(Delphi ActiveX) TCP Socket Send Byte and Receive Byte

Demonstrates the Chilkat Socket ReceiveByte and SendByte method.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
sock: TChilkatSocket;
useTls: Integer;
port: Integer;
maxWaitMs: Integer;
success: Integer;
treatAsUnsignedInt: Integer;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

sock := TChilkatSocket.Create(Self);

// --------------------------------------------------------------------
// This example uses the public TCP echo service at https://tcpbin.com/
// --------------------------------------------------------------------

useTls := 0;
port := 4242;
maxWaitMs := 5000;
success := sock.Connect('tcpbin.com',port,useTls,maxWaitMs);
if (success = 0) then
  begin
    Memo1.Lines.Add(sock.LastErrorText);
    Exit;
  end;

// Wait a max of 2 seconds for a response..
sock.MaxReadIdleMs := 2000;

// Send a byte.
sock.SendByte(96);

// The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
sock.SendByte(10);

// The echo server will echo back whatever is sent to it.
// We should be able to read the same byte back..
// After successfully reading, the byte value is available in the ReceivedInt property.
treatAsUnsignedInt := 1;
success := sock.ReceiveByte(treatAsUnsignedInt);
if (success = 0) then
  begin
    Memo1.Lines.Add(sock.LastErrorText);
    Exit;
  end;

// Let's look at the value of the byte received.  It should be 96.
Memo1.Lines.Add(IntToStr(sock.ReceivedInt));

// The echo server also echoed the LF back.
success := sock.ReceiveByte(treatAsUnsignedInt);
// Assuming success..

// Should be decimal 10.
Memo1.Lines.Add(IntToStr(sock.ReceivedInt));
end;