func withUnsafePointer<T, Result>(inout: T, _: UnsafePointer<T> throws -> Result) Invokes body with an UnsafePointer to arg and returns the result. Useful for calling Objective-C APIs that take "in/out" parameters (and default-constructible "out" parameters) by pointer. Declaration func withUnsafePointer<T, Result>(inout arg: T, @noescape _ body: UnsafePointer<T> throws -> Result) rethrows -> Result