    The given NAMEs are marked readonly and the values of these NAMEs may
    not be changed by subsequent assignment.  If the -f option is given,
    then functions corresponding to the NAMEs are so marked.  If no
    arguments are given, or if `-p' is given, a list of all readonly names
    is printed.  The `-a' option means to treat each NAME as
    an array variable.  An argument of `--' disables further option
    processing.
