switching std::string std::wstring embedded applications?

up until i have controlling std::string c++ applications embedded component (routers, switches, telco gear, etc.).

for unbroken project, i am deliberation switch std::string std::wstring unicode support. would, example, grant end-users chinese characters management line interface (cli).

what complications / headaches / surprises should i expect? what, example, i third-party library still uses std::string?

since support general strings isn't cunning requirement form embedded systems i work on, i wholly isn't going means vital headaches.