A named pipe stream.
A non-negative real number, or
A string, or
A function designator, or
wait-for-connection waits until it succeeds to establish a connection for the stream stream, or timeout seconds passed or wait-function returns non-nil, and returns a value indicating whether the connection is established successfully.
stream must be a stream of the right type. Currently the only supported stream is a named pipe stream (the result of open-named-pipe-stream).
wait-reason, if non-nil, needs to be a string specifying the wait reason. It has the same semantics as the wait-reason argument of process-wait.
wait-function has the same limitations as the wait-function of process-wait.
LispWorks User Guide and Reference Manual - 20 Sep 2017