Fmt

Formatting in C++ has long meant choosing between printf, which is terse but unsafe, and iostreams, which are type safe but verbose. {fmt} is an open source library that offers a third option: a compact format string syntax that is checked at compile time. It supports positional arguments for localization, Unicode output, and formatting for chrono and ranges types. The project is MIT licensed and its syntax became the basis for std::format in C++20, so code written against it maps closely onto the standard library.