Check Whether a Socket Is Writable

See more Socket/SSL/TLS Examples

Demonstrates Socket.CheckWriteable, which waits for the connected socket to become writable. It returns 1 if writable, 0 if it did not become writable before the timeout, or -1 on error.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Socket;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  socket: TSocket;
  bTls: Boolean;
  maxWaitMs: Integer;
  writable: Integer;

begin
  success := False;

  socket := TSocket.Create;

  //  Connect to the server using TLS.
  bTls := True;
  maxWaitMs := 5000;
  success := socket.Connect('example.com',5000,bTls,maxWaitMs);
  if (success = False) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;

  //  Wait up to 5 seconds for the socket to become writable.  Returns 1 if writable, 0 if it did not
  //  become writable before the timeout, or -1 on error.
  writable := socket.CheckWriteable(5000);
  if (writable < 0) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;
  if (writable <> 1) then
    begin
      WriteLn('The socket did not become writable before the timeout.');
      Exit;
    end;
  WriteLn('The socket is writable.');


  socket.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.