Delphi DLL

Check the IMAP Socket Connection

Demonstrates the Chilkat Imap.CheckConnection method, which checks whether the underlying TCP socket is currently connected to the IMAP server. This performs a low-level socket-state check and does not send an IMAP command. This example connects and checks the socket.

Background: CheckConnection sits between the cached IsConnected and a full protocol round trip: it inspects the actual socket without sending an IMAP command, so it can catch a locally-closed socket that the cached flag would miss. It still cannot detect every half-open connection, though — only a real command like Noop that expects a server reply proves the session is genuinely alive end to end.

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var
success: Boolean;
imap: HCkImap;
stillConnected: Boolean;

begin
success := False;

//  Demonstrates the Imap.CheckConnection method, which checks whether the underlying TCP
//  socket is currently connected to the IMAP server.  This is a low-level socket-state check
//  and does not send an IMAP command.

imap := CkImap_Create();

CkImap_putSsl(imap,True);
CkImap_putPort(imap,993);

success := CkImap_Connect(imap,'imap.example.com');
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

//  Perform a low-level check of the socket connection state.
stillConnected := CkImap_CheckConnection(imap);
if (stillConnected = True) then
  begin
    Memo1.Lines.Add('The socket is still connected.');
  end
else
  begin
    Memo1.Lines.Add('The socket is no longer connected.');
  end;

success := CkImap_Disconnect(imap);
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

CkImap_Dispose(imap);