SetEvent/ResetEvent

SetEvent/ResetEvent

分类： Visual C++ 2008 2011-08-30 10:07  1910人阅读  评论(0)  收藏  举报

winapi null thread object system

　　在自动重置事件对象中，当WaitSingleObject/WaitForMultipleObjects接收到SetEvent发送过来的信号后则返回WAIT_OBJECT_0，此时操作系统（待定）自动重置等待的事件对象（即自动将其设置为无信号状态。无论何时通过SetEvent发送过来的信号，只要未被接收到均不会被自动重置。但在未被接收之前可以调用ResetEvent手动重置等待的事件对象，此时等待的事件对象为无信号状态）。在手动重置事件对象中，当WaitSingleObject/WaitForMultipleObjects接收到SetEvent发送过来的信号后则返回WAIT_OBJECT_0，此时需要调用ResetEvent手动重置等待的事件对象（即手动将其设置为无信号状态）。

[cpp]  view plain copy

 #include <windows.h>
 #include <iostream>
 using namespace std;

 DWORD WINAPI ThreadProc(LPVOID lpParam);
 DWORD WINAPI ThreadProc2(LPVOID lpParam);

 DWORD g_dwThreadID;
 DWORD g_dwThreadID2;

 UINT g_nTickets = 300;
 HANDLE g_hEvent = NULL;

 int main(int argc, char* argv[])
 {
  cout << "Main thread is running." << endl;

  HANDLE hHandle = CreateThread(NULL, 0, ThreadProc, NULL, 0, &g_dwThreadID);
  HANDLE hHandle2 = CreateThread(NULL, 0, ThreadProc2, NULL, 0, &g_dwThreadID2);
  CloseHandle(hHandle);
  CloseHandle(hHandle2);

  g_hEvent = CreateEvent(NULL, FALSE,  TRUE, NULL);

  Sleep(4000);
  system("pause");
  return 0;
 }

 DWORD WINAPI ThreadProc(LPVOID lpParam)
 {
  // cout << "No." << g_dwThreadID << " thread is running." << endl;
  while (TRUE)
  {
   WaitForSingleObject(g_hEvent, INFINITE);
   if (g_nTickets > 0)
   {
    Sleep(1);
    cout << "No.1-" << g_dwThreadID << " sell ticket : " << g_nTickets << endl;
    g_nTickets--;
    SetEvent(g_hEvent);
   }
   else
   {
    break;
   }
  }
  return 0;
 }

 DWORD WINAPI ThreadProc2(LPVOID lpParam)
 {
  // cout << "No." << g_dwThreadID2 << " thread is running." << endl;
  while (TRUE)
  {
   WaitForSingleObject(g_hEvent, INFINITE);
   if (g_nTickets > 0)
   {
    Sleep(1);
    cout << "No.2-" << g_dwThreadID2 << " sell ticket : " << g_nTickets << endl;
    g_nTickets--;
    SetEvent(g_hEvent);
   }
   else
   {
    break;
   }
  }
  return 0;
 }