private function valFromConf(dr_numdoc,dr_tipdoc,dr_anndoc,dr_riga,cod_cnf)
    sql = "SELECT cnfv_val FROM cnf_valconf WHERE "
    sql = sql & " cnfv_numdoc       = " & sy_cvn(dr_numdoc)
    sql = sql & " AND cnfv_tipdoc   = " & sy_cvs(dr_tipdoc)
    sql = sql & " AND cnfv_anndoc   = " & sy_cvn(dr_anndoc)
    sql = sql & " AND cnfv_dcriga   = " & sy_cvn(dr_riga)
    sql = sql & " AND cnfv_cnfprg   = " & sy_cvn(cod_cnf)
    set rsc = conn.execute(sql)
    if not rsc.eof then
        valFromConf = rsc("cnfv_val")
    else
        valFromConf = ""
    end if
end function