Io_context error in Boost Library

Question

I'm trying to build a chat room using by Boost Libraries. But when I'm trying to use asio::io_context, the compiler says:

io_context is not an member of asio.

I built Boost 4 times and I thought maybe the problem was due to an installation failure on my part, but it doesn't seem to be.

#include <ctime>
#include <iostream>
#include <string>
#include <boost/bind.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/asio.hpp>

using boost::asio::ip::tcp;

std::string make_daytime_string()
{
    using namespace std; // For time_t, time and ctime;
    time_t now = time(0);
    return ctime(&now);
}

class tcp_connection
    : public boost::enable_shared_from_this<tcp_connection>
{
public:
    typedef boost::shared_ptr<tcp_connection> pointer;

    static pointer create(boost::asio::io_context& io_context)
    {
        return pointer(new tcp_connection(io_context));
    }

    tcp::socket& socket()
    {
        return socket_;
    }

    void start()
    {
        message_ = make_daytime_string();

        boost::asio::async_write(socket_, boost::asio::buffer(message_),
            boost::bind(&tcp_connection::handle_write, shared_from_this(),
                boost::asio::placeholders::error,
                boost::asio::placeholders::bytes_transferred));
    }

private:
    tcp_connection(boost::asio::io_context& io_context)
        : socket_(io_context)
    {
    }

    void handle_write(const boost::system::error_code& /*error*/,
        size_t /*bytes_transferred*/)
    {
    }

    tcp::socket socket_;
    std::string message_;
};

class tcp_server
{
public:
    tcp_server(boost::asio::io_context& io_context) //error
        : acceptor_(io_context, tcp::endpoint(tcp::v4(), 13)) //error
    {
        start_accept();
    }

Answer 1

Things changed in Boost 1.66:

The release notes show the renamed/changed interfaces:

Boost.Asio now provides the interfaces and functionality specified by the "C++ Extensions for Networking" Technical Specification. In addition to access via the usual Boost.Asio header files, this functionality may be accessed through special headers that correspond to the header files defined in the TS. These are listed in the table below: