dll hook function not called

Question

I trying to catch and retranslate keyboard and mouse events. So I use SetWindowsHookEx and function in dll. First time Ш have one big error - GetProcAddress can't get my function. That answer help me a lot GetProcAddress returns NULL

Now i can call functions from dll and I can see effect from hook: my keyboard not work while programm is run. But hook not called.

main.cpp

#include <Windows.h>
#include <WinUser.h>
#include <iostream>
#include <fstream>
using namespace std;
HHOOK hhk;


int main(){
    HINSTANCE hinstLib = LoadLibrary(TEXT("hookdll.dll")); 
    typedef void (*Install)();
    typedef void (*Uninstall)();
    typedef LRESULT (_stdcall *HookProcedure)(int, WPARAM , LPARAM );
    Install install = (Install) GetProcAddress(hinstLib, "install");
    Uninstall uninstall = (Uninstall) GetProcAddress(hinstLib, "uninstall");
    HookProcedure hookProc = (HookProcedure) GetProcAddress(hinstLib, "_hookProcedure@12");//omg
    cout << GetLastError()<< "\n";
    install();
    hhk = SetWindowsHookEx(WH_KEYBOARD, hookProc, hinstLib, NULL);
    cout << GetLastError()<< "\n";
    for(int i = 0; i < 50; i++){
        Sleep(200);
        cout << i << "\n";
    }
    UnhookWindowsHookEx(hhk);
    uninstall();
    return 0;
}

hookdll.cpp

#include <Windows.h>
#include <iostream>
#include <fstream>

HINSTANCE hinst;
HHOOK hhk;
std::ofstream myfile;

extern "C" __declspec(dllexport)
LRESULT CALLBACK hookProcedure(int code, WPARAM w, LPARAM l)
{
    MessageBox(NULL, (LPCWSTR)L"HEY HEY", (LPCWSTR)L"Test", MB_OK);
    //never saw this message
    return CallNextHookEx(NULL, code, w, l);
}

extern "C" __declspec(dllexport) void install() { 
    myfile.open("log.txt",std::ios_base::app);
    myfile << "\ninstall " << GetLastError();
}
extern "C" __declspec(dllexport) void uninstall() {
    myfile << "\nuninstall " << GetLastError();
    myfile.close();
}

extern "C" __declspec(dllexport)
BOOL WINAPI DllMain(  __in  HINSTANCE hinstDLL, __in  DWORD fdwReason, __in  LPVOID lpvReserved) {
    hinst = hinstDLL;
    return TRUE;
}

score 1 · Accepted Answer · answered May 26 '13 at 18:44

1

The keyboard hook allows you to intercept WM_KEYDOWN and WM_KEYUP window messages. Console applications do not receive these messages unless there is an active windows message queue. If you want to see and process these messages in a console application create a window and give it keyboard focus. Make sure you do message pumping with the GetMessage and DispatchMessage WinAPI calls in the thread that owns the window.

If you do not want to create a window you can use WH_KEYBOARD_LL to intercept keyboard related messages sent to the active message queue of a thread. You will still need to use GetMessage to read from the queue or it will eventually start dropping messages.

answered May 26 '13 at 18:44

Captain Obvlious

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Thanks for answer. Let me check if I understand the purpose of hooks. I think that my procedure is global and catch every events. If Im not right may be I need another function in winapi? I also trying use `SetWindowsHookEx(WH_KEYBOARD_LL,..)` - result is similiar. – vlastachu May 26 '13 at 19:02
**Thank you!** To other who read this question: next question that i found by keywords http://stackoverflow.com/questions/7458807/why-must-setwindowshookex-be-used-with-a-windows-message-queue It seems strange and I can't believe that process that call dll and link procedure and link to hook also should do infinite loop. – vlastachu May 26 '13 at 19:31
Keep in mind that if you are installing a global hook your DLL will get injected into any application that the hook can be applied to. – Captain Obvlious May 26 '13 at 19:39

dll hook function not called

1 Answers1