I want to send keystrokes to multiple processes. For example, if I press “1”, then I want to send the “1” to 3 "Notepad windows". Frist I want to try to send a keystroke to notepad, but it fails on the HWND:

    //HANDLE hWin; 
    HWND windowHandle = FindWindowA(NULL, "Notepad");   //Can’t find a proccess

    //Send a key
    if( windowHandle ) //This one fails
    {
        while(true)
        {
            if( GetAsyncKeyState(VK_F12) != 0 )
            {
                SendMessageA(windowHandle, WM_KEYDOWN, VK_NUMPAD1, 0); 
                Sleep(1000); 
                SendMessageA(windowHandle, WM_KEYUP, VK_NUMPAD1, 0);
            }
                    Sleep(100);
        }
    }

But the "FindWindow" method is not good enough for my program. There is also no way to get 3 different processes with the same name. So how can I make 3 handles to 3 different processes with the same name? And how can I send key’s to the processes?