Delphi DLL

Understanding Async Function Return Values

See more Async Examples

Explains how to get the return value of the function called synchonously in the background thread. Delphi DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
sock: HCkSocket;
task: HCkTask;
count: Integer;
s: PWideChar;
connection: HCkSocket;
acceptedConnection: HCkSocket;

begin
success := False;

// Some Chilkat functions can be called asynchronously.
// If a function "Func" can be called asynchronously, there will be a corresponding "FuncAsync" function that returns a Task object.
// 
// When Task.Run is called, the synchronous "Func" runs in a background thread.
// 

// For Chilkat methods that return a status (True/False), get returned value by calling GetResultBool.
// For example..

sock := CkSocket_Create();

// --------------------------------------------------------------
// Synchronous call returning True/False
success := CkSocket_Connect(sock,'example.com',443,True,5000);

// --------------------------------------------------------------
// Asynchronous call
task := CkSocket_ConnectAsync(sock,'example.com',443,True,5000);
// ...
CkTask_Run(task);
// ...
// ...
// Get the status (True/False) value returned by the synchronous method called in the background thread.
success := CkTask_GetResultBool(task);

// --------------------------------------------------------------
// Synchronous call returning an integer
count := CkSocket_ReceiveCount(sock);

// --------------------------------------------------------------
// Asynchronous call
task := CkSocket_ReceiveCountAsync(sock);
// ...
CkTask_Run(task);
// ...
// ...
// Get the integer value returned by the synchronous method called in the background thread.
count := CkTask_GetResultInt(task);

// --------------------------------------------------------------
// Synchronous call returning an string
s := CkSocket__receiveString(sock);

// --------------------------------------------------------------
// Asynchronous call
task := CkSocket_ReceiveStringAsync(sock);
// ...
CkTask_Run(task);
// ...
// ...
// Get the string value returned by the synchronous method called in the background thread.
s := CkTask__getResultString(task);

// --------------------------------------------------------------
// Synchronous call returning an object
connection := CkSocket_AcceptNextConnection(sock,5000);

// --------------------------------------------------------------
// Asynchronous call
task := CkSocket_AcceptNextConnectionAsync(sock);
// ...
CkTask_Run(task);
// ...
// ...
// Get the object returned by the synchronous method called in the background thread.
// We do this a little differently.  We create an new object of the same type,
// and then load it with the returned object (assuming it was not null).
acceptedConnection := CkSocket_Create();
if (CkTask_getTaskSuccess(task) = True) then
  begin
    success := CkSocket_LoadTaskResult(acceptedConnection,task);
  end;

CkSocket_Dispose(sock);
CkSocket_Dispose(acceptedConnection);

end;