Kuro

Linux io_uring based c++ 20 coroutine library

What is "Kuro"?

Kuro is a character in Game Sekiro by FromSoftware.

In this case, it refers to a basic coroutine library, which relies on C++ 20 coroutine syntax and Linux io_uring feature, aiming to build easy, flexible and high-performance asynchronous programming framework in C++.

Example

Task<int> co_echo(std::shared_ptr<io_uring>& handle) {
  void* buf;
  TcpListener listener = TcpListener();
  TcpStream stream_ = TcpStream();

  listener.bind_socket("127.0.0.1", htons(3344));
  
  listener.listen_socket(1024);

  co_await listener.async_accept(handle, &stream_);
  
  if(posix_memalign(&buf, 1024, 1024))
    co_return 1;

  while(1) {
    int n = co_await stream_.async_recv(handle, buf, 1024);

    if (n == 0) break;

    co_await stream_.async_send(handle, buf, n);
  }

  co_return 0;
}

Build

git clone https://github.com/sekirio-rs/Kuro
cd Kuro
git submodule update --init

make # build kuro.so
make example # build examples

How to use

Kuro works as a dynamic library(.so).

First, generate the kuro.so:

cd Kuro
make
# then kuro.so will be in Kuro/build

Then include "kuro.h" in your code(xxx.cc) and compile it:

g++ -fcoroutines -std=c++20 -Wall -O2 -D_GNU_SOURCE xxx.cc -o xxx -luring -lkuro

WARNING:

• Make sure liburing.so.* be prepared in your system to successfully compiled. See https://github.com/axboe/liburing to setup it.
• Checkout your Linux kernel version. >= 5.13 will be 100% OK, otherwise may -22 be returned on some IO operations.
• Checkout your gcc(g++) version, make sure it support C++ 20 and coroutine.

See how Makefile build examples for compiling details.

License

Copyright (C) 2022 SKTT1Ryze. All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under License.