SYNOPSIS
        int referencep(mixed arg)

DESCRIPTION
        returns true if arg was passed by reference to the current
        function, instead of the usual call-by-value.

        Note that arg has to be passed by reference to the efun,
        a.g. referencep(&x).

SEE ALSO
        references(LPC) clonep(E), closurep(E), floatp(E),
        mappingp(E), objectp(E), intp(E), pointerp(E), stringp(E),
        symbolp(E), structp(E)