读书 Delphi下深入Windows核心编程 第二天

技术交流,DH讲解. 今天进入这书第二章 钩子(HOOK).
先说说钩子是什么?
钩子其实就在你环境中加上一层过滤,在特殊情况下就触发钩子回调函数.
比如说我们安装了全局的键盘钩子,那么当我们按动键盘上面的键的时候,钩子的回调函数就会触发.
我们也能看到本来是直来直往的,结果现在中间安装了一层过滤,系统的效率肯定会有所下降的.
要了解,我们只需要知道3个函数:
1 上钩函数: function SetWindowsHookEx(
idHook: Integer;//钩子的类型
lpfn: TFNHookProc; //回调函数指针
hmod: HINST; //一般为0或者Instance
dwThreadId: DWORD//全局钩子就为0,不然就为指定进程id
): HHOOK; stdcall;//成功就返回一个值,不成功就为0
其中钩子类型有:
{$EXTERNALSYM WH_MIN}
WH_MIN = -1;
{$EXTERNALSYM WH_MSGFILTER}
WH_MSGFILTER = -1;
{$EXTERNALSYM WH_JOURNALRECORD}
WH_JOURNALRECORD = 0;
{$EXTERNALSYM WH_JOURNALPLAYBACK}
WH_JOURNALPLAYBACK = 1;
{$EXTERNALSYM WH_KEYBOARD}
WH_KEYBOARD = 2;
{$EXTERNALSYM WH_GETMESSAGE}
WH_GETMESSAGE = 3;
{$EXTERNALSYM WH_CALLWNDPROC}
WH_CALLWNDPROC = 4;
{$EXTERNALSYM WH_CBT}
WH_CBT = 5;
{$EXTERNALSYM WH_SYSMSGFILTER}
WH_SYSMSGFILTER = 6;
{$EXTERNALSYM WH_MOUSE}
WH_MOUSE = 7;
{$EXTERNALSYM WH_HARDWARE}
WH_HARDWARE = 8;
{$EXTERNALSYM WH_DEBUG}
WH_DEBUG = 9;
{$EXTERNALSYM WH_SHELL}
WH_SHELL = 10;
{$EXTERNALSYM WH_FOREGROUNDIDLE}
WH_FOREGROUNDIDLE = 11;
{$EXTERNALSYM WH_CALLWNDPROCRET}
WH_CALLWNDPROCRET = 12;
{$EXTERNALSYM WH_KEYBOARD_LL}
WH_KEYBOARD_LL = 13;
{$EXTERNALSYM WH_MOUSE_LL}
WH_MOUSE_LL = 14;
{$EXTERNALSYM WH_MAX}
WH_MAX = 14;
{$EXTERNALSYM WH_MINHOOK}
WH_MINHOOK = WH_MIN;
{$EXTERNALSYM WH_MAXHOOK}
WH_MAXHOOK = WH_MAX;
具体作用基本上就看名字就知道,个别的我也不知道,具体的大家看MSDN吧.这个是个葵花宝典.

2 卸钩函数:
function UnhookWindowsHookEx(
hhk: HHOOK//上钩函数返回的句柄
): BOOL; stdcall;
3 具体的钩子回调函数:
TFNHookProc = function (code: Integer; wparam: WPARAM; lparam: LPARAM): LRESULT stdcall;
好的说了这么多,看例子: