Opens a stream for reading.


Boolean CFReadStreamOpen(CFReadStreamRef stream);



The stream to open.

Return Value

TRUE if stream was successfully opened, FALSE otherwise. If stream is not in the kCFStreamStatusNotOpen state, this function returns FALSE.


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 CFReadStreamScheduleWithRunLoop and wait for the stream’s client (set with CFReadStreamSetClient) to be notified or you can poll the stream using CFReadStreamGetStatus, waiting for a status of kCFStreamStatusOpen or kCFStreamStatusError.

You do not need to wait until a stream has finished opening in the background before calling the CFReadStreamRead function. The read operation will simply block until the open has completed.

See Also

Opening and Closing a Read Stream


Closes a readable stream.