remarks about systems that don't support fractional seconds.
The argument @var{seconds} need not be an integer. If it is a floating
point number, this function waits for a fractional number of seconds.
-Some systems support only a whole number of seconds; on these systems,
-@var{seconds} is rounded down.
-
-Not all operating systems support waiting periods other than multiples
-of a second; on those that do not, you get an error if you specify
-nonzero @var{millisec}.
@c Emacs 22.1 feature
If @var{process} is a process, and the argument @var{just-this-one} is