You can pass a reference to a something that the task should update as one of its arguments (e.g. a pointer to a place in memory big enough for a pointer that s

You can pass a reference to a something that the task should update as one of its arguments (e.g. a pointer to a place in memory big enough for a pointer that starts out as null). Then wait for the task. Then check what it left you at the reference. It's the world's most boring channel.