[Lazarus] Serial communication??

[Paulo Costa]

On 04/10/2010 07:17, Bo Berglund wrote:

> Thanks for the suggestion! I have now installed the serial component
> of the suite on my Ubuntu Lazarus.
> As indicated there is an event for receiving the incoming data even
> though that event does not tell how many characters are actually
> available. So how do I know how many I can read in from the port?

You don't need to know. When you are in the OnRxData event if you call 
ReadData():

procedure TForm1.SdpoSerial1RxData(Sender: TObject);
var mess: string;
begin
   mess := SdpoSerial1.ReadData();
   ...
end;

It will return a string with all available bytes in the input buffer.

> But there is one strange thing about the way the component works:
> I can call the Open method for ttyS0 and there is no error even though
> the ttyS0 does not exist...
>
> I run my Ubuntu in a VMWare virtual machine and I had forgotten to add
> a serial port to its hardware so there is definitely no such port and
> yet there is no indication from the component that it has failed to
> open the port.
> How come?
>
> Should there not be an exception raised if the wanted port does not
> exist?

Yes. There is an exception that is raised when the open() call fails.

Paulo Costa