Release Notes and New Features of the ‘co’ C++ Coroutine Library

The "co" C++ coroutine library has been updated; the source code is available at https://github.com/idealvin/co with Chinese and English reference documentation hosted on GitHub and Gitee.

New features include the xrepo installer, VCPKG support, a defer utility similar to Go's defer, a channel implementation, and a waitgroup analogous to Go's sync.WaitGroup. Example usages are:

sh
xrepo install -f "openssl=true,libcurl=true" co

sh
vcpkg install co:x64-windows
# http & ssl support
vcpkg install co[libcurl,openssl]:x64-windows

cpp
#include "co/defer.h"
Timer t;
defer(LOG << "time elapse: " << t.us() << "us");

cpp
#include "co/co.h"
DEF_main(argc, argv) {
    co::Chan<int> ch;
    go([ch]() { ch << 7; });
    int v = 0;
    ch >> v;
    LOG << "v: " << v;
    return 0;
}

cpp
#include "co/co.h"
DEF_main(argc, argv) {
    FLG_cout = true;
    co::WaitGroup wg;
    wg.add(8);
    for (int i = 0; i < 8; ++i) {
        go([wg]() {
            LOG << "co: " << co::coroutine_id();
            wg.done();
        });
    }
    wg.wait();
    return 0;
}

Additional API changes add void flag::init(const fastring& path);, rename the global Closure to co::Closure, improve co::Event, co::Mutex, and co::Pool to support copy construction and value capture in lambdas, and make co::close() callable from any context. Partial support for MinGW is added, though coroutine features are not yet functional on that platform.

Bug fixes address a file‑read/write issue when handling data larger than 4 GB in fs::file, correct error messages for HTTP client connection timeouts, and resolve a linking problem reported in issue #165.