Opens a stream for reading.
- iOS 2.0+
- macOS 10.1+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
- Core Foundation
The stream to open.
stream was successfully opened,
FALSE otherwise. If
stream is not in the
CFStream state, this function returns
Opening a stream causes it to reserve all the system resources it requires. If the stream can open in the background without blocking, this function always returns
true. To learn when a background open operation completes, you can either schedule the stream into a run loop with
CFRead and wait for the stream’s client (set with
CFRead) to be notified or you can poll the stream using
CFRead, waiting for a status of
You do not need to wait until a stream has finished opening in the background before calling the
CFRead function. The read operation will simply block until the open has completed.