The smallest public printf implementation for its feature set.

rt_vsnprintf完整功能版本 | Fully functional version of rt_vsnprintf

callback_printf enables portable sprintf, snprintf, vsprintf and vsnprintf like functions. The code includes samples for those functions. It's fast, threadsafe and without dependencies to other libraries. It supports all formats of C 11 standard. wchar_t arguments and strings are converted to UTF-8.