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), bytesp(E), clonep(E), closurep(E), coroutinep(E),
        floatp(E), intp(E), lpctypep(E), lwobjectp(E), mappingp(E),
        objectp(E), pointerp(E), stringp(E), structp(E), symbolp(E)