- may be scheduled before thread_create() returns. Use a
- semaphore or some other form of synchronization if you need to
- ensure ordering. */
-struct thread *
+ may be scheduled before thread_create() returns. It could
+ even exit before thread_create() returns. Use a semaphore or
+ some other form of synchronization if you need to ensure
+ ordering. Returns the thread identifier for the new thread,
+ or TID_ERROR if creation fails. */
+tid_t