Mac SDK: using latest SDK but ensuring backwards compatibility with earlier deployment target

Question

As always when Apple updates OS X, the latest XCode 4.4 dumps the older (10.6) SDK and I find myself needing to use the 10.7 SDK (or 10.8 I suppose) and setting my deploymen

Answer 1

Since Xcode 9 there is a build setting doing exactly this, turning on the warning -Wunguarded-availability and/or -Wunguarded-availability-new.

The former warns when an API newer than the deployment target is used. The latter only warns when an API introduced newer than macOS 10.13 or iOS 11 is used in a similar manner.

For an existing project, the former is off by default, and the latter is on by default.

This setting is called “unguarded availability” within Xcode’s build settings pane, and you can choose one of Yes, Yes for all versions, or No from the GUI.

For more details, see the WWDC17 session 411, “What's New in LLVM”, https://developer.apple.com/videos/play/wwdc2017/411/ .