C++ Win32 键盘事件
出于个人兴趣，我正在研究我的击键记录器，昨天问了一个与此相关的问题；While 循环使用大量 CPU.
I am working on my keystroke logger for personal interest and asked a question related to this about yesterday; While loop using a lot of CPU.
该程序的问题在于它占用了太多的 CPU 使用率，人们建议让输入基于键事件.
The issue with the program was that it took too much CPU Usage, and people have suggested to make the inputs key-event based.
由于我是 Win32 API 的新手，所以我尝试寻找参考资料和教程，它们将告诉我如何将键盘输入创建为基于事件而不是基于轮询.但问题是我找不到任何可靠的例子或参考资料，因为对于一个完整的新手来说很难理解.
Since I'm new to the Win32 API, I try to look for references and tutorials that will tell me how to create keyboard inputs as event-based, rather than poll based. But the problems is I could not found any solid examples or references, as it was quite difficult to understand for a complete newbie.
他们中的大多数人都提到基于事件的编程驻留在 GUI 应用程序中，但我希望这个击键记录器应用程序是一个控制台应用程序.
Most of them mentioned that the event-based programming resided in GUI application, yet I want this keystroke logger application to be a console application.
我的两个主要问题是:
- 我可以使用 Win32 API 编写基于事件的控制台按键记录器吗?如果没有，我有哪些选择?
和
- 有没有人有任何参考网站可以帮助我了解如何基于事件捕获击键?
如果需要更多信息，我在 Windows XP 下使用代码块和 GCC 编译器.
If additional information is needed, I am using Code Blocks under Windows XP with a GCC compiler.
推荐答案
按键记录器应用程序使用诸如 Win32 钩子.具体来说，您需要设置一个 WH_KEYBOARD 钩子.
Key logger applications use mechanisms such as Win32 Hooks. Specifically you need to set a WH_KEYBOARD hook.
有一些高级技术，比如创建自己的键盘驱动程序，但对于开始使用钩子是一个不错的选择.
There are move advanced techniques, like creating your own keyboard driver but for a start hooks are a good choice.
为了了解钩子过程的样子，我发布了我个人实用程序中的一个片段.
To get an idea of how a hook procedure looks like, I post a fragment from my personal utility.
// ...
thehook = SetWindowsHookEx( WH_KEYBOARD_LL, hook_proc, hwnd, 0 );
// ...
/**
*
* wParam, one of the: WM_KEYDOWN, WM_KEYUP, WM_SYSKEYDOWN, or WM_SYSKEYUP
lParam: pointer to a KBDLLHOOKSTRUCT structure
(*) "The hook procedure should process a message in less time than the
data entry specified in the LowLevelHooksTimeout value in the following registry key:
HKEY_CURRENT_USERControl PanelDesktop
The value is in milliseconds. If the hook procedure does not
return during this interval, the system will pass the message to the next hook."
*
*/
LRESULT CALLBACK
hook_proc( int code, WPARAM wParam, LPARAM lParam )
{
static long ctrl_cnt = 0;
static bool mmode = false;
static DWORD time;
KBDLLHOOKSTRUCT* kbd = (KBDLLHOOKSTRUCT*)lParam;
if ( code < 0
|| (kbd->flags & 0x10) // ignore injected events
) return CallNextHookEx( thehook, code, wParam, lParam );
long ret = 1; // by default I swallow the keys
if ( mmode ) { // macro mode is ON
if ( WM_KEYDOWN == wParam )
PostMessage(mainwnd, WM_MCR_ACCUM, kbd->vkCode, 0);
if ( WM_KEYUP == wParam )
switch (kbd->vkCode) {
case VK_ESCAPE:
mmode = false;
keys.removeall();
PostMessage(mainwnd, WM_MCR_HIDE, 0, 0);
break;
case VK_RETURN:
PostMessage(mainwnd, WM_MCR_EXEC, 0, 0);
break;
case VK_LCONTROL:
mmode = false;
PostMessage(mainwnd, WM_MCR_HIDE, 0, 0);
PostMessage(mainwnd, WM_MCR_EXEC, 0, 0);
break;
}
/* Which non printable keys allow passing? */
switch( kbd->vkCode ) {
case VK_LCONTROL:
case VK_CAPITAL:
case VK_LSHIFT:
case VK_RSHIFT:
ret = CallNextHookEx( thehook, code, wParam, lParam );
}
}
else { // macro mode is OFF
/* Ctrl pressed */
if ( kbd->vkCode == VK_LCONTROL && WM_KEYDOWN == wParam ) {
ctrl_cnt = 1;
time = kbd->time;
}
/* Prevent ctrl combinations to activate macro mode */
if ( kbd->vkCode != VK_LCONTROL )
ctrl_cnt = 0;
/* Ctrl released */
if ( ctrl_cnt == 1 && WM_KEYUP == wParam ) {
if ( kbd->time - time > 40 ) {
mmode = true;
PostMessage(mainwnd, WM_MCR_SHOW, 0, 0);
}
}
ret = CallNextHookEx( thehook, code, wParam, lParam ); // let it pass
}
return ret;
}
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