two hours of hunting I finally realized my project was set up for OS 3.0, and thus, the method was unavailable. It needed to be set for 3.1