fast_io is a new C++20 library for extremely fast input/output and aims to replace iostream and cstdio. It is header-only (module only in the future) for easy inclusion in your project. It requires a capable C++20 compiler supporting concepts.

• VS 16.3
• Clang 10.0
• GCC 10

• Windows
• Linux
• MacOS
• Android

• Locale support optional
• Zero copy IO

• No easily misused stuff like std::endl
• No internal iomanip states (since it creates security issues)
• Providing RAII for FILE*&POSIX file id

• Unicode/UTF-8 support
• Compatible with C stdio and C++ iostream
• Binary serialization for trivially copyable types and C++ standard library containers
• All fast_io devices can be natively put in C++ containers. std::vector<fast_io::obuf> is valid
• Support C style io format (fprint). Basic/Lua/Python/etc format (print, scan).

• Exception Safe & Exception neutral
• Native Handle Interface
• Extremely easy to support custom devices
• std::mutex mutex stream
• Compilation time open mode parse. Supports C style open mode and C++ style open mode.
• No traits_type and EOF
• Dynamic Type Support
• Pipe line support
• Cryptography (Under construction) to replace openssl
• debugging IO

1. Module support
2. Coroutine support for async IO
3. Improve and refactor code once Zero-overhead deterministic exceptions are added to the standard
4. Network handle support with coroutine. (NOT ASIO library)
5. Partial freestanding mode

1. Compression/Decompression
2. Interfaces for cloud computing algorithms like MapReduce

I'm aiming for this to be in the C++ standard library in the future :)

Please see examples in the examples folder.

compile option:

g++ -o example example.cc -O2 -std=c++2a -fconcepts

./doxygen/html/index.html

Since C++ 20 has not been released. No standard supporting libraries for concepts, which means a lot of Concepts Definitions are ugly. It will be changed after C++ 20 is officially published.

output 10000000 size_t to file

/fast_io/tests# ./i

input 10000000 size_t from file

fast_io/tests ./j

output_10M_size_t.cc -O2 -std=c++2a -fconcepts

input_10M_size_t.cc -O2 -std=c++2a -fconcepts

I did some optimizations to my fast_io library. Now there is NO reason to use charconv any more. It is insecure and the APIs are terrible. I hope isocpp would deprecate charconv in the future.

fast_io/examples/