带有 WH_KEYBOARD 的 SetWindowsHookEx 卡在循环/队列中

Posted 2023-02-22

【中文标题】带有 WH_KEYBOARD 的 SetWindowsHookEx 卡在循环/队列中

【英文标题】：SetWindowsHookEx with WH_KEYBOARD stuck in a loop/queue

【发布时间】：2014-10-04 18:51:34

【问题描述】：

我正在尝试使用 dll 注入挂钩记事本。在运行 exe 并挂接记事本（形成我可以成功告诉的内容）并按下一些键后，似乎发生的事情是按键卡在循环或队列中（记事本没有响应）。 exe 解开挂钩后，记事本会做出响应，并且所有按下的键都会出现在文本字段中。

exe

#include <iostream>
#include <fstream>
#include <windows.h>
#include <stdio.h>

HHOOK       hHook     = NULL;
HWND        handle    = NULL;
HMODULE     dll       = NULL;
HOOKPROC    address   = NULL;
DWORD       thread_id = 0;

using namespace std;

int main()

    handle=FindWindow(NULL,L"Untitled - Notepad");
    if(handle==NULL)
        cout<<"Window not found"<<endl;
        getchar();
        return 0;
    

    thread_id=GetWindowThreadProcessId(handle,NULL);
    if(thread_id==0)
        cout<<"ID not found"<<endl;
        getchar();
        return 0;
    

    dll = LoadLibrary(TEXT("X:\\qt\\hook\\debug\\hook.dll"));
    if(dll==NULL)
        cout<<"hook.dll not found"<<endl;
        getchar();
        return 0;
    

    address=(HOOKPROC)GetProcAddress(dll,"CallWndProc@12");
    if(address==NULL)
        cout<<"Address not found"<<endl;
        getchar();
        return 0;
    

    hHook=SetWindowsHookEx(WH_KEYBOARD,address,dll,thread_id);
    if(hHook==NULL)
        cout<<"hook was not set"<<endl;
        return 0;
    

    cout<<"Program successfully hooked"<<endl;
    cout<<"Press enter to unhook the function and stop the program"<<endl;
    getchar();
    UnhookWindowsHookEx(hHook);

    return 0;

dll

#include "hook.h"
#include <windows.h>
#include <iostream>
#include <fstream>

using namespace std;

extern "C"
    __declspec(dllexport) LRESULT CALLBACK CallWndProc(int nCode,WPARAM wParam,LPARAM lParam)

        if(nCode<0)
           return CallNextHookEx(NULL,nCode,wParam,lParam);
        

        ofstream file;
        file.open("X:\\qt\\klog\\debug\\function.txt");
        file<<"Function keyboard_hook called\n";
        file.close();
        return CallNextHookEx(NULL,nCode,wParam,lParam);
    


BOOL APIENTRY DllMain(HMODULE hDLL, DWORD Reason, LPVOID Reserved)

    switch(Reason) 
    case DLL_PROCESS_ATTACH: break;
    case DLL_PROCESS_DETACH: break;
    case DLL_THREAD_ATTACH:  break;
    case DLL_THREAD_DETACH:  break;
    

    return TRUE;

【问题讨论】：

来自KeyboardProc callback function页面：This hook may be called in the context of the thread that installed it. The call is made by sending a message to the thread that installed the hook. Therefore, the thread that installed the hook must have a message loop.

谢谢@500 不知道我是怎么错过的。

【参考方案1】：

在 SetWindowsHookEx 和 UnhookWindowsHookEx 之间添加消息循环修复了它

while(GetMessage(&Msg, NULL, 0, 0) > 0)

    TranslateMessage(&Msg);
    DispatchMessage(&Msg);