unit1.pas

线程同步代码集很经典

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }

  end;

var
  Form1: TForm1;
  MutexHandle: THandle;
  ThreadHandle, ThreadHandle1, ThreadHandle2: THandle;
implementation

{$R *.DFM}

function ThreadFunc1(Info: Pointer): Integer; stdcall;
var
  ICount: Integer;
  CountStr: string;
begin
  WaitForSingleObject(MutexHandle, INFINITE);
  for ICount := 1 to 100000 do
  begin
    CountStr := IntToStr(ICount);
    Form1.Canvas.TextOut(10, 10, 'Thread 1 ' + CountStr);
  end;
  ReleaseMutex(MutexHandle);
  ExitThread(1);
end;

function ThreadFunc2(Info: Pointer): Integer; stdcall;
var
  ICount: Integer;
  CountStr: string;
begin
  WaitForSingleObject(MutexHandle, INFINITE);
  for ICount := 1 to 100000 do
  begin
    CountStr := IntToStr(ICount);
    Form1.Canvas.TextOut(160, 10, 'Thread 2 ' + CountStr);
  end;
  ReleaseMutex(MutexHandle);
  ExitThread(2);
end;

function ThreadFunc3(Info: Pointer): Integer; stdcall;
var
  ICount: Integer;
  CountStr: string;
  LocalMutexHandle: THandle;
begin
  LocalMutexHandle := OpenMutex(MUTEX_ALL_ACCESS, FALSE, 'MyMutex');
  WaitForSingleObject(LocalMutexHandle, INFINITE);
  for ICount := 1 to 100000 do
  begin
    CountStr := IntToStr(ICount);
    Form1.canvas.TextOut(310, 10, 'Thread 3 ' + CountStr);
  end;
  ReleaseMutex(LocalMutexHandle);
  CloseHandle(LocalMutexHandle);
  ExitThread(3);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  ThreadId1, ThreadId2, ThreadId3: DWORD;
begin
  if MutexHandle<>DWORD(-1) then
     CloseHandle(MutexHandle);
  MutexHandle := CreateMutex(nil, False, 'MyMutex');
  ThreadHandle := CreateThread(nil, 0, @ThreadFunc1, nil, 0, ThreadId1);
  ThreadHandle1 := CreateThread(nil, 0, @ThreadFunc2, nil, 0, ThreadId2);
  ThreadHandle2 := CreateThread(nil, 0, @ThreadFunc3, nil, 0, ThreadId3);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
   MutexHandle:=DWORD(-1);
end;

end.