NVDA backend initialization failed

[small18]

summary

Called when I am running in NVDA initialize function, returns the Already initialized, then prism doesn't seem to recognize NVDA back end.

When I use the zdsr backend test, it is normal and can be initialized.

versions

prism0.17.3
nvda 2026.1.1 (2026.1.1.55980)

[ethindp]

@small18 Can you provide more detail? Like: what code were you using to produce this problem?

[small18]

@ethindp

hi

My nvgt project requires prism. Because I don't know much about c + +, I asked codex to write the prism plug-in integration.
Integrated in the plug-in initialize function, called automatically when the program starts,However, once NVDA is running, prism fails to initialize.

The following are the initialization functions that codex integrated for me:

static bool prism_initialize() {
	std::lock_guard<std::mutex> lock(g_mutex);
	if (g_backend) return true;
	g_last_error.clear();
	wchar_t plugin_path[MAX_PATH] = {};
	GetModuleFileNameW(g_plugin_module, plugin_path, MAX_PATH);
	std::wstring prism_path(plugin_path);
	size_t separator = prism_path.find_last_of(L"\\/");
	prism_path = (separator == std::wstring::npos ? L"" : prism_path.substr(0, separator + 1)) + L"prism.dll";
	g_library = LoadLibraryW(prism_path.c_str());
	if (!g_library) {
		g_last_error = "Unable to load prism.dll (Windows error " + std::to_string(GetLastError()) + ")";
		return false;
	}
	if (!load_symbol(p_config_init, "prism_config_init") || !load_symbol(p_init, "prism_init") ||
		!load_symbol(p_shutdown, "prism_shutdown") || !load_symbol(p_create_best, "prism_registry_create_best") ||
		!load_symbol(p_backend_free, "prism_backend_free") || !load_symbol(p_backend_initialize, "prism_backend_initialize") ||
		!load_symbol(p_backend_speak, "prism_backend_speak") || !load_symbol(p_backend_braille, "prism_backend_braille") ||
		!load_symbol(p_backend_stop, "prism_backend_stop") ||
		!load_symbol(p_backend_name, "prism_backend_name") || !load_symbol(p_error_string, "prism_error_string")) {
		unload_prism();
		return false;
	}
	PrismConfig config = p_config_init();
	g_context = p_init(&config);
	if (!g_context) {
		g_last_error = "Prism could not create a context";
		unload_prism();
		return false;
	}
	g_backend = p_create_best(g_context);
	if (!g_backend) {
		g_last_error = "No supported Prism speech backend was found";
		unload_prism();
		return false;
	}
	PrismError error = p_backend_initialize(g_backend);
	if (error != 0) {
		g_last_error = p_error_string(error);
		unload_prism();
		return false;
	}
	return true;
}