C++ AccessibleObjectFromWindow always return 0

Question

Hello guys,

I'm new developer windows.
I want to get ROLE_SYSTEM_TEXT of application in window but I got trouble with function AccessibleObjectFromWindow
I read the docs and try to use this fuction but it not work
Please help me fix it.
This is my code :

#include <iostream>
#include <Windows.h>
#include <OleAcc.h>
#include <unistd.h>


void get_role_system_text(){
  HWND hwnd = GetActiveWindow();
  IAccessible* pAccessible = nullptr;
    VARIANT varChild;
    varChild.vt = VT_EMPTY;

    HRESULT hr = AccessibleObjectFromWindow(hwnd, OBJID_WINDOW, IID_IAccessible, (void**)&pAccessible);
    std::cout << "AccessibleObjectFromWindow pAccessible : " << pAccessible << std::endl;
    std::cout << "AccessibleObjectFromWindow SUCCEEDED(hr) : " << SUCCEEDED(hr) << std::endl;

    if (SUCCEEDED(hr)) {
        VARIANT varRole;
        hr = pAccessible->get_accRole(varChild, &varRole);
        if (SUCCEEDED(hr) && varRole.vt == VT_I4) {
            std::cout << "Role value: " << varRole.lVal << std::endl;
        }
        pAccessible->Release();
    }
}

int main() {
    // Initialize COM
    CoInitialize(nullptr);

    while(1){
        Sleep(1000);
        get_role_system_text();
    }

    // Uninitialize COM
    CoUninitialize();

    return 0;
}

Comand build: g++ role.cpp -loleacc -lole32

Answer 1

This is a Console code and hwnd is probably NULL

Call

 HWND hwnd = GetConsoleWindow();

instead to get the Console window

or

HWND hwnd = GetForegroundWindow();

for the foreground window