Узнать HWND главного окна процесса имея его имя?

    HWND hwnd;
    hwnd = FindWindow(0,"calc.exe");
    Label2->Caption = IntToStr(hwnd);

DWORD GetPIDbyName(LPTSTR szProcessName)
{
    HANDLE hSnapShot;
    PROCESSENTRY32 pe = {sizeof(pe)};
    hSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0); 
    if (hSnapShot == INVALID_HANDLE_VALUE)
        return 0;
    if (!Process32First(hSnapShot, &pe))
        return 0;
    do
        if(!lstrcmpi(pe.szExeFile,szProcessName))
        {
            CloseHandle(hSnapShot);
            return pe.th32ProcessID;
        }
    while (Process32Next(hSnapShot, &pe));
    CloseHandle(hSnapShot);
    return 0;
}

    HWND w = find_main_window(GetPIDbyName(process_name));

struct handle_data
{
    unsigned long process_id;
    HWND window_handle;
};
BOOL is_main_window(HWND handle)
{
    return GetWindow(handle, GW_OWNER) == (HWND)0 && IsWindowVisible(handle);
}
BOOL CALLBACK enum_windows_callback(HWND handle, LPARAM lParam)
{
    handle_data& data = *(handle_data*)lParam;
    unsigned long process_id = 0;
    GetWindowThreadProcessId(handle, &process_id);
    if (data.process_id != process_id || !is_main_window(handle))
        return TRUE;
    data.window_handle = handle;
    return FALSE;
}
 
 
 
HWND find_main_window(unsigned long process_id)
{
    handle_data data;
    data.process_id = process_id;
    data.window_handle = 0;
    EnumWindows(enum_windows_callback, (LPARAM)&data);
    return data.window_handle;
}

EnumWindows(enum_windows_callback, (LPARAM)&data);

    ::EnumWindows((WNDENUMPROC)enum_windows_callback, (LPARAM)&data);

HWND find_main_window(unsigned long process_id)
{
    handle_data data;
    data.process_id = process_id;
    data.window_handle = 0;
    ::EnumWindows((WNDENUMPROC)enum_windows_callback, (LPARAM)&data);
    //EnumWindows(enum_windows_callback, (LPARAM)&data);
    return data.window_handle;
}

HWND w = find_main_window(GetPIDbyName(process_name));