function PrinterStatus : integer;
asm
mov ah, 2 // function 2 - returns status of port
mov dx, 0 // lpt1 = 0, lpt2 = 1 etc
int $17 // status in ah
mov al, ah
and eax, $FF // status now in eax with top 24 bits cleared
end;
const
PrinterCodes : array [0..7] of string =
('printer timed-out',
'unused',
'unused',
'I/O error',
'printer selected',
'out of paper',
'printer acknowedgment',
'printer not busy');
procedure TForm1.Button1Click(Sender: TObject);
var
L,P : integer;
begin
P := PrinterStatus;
//status of printer in P
ListBox1.Clear;
for L := 0 to 7do
if P and (1 shl L) <> 0 then
ListBox1.Items.Add (PrinterCodes [L]);
end;
这段代码你测试通过了吗? 缺纸和卡纸都是i/o错误 ? 我在这里测试, 我故意把纸
拿下来,他就报'out of paper', 没有报i/o出错.