dynamic dll reloading

reload.cpp

    //------------------------------------------------------------------------------
    static error_code load_editor_dll()
    {
        char path[MAX_PATH];
        GetModuleFileNameA(NULL, path, MAX_PATH);

        char* last_slash = strrchr(path, '\\');
        if (!last_slash)
            return make_error_code(error::error_finding_editor_dll);

        strcpy(last_slash, "\\editor.dll");

        if (!file_exists(path))
        {
            return make_error_code(error::error_finding_editor_dll);
        }

        // check if the version of the dll is newer than what we have loaded
        time_t t = last_modification(path);
        if (t > _last_mod_time)
        {
            // copy the dll to a tmp file
            string dest = get_temp_filename();
            CopyFileA(path, dest.c_str(), FALSE);

            // try to load dll and get procs before closing the existing dll
            u32 old_error_mode = SetErrorMode(SEM_FAILCRITICALERRORS);
            HMODULE tmp_module = LoadLibrary(dest.c_str());
            SetErrorMode(old_error_mode);
            if (!tmp_module)
                return make_error_code(error::error_loading_editor_dll);

            fn_editor_init tmp_init = (fn_editor_init)GetProcAddress(tmp_module, "init");
            if (!tmp_init)
            {
                LOG_WARNING("Unable to find 'init' in editor dll");
                return make_error_code(error::error_loading_editor_dll);
            }

            fn_editor_close tmp_close = (fn_editor_close)GetProcAddress(tmp_module, "close");
            if (!tmp_close)
            {
                LOG_WARNING("Unable to find 'close' in editor dll");
                return make_error_code(error::error_loading_editor_dll);
            }

            // looks good, so close existing module and do the swap
            if (_editor_module)
            {
                g_editor_state->save(_json_state);
                save_file(_state_path.c_str(), _json_state.dump(4));
                _editor_close();

                FreeLibrary(_editor_module);
            }

            _editor_module = tmp_module;
            _editor_init = tmp_init;
            _editor_close = tmp_close;

            if (!_editor_init(g_engine_state, &g_editor_state))
                return make_error_code(error::error_initializing_editor);

            g_editor_state->load(_json_state);
            _last_mod_time = t;

            // delete any old temp files
            for (const string& str : _tempfiles)
            {
                DeleteFileA(str.c_str());
            }
            _tempfiles.clear();
            _tempfiles.insert(dest);


        }

        return error_code();
    }