Returns the frequency of updates to the system time.
- iOS 4.0+
- macOS 10.4+
- tvOS 9.0+
- watchOS 2.0+
- Core Video
The current host frequency.
In macOS, the host time bases for Core Video and CoreAudio are identical—both are based on the
mach function—so the values returned from either API can be used interchangeably.