discard_ilseq?

static VALUE
iconv_get_discard_ilseq(VALUE self)
{
#ifdef ICONV_GET_DISCARD_ILSEQ
    int dis = 0;
    iconv_ctl(self, ICONV_GET_DISCARD_ILSEQ, dis);
    if (dis) return Qtrue;
#else
    rb_notimplement();
#endif
    return Qfalse;
}