WinAPI: GetWindow 获取与指定窗口具有指定关系的窗口的句柄

//声明:
GetWindow(
  hWnd: HWND; {指定的窗口句柄}
  uCmd: UINT  {指定的关系选项}
): HWND;      {失败返回0; 成功返回符合的窗口句柄}

//uCmd 可选值:
GW_HWNDFIRST = 0; {同级别第一个}
GW_HWNDLAST  = 1; {同级别最后一个}
GW_HWNDNEXT  = 2; {同级别下一个}
GW_HWNDPREV  = 3; {同级别上一个}
GW_OWNER     = 4; {属主窗口}
GW_CHILD     = 5; {子窗口}


//举例: http://www.cnblogs.com/del/archive/2008/02/25/1081295.html