connecting to a remote (as in slime-connect) cmucl lisp with the *communication-style* set to :sigio. a thread signals an error and i get an sldb debugger in emacs. however none of the restarts actually do anything. all i get is a message in the minibuffer "Restart returned: nil" and i'm left in the debugger. the only restart which causes a noticable change is the sldb-abort restart, which gets me out of the debugger but leave the thread waiting for input. setting the *communication-style* to :spawn fixs the issue.