I don't think there's any concern about breaking wprintf. wprintf inherently operates by converting the argument to %s to wide characters since its output it wide characters; as such, there's no way it could avoid failing when the input is an invalid multibyte sequence unless it completely ignored the failure return.
I don't think there's any concern about breaking wprintf. wprintf inherently operates by converting the argument to %s to wide characters since its output it wide characters; as such, there's no way it could avoid failing when the input is an invalid multibyte sequence unless it completely ignored the failure return.