Awesome Open Source
Awesome Open Source

Basic (中文)

CO is an elegant and efficient C++ base library that supports Linux, Windows and Mac platforms. It pursues minimalism and efficiency, and does not rely on third-party library such as boost.

CO includes coroutine library (golang-style), network library (tcp/http/rpc), log library, command line and configuration file parsing library, unit testing framework, json library and other basic components.



  • co

    co is a golang-style C++ coroutine library with the following features:

    • Support multi-thread scheduling, the default number of threads is the number of system CPU cores.

    • Coroutines share the thread stack (the default size is 1MB), and the memory footprint is extremely low, a single machine can easily create millions of coroutines.

    • Support system api hook (Linux & Mac).

    • Support coroutine lock co::Mutex.

    • Support coroutine synchronization event co::Event.

    • Support coroutine pool co::Pool.

    • create coroutine with go():

    void fun() {
        std::cout << "hello world" << std::endl;
  • so

    so is a C++ network library based on coroutines. You can easily write network programs that support both ipv4 and ipv6 with this library. It includes the following modules:

    • tcp module, supports general tcp programming.

    • http module, supports basic http programming.

    • rpc module, implements a rpc framework based on json, single-threaded qps can reach 120k+.

    • Write a static web server:

    #include "co/flag.h"
    #include "co/log.h"
    #include "co/so.h"
    DEF_string(d, ".", "root dir"); // Specify the root directory of the web server
    int main(int argc, char** argv) {
        flag::init(argc, argv);
        so::easy(FLG_d.c_str()); // mum never have to worry again
        return 0;
    • Write a general http server
    http::Server serv("", 80);
        [](const http::Req& req, http::Res& res) {
            if (req.is_method_get()) {
                if (req.url() == "/hello") {
                    res.set_body("hello world");
                } else {
            } else {
  • log

    log is a super fast local logging system, printing logs is safer than printf:

    LOG << "hello "<< 23;   // info
    ELOG << "hello again";  // error

    Let's see how fast it is below:

    log vs glog google glog co/log
    win2012 HHD 1.6MB/s 180MB/s
    win10 SSD 3.7MB/s 560MB/s
    mac SSD 17MB/s 450MB/s
    linux SSD 54MB/s 1023MB/s

    The above table is the test result of one million info logs (about 50 bytes each) continuously printed by a single thread. The co/log is almost two orders of magnitude faster than glog.

    Why is it so fast? The first is that it is based on fastream that is 8-25 times faster than sprintf. The second is that it has almost no memory allocation operations.

  • flag

    flag is a command line and configuration file parsing library that supports automatic generation of configuration files.

    #include "co/flag.h"
    DEF_int32(i, 32, "comments");
    DEF_string(s, "xxx", "string type");
    int main(int argc, char** argv) {
        flag::init(argc, argv);
        std::cout << "i: "<< FLG_i << std::endl;
        std::cout << "s: "<< FLG_s << std::endl;
        return 0;

    Build and run:

    ./xx                         # start with default parameters
    ./xx -i=4k -s="hello world"  # integers can take unit k,m,g,t,p (case insensitive)
    ./xx -i 4k -s "hello world"  # equivalent to above
    ./xx --mkconf                # automatically generate configuration file xx.conf
    ./xx -config=xx.conf         # start from configuration file
  • json

    json is a json library comparable to rapidjson, if you use jemalloc, the performance of parse and stringify will be further improved. This library's support for the json standard is not as comprehensive as rapidjson, but it can meet the basic needs of programmers and is easier to use.


  • co/include
    Header files of libco.

  • co/src
    Source files of libco.

  • co/test
    Some test code, each .cc file will be compiled into a separate test program.

  • co/unitest
    Some unit test code, each .cc file corresponds to a different test unit, and all code is compiled into a single test program.

  • co/gen
    A code generation tool automatically generates rpc framework code according to the proto file.



Xmake is recommended for compiling the CO project.

  • Compiler

  • Install xmake

    For windows, mac and debian/ubuntu, you can directly go to the xmake release page to download the installation package. For other systems, please refer to xmake's installation instructions.

    Xmake disables compilation as root by default on linux. ruki says it is not safe. You can add the following line to ~/.bashrc to enable root compilation:

    export XMAKE_ROOT=y
  • Quick start

    # All commands are executed in the root directory of co (the same below)
    xmake       # build libco and gen by default
    xmake -a    # build all projects (libco, gen, co/test, co/unitest)
  • Build libco

    xmake build libco      # build libco only
    xmake -b libco         # the same as above
  • Build and run unitest code

    co/unitest is unit test code that verifies the correctness of the functionality of the base library.

    xmake build unitest    # build can be abbreviated as -b
    xmake run unitest -a   # run all unit tests
    xmake r unitest -a     # the same as above
    xmake r unitest -os    # run unit test os
    xmake r unitest -json  # run unit test json
  • Build and run test code

    co/test contains some test code. You can easily add a source file in the co/test directory, and then execute xmake build xxx to build it.

    xmake build flag             #
    xmake build log              #
    xmake build json             #
    xmake build rapidjson        #
    xmake build rpc              #
    xmake build easy             # so/
    xmake build pingpong         # so/
    xmake r flag -xz             # test flag
    xmake r log                  # test log
    xmake r log -cout            # also log to terminal
    xmake r log -perf            # performance test
    xmake r json                 # test json
    xmake r rapidjson            # test rapidjson
    xmake r rpc                  # start rpc server
    xmake r rpc -c               # start rpc client
    xmake r easy -d xxx          # start web server
    xmake r pingpong             # pingpong server:
    xmake r pingpong ip=::       # pingpong server:   :::9988  (ipv6)
    xmake r pingpong -c ip=::1   # pingpong client -> ::1:9988
  • Build gen

    # It is recommended to put gen in the system directory (e.g. /usr/local/bin/).
    xmake build gen
    gen hello_world.proto

    Proto file format can refer to hello_world.proto.

  • Installation

    # Install header files, libco, gen by default.
    xmake install -o pkg         # package related files to the pkg directory
    xmake i -o pkg               # the same as above
    xmake install -o /usr/local  # install to the /usr/local directory


izhengfan has helped to provide cmake support:

  • Build libco and gen by default.
  • The library files are in the build/lib directory, and the executable files are in the build/bin directory.
  • You can use BUILD_ALL to compile all projects.
  • You can use CMAKE_INSTALL_PREFIX to specify the installation directory.
mkdir build && cd build
cmake ..
make -j8
make install


CO is licensed under the MIT License. It includes code from some other projects, which have their own licenses, see details in

Special thanks

  • The code of co/context is from tbox by ruki, special thanks!
  • The English reference documents of CO are translated by Leedehai (1-10), daidai21 (11-15) and google, special thanks!
  • ruki has helped to improve the xmake compilation scripts, thanks in particular!
  • izhengfan provided cmake compilation scripts, thank you very much!


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