diff --git a/examples/proto_debuger/modbus_form.cpp b/examples/proto_debuger/modbus_form.cpp
index 761f0119..072d30eb 100644
--- a/examples/proto_debuger/modbus_form.cpp
+++ b/examples/proto_debuger/modbus_form.cpp
@@ -91,7 +91,7 @@ void ModbusMasterForm::Init() {
 		mBtnSend->AttachClick([this](ui::EventArgs*){
 			wprintf(L"com is %s m_name", m_name.c_str());
 			printf("open ptr is  %s %d %d %d    ", wstring2string(m_name).c_str(), m_baurate,m_data_bits,m_stop_bits);
-			mModbus = modbus_new_rtu(wstring2string(wstring(L"\\\\.\\") + m_name),
+			mModbus = modbus_new_rtu(wstring2string(wstring(L"\\\\.\\") + m_name).c_str(),
 				m_baurate,'N',m_data_bits, m_stop_bits);
 
 			if (mModbus != nullptr) {