SetWindowsHookEx

1 HHOOK WINAPI SetWindowsHookEx(
2 __in int idHook,//勾子类型
3 __in HOOKPROC lpfn,//回调函数的地址
4 __in HINSTANCE hMod,//一般为HInstance
5 __in DWORD dwThreadId,//关联进程的句柄,如果0则关联所有正在运行的进程，全局勾子时为0
6);

勾子类型为下面的值

2.定义勾子的回调函数（hook procedure），回调函数CallWndProc callback function的定义如下

An application-defined or library-defined callback function used with the SetWindowsHookEx function. The system calls this function before calling the window procedure to process a message sent to the thread

LRESULT CALLBACK CallWndProc(
  __in  int nCode,
  __in  WPARAM wParam,
  __in  LPARAM lParam
);