program BeginEndThread;

{$I ../Impl.inc}

{$I ../Includes.inc}

Classes,

System.SysUtils;

function Fibonacci(N: Integer): Integer;

if N < 0 then

raise Exception.Create('The Fibonacci sequence is not defined for negative integers.');

case N of

0: Result:= 0;

1: Result:= 1;

else

Result := Fibonacci(N - 1) + Fibonacci(N - 2);

end;

end;

F1, F2, F3: TAsymmetric<Integer, string>;

ThreadedFibo: TAsymmetricRoutine<Integer, string>;

ThreadedFibo := function(const N: Integer): string

var

Thread1, Thread2, Thread3: LongWord;

Fibo: Integer;

begin

Thread1 := TThread.CurrentThread.ThreadID;

// Switch to New thread

BeginThread;

Thread2 := TThread.CurrentThread.ThreadID;

// calculation in context of other thread

Fibo := Fibonacci(N);

// return to caller thread

// It is usefull if you have initiated process in MainThread for example

// and after that you wish return to Main thread and Paint results on GUI

EndThread;

Thread3 := TThread.CurrentThread.ThreadID;

Result := Format('Fibo(%d) = %d; Thread1=%d, Thread2=%d, Thread3=%d',

[N, Fibo, Thread1, Thread2, Thread3]);

end;

F1 := TAsymmetric<Integer, string>.Spawn(ThreadedFibo, 10);

F2 := TAsymmetric<Integer, string>.Spawn(ThreadedFibo, 20);

F3 := TAsymmetric<Integer, string>.Spawn(ThreadedFibo, 30);

Join([F1, F2, F3]);

Writeln(Format('F1.GetResult = "%s"', [F1.GetResult]));

Writeln(Format('F2.GetResult = "%s"', [F2.GetResult]));

Writeln(Format('F3.GetResult = "%s"', [F3.GetResult]));

Readln;

end.