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async_simple is a library offering simple, light-weight and easy-to-use components to write asynchronous code. The components offered include Lazy (based on C++20 stackless coroutine), Uthread (based on stackful coroutine) and the traditional Future/Promise.

We can try async_simple online in compiler-explorer. Note that Uthread cannot be use in compiler-explorer since it requires installation.

Our documents are hosted by GitHub Pages, go to Get Started.

After installing and reading Lazy to get familiar with API, here is a demo use Lazy to count char in a file.

vcpkg is a cross-platform package manager.

./vcpkg install async-simple

git clone -b main --single-branch --depth 1 https://github.com/alibaba/async_simple.git
cd async_simple
mkdir build
cd build
cmake .. -DASYNC_SIMPLE_ENABLE_TESTS=OFF -DASYNC_SIMPLE_ENABLE_BENCHMARKS=OFF -DASYNC_SIMPLE_BUILD_DEMO_EXAMPLE=OFF -DASYNC_SIMPLE_ENABLE_ASAN=OFF
cmake --build .
cmake --install . # --prefix ./user_defined_install_path

After install async_simple, you can import it to your project.

Please add those cmake code:

find_package(async_simple REQUIRED)
target_link_libraries(<your-target-name> PRIVATE async_simple::async_simple) # dynamic_link
                                 # async_simple::async_simple_header_only
                                 # async_simple::async_simple_static

<your-target-name> is the target name which want to use async_simple

async_simple is almost header-only. So you can just pass the include path of the install position to your compiler.

But the uthread part of async_simple is not head-only. If you want to use uthread, You need link it manually. The library file is in the install path.

Required Compiler: clang (>= 10.0.0) or gcc (>= 10.3) or Apple-clang (>= 14)

Note that we need to add the -Wno-maybe-uninitialized option when we use gcc 12 due to a false positive diagnostic message by gcc 12

If you're using async_simple::Generator, there may be some compiler bugs in clang15. We suggest to use clang17 or higher for that.

If you meet any problem about MSVC Compiler Error C4737. Try to add the /EHa option to fix the problem.

The build of async_simple requires libaio, googletest and cmake. Both libaio and googletest are optional. (Testing before using is highly suggested.) By default, async_simple would try to clone the googletest from git to make sure the version used is correct. But in case the users have problems with networks, users can try to install the gtest libraries by the following instructions and use the CMake variables ('GMOCK_INCLUDE_DIR', 'GTEST_LIBRARIES', 'GMOCK_INCLUDE_DIR', 'GMOCK_LIBRARIES') to specify the location.

# Install libaio
sudo apt install libaio-dev -y
# Install cmake
sudo apt install cmake -y
# Install bazel See: https://bazel.build/install/ubuntu

• Use apt to install gtest and gmock

sudo apt install -y libgtest-dev libgmock-dev

• Try to build gtest and gmock from source

# Install gtest
sudo apt install libgtest-dev -y
sudo apt install cmake -y
cd /usr/src/googletest/gtest
sudo mkdir build && cd build
sudo cmake .. && sudo make install
cd .. && sudo rm -rf build
cd /usr/src/googletest/gmock
sudo mkdir build && cd build
sudo cmake .. && sudo make install
cd .. && sudo rm -rf build

# Install bazel See: https://bazel.build/install/ubuntu

# Install libaio
sudo yum install libaio-devel -y

• Use yum to install gtest, gmock

sudo yum install gtest-devel gmock-devel

• Try to build gtest and gmock from source

# Optional
sudo pacman -S libaio
# Use cmake to build project
sudo pacman -S cmake gtest
# Use bazel to build project
sudo pacman -S bazel

# Use cmake to build project
brew install cmake
brew install googletest
# Use bazel to build project
brew install bazel

# Install cmake
winget install cmake
# Install google-test
# TODO
# Install bazel See: https://bazel.build/install/windows

# libaio (optional)
# you can skip this if you install libaio from packages
git clone https://pagure.io/libaio.git
cd libaio
sudo make install
# gmock and gtest
git clone git@github.com:google/googletest.git -b v1.8.x
cd googletest
mkdir build && cd build
cmake .. && sudo make install

Demo example depends on standalone asio(https://github.com/chriskohlhoff/asio/tree/master/asio), the commit id:f70f65ae54351c209c3a24704624144bfe8e70a3

$ mkdir build && cd build
# Specify [-DASYNC_SIMPLE_ENABLE_TESTS=OFF] to skip tests.
# Specify [-DASYNC_SIMPLE_ENABLE_BENCHMARKS=ON] to enable optional benchmark discovery and targets.
# Specify [-DASYNC_SIMPLE_BUILD_DEMO_EXAMPLE=OFF] to skip build demo example.
# Specify [-DASYNC_SIMPLE_DISABLE_AIO=ON] to skip the build libaio
CXX=clang++ CC=clang cmake ../ -DCMAKE_BUILD_TYPE=[Release|Debug] [-DASYNC_SIMPLE_ENABLE_TESTS=OFF] [-DASYNC_SIMPLE_ENABLE_BENCHMARKS=ON] [-DASYNC_SIMPLE_BUILD_DEMO_EXAMPLE=OFF] [-DASYNC_SIMPLE_DISABLE_AIO=ON] [-DGMOCK_INCLUDE_DIR=<path-to-headers of gtest> -DGTEST_INCLUDE_DIR=<path-to-headers of mock> -DGTEST_LIBRARIES=<path-to-library-of-gtest>  -DGMOCK_LIBRARIES=<path-to-library-of-gmock> ]
# for gcc, use CXX=g++ CC=gcc
make -j4
make test # optional
make install # sudo if required

ASYNC_SIMPLE_ENABLE_BENCHMARKS defaults to OFF, so Benchmark discovery and benchmark targets are skipped. Set it to ON to build benchmarks when both the Benchmark headers and library are available. Set it back to OFF to skip discovery and targets even when reusing a build directory with cached Benchmark paths. Existing build directories retain their cached option value; pass OFF explicitly to disable benchmarks in a directory previously configured with ON.

Run the benchmark-option configure regression tests from the repository root:

python3 cmake/tests/test_benchmark_option.py

These tests require Python 3, CMake, Ninja and a supported C++ compiler. They use placeholder Benchmark paths to check configuration traces and generated targets; they do not build or run benchmarks. Package unavailability is simulated by disabling Benchmark discovery.

Conan is also supported. You can install async_simple to conan local cache.

mkdir build && cd build
conan create ..

# Specify [--define=ASYNC_SIMPLE_DISABLE_AIO=true] to skip the build libaio
# Example bazel build --define=ASYNC_SIMPLE_DISABLE_AIO=true ...
bazel build ...                      # compile all target
bazel build ...:all                  # compile all target
bazel build ...:*                    # compile all target
bazel build -- ... -benchmarks/...   # compile all target except those beneath `benchmarks`
bazel test ...                       # compile and execute tests
# Specify compile a target
# Format: bazel [build|test|run] [directory name]:[binary name]
# Example
bazel build :async_simple           # only compile libasync_simple
bazel run benchmarks:benchmarking   # compile and run benchmark
bazel test async_simple/coro/test:async_simple_coro_test
# Use clang toolchain
bazel build --action_env=CXX=clang++ --action_env=CC=clang ...
# Add compile option
bazel build --copt='-O0' --copt='-ggdb' ...
# Extracts compile_commands.json
# If you want to specify additional flags for targets, please refer to:
# https://github.com/hedronvision/bazel-compile-commands-extractor
bazel run @hedron_compile_commands//:refresh_all

• See this to get more information
• ... Indicates recursively scan all targets, recognized as ../.. in oh-my-zsh, can be replaced by other shell or bash -c 'commond' to run, such as bash -c 'bazel build' ... or use bazel build ...:all
• Use async_simple as a dependency, see also bazel support

git clone https://github.com/alibaba/async_simple.git
cd async_simple/docker/(ubuntu|centos7|rockylinux)
docker build . --no-cache -t async_simple:1.0
docker run -it --name async_simple async_simple:1.0 /bin/bash

We also give a Quantitative Analysis Report of Lazy (based on C++20 stackless coroutine) and Uthread (based on stackful coroutine).

We have experimental support for C++20 Modules in modules/async_simple.cppm. We can build the async_simple module by xmake and cmake. We can find the related usage in CountChar, ReadFiles, LazyTest.cpp and FutureTest.cpp.

We need clang (>= d18806e6733 or simply clang 16) to build the async_simple module. It is only tested for libstdc++10.3. Due to the current support status for C++20, it won't be a surprise if the compilation fails in higher versions of STL.

We can build the async_simple module with xmake (>= 0eccc6e) using the commands:

xmake

We can build the async_simple module with cmake (>= d18806e673 or cmake 3.26 and up) using the following commands:

mkdir build_modules && cd build_modules
CC=clang CXX=clang++ cmake .. -DCMAKE_BUILD_TYPE=Release -DASYNC_SIMPLE_BUILD_MODULES=ON -GNinja
ninja

If std module is available, we can define -DSTD_MODULE_AVAILABLE=ON when configuring cmake to use std modules provided by vendors.

Note that the async_simple module in the main branch is actually a named module's wrapper for headers for compatibility. We can find the practical usage of C++20 Modules in https://github.com/alibaba/async_simple/tree/CXX20Modules, which contains the support for xmake and cmake as well.

For questions, we suggest to read docs, issues and discussions first. If there is no satisfying answer, you could file an issues or start a thread in discussions. Specifically, for defect report or feature enhancement, it'd be better to file an issues. And for how-to-use questions, it'd be better to start a thread in discussions.

1. Read the How to fix issue document firstly.
2. Run tests and git-clang-format HEAD^ locally for the change. Note that the version of clang-format in CI is clang-format 14. So that it is possible your local format result is inconsistency with the format result in the CI. In the case, you need to install the new clang-format or adopt the suggested change by hand. In case the format result is not good, it is OK to accept the PR temporarily and file an issue for the clang-formt.
3. Create a PR, fill in the PR template.
4. Choose one or more reviewers from contributors: (e.g., ChuanqiXu9, RainMark, foreverhy, qicosmos).
5. Get approved and merged.

async_simple is distributed under the Apache License (Version 2.0) This product contains various third-party components under other open source licenses. See the NOTICE file for more information.