

   WWaarrnniinngg MMeessssaaggeess

        warning(message)

   DDeessccrriippttiioonn::

        `warning' generates a warning message that corresponds
        to its argument. The result depends on the value of
        `options("warn")'.  If `warn' is negative warnings are
        ignored; if it is zero they are stored and printed
        after the top-level function has completed; if it is
        one they are printed as they occur and if it is 2 (or
        larger) warnings are turned into errors.  If `warn' is
        zero a top-level variable `last.warning' is created. It
        contains the warnings which can be printed via a call
        to `warnings'.

   EExxaammpplleess::

        if(eigenval < 1.e-7) warning("system near singular")

        if(eigenval < 1.e-7) warning("system near singular")

