在第 67 行我有代码
void session::read_handler(const boost::system::error_code& ec, std::size_t bytes_transferred)
{
std::cout<<bytes_transferred<<std::endl;
}
只要服务器在 session 类中接收到数据包,就应该轮询它,但由于某种原因,该函数从未被调用。 io_service.run();
在 int main()
中为 read_handler()
调用.该代码基本上是 Boost 网站上的异步服务器示例,具有我添加的功能。这是代码。
#include <cstdlib>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
using boost::asio::ip::tcp;
class session
{
public:
session(boost::asio::io_service& io_service)
: socket_(io_service)
{
}
tcp::socket& socket()
{
return socket_;
}
void start()
{
socket_.async_read_some(boost::asio::buffer(data_, max_length),
boost::bind(&session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
void read_handler(const boost::system::error_code& ec, std::size_t bytes_transferred);
private:
void handle_read(const boost::system::error_code& error,
size_t bytes_transferred)
{
if (!error)
{
boost::asio::async_write(socket_,
boost::asio::buffer(data_, bytes_transferred),
boost::bind(&session::handle_write, this,
boost::asio::placeholders::error));
}
else
{
delete this;
}
}
void handle_write(const boost::system::error_code& error)
{
if (!error)
{
socket_.async_read_some(boost::asio::buffer(data_, max_length),
boost::bind(&session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
}
else
{
delete this;
}
}
tcp::socket socket_;
enum { max_length = 1024 };
char data_[max_length];
};
void session::read_handler(const boost::system::error_code& ec, std::size_t bytes_transferred)
{
std::cout<<bytes_transferred<<std::endl;
}
class server
{
public:
server(boost::asio::io_service& io_service, short port)
: io_service_(io_service),
acceptor_(io_service, tcp::endpoint(tcp::v4(), port))
{
start_accept();
}
private:
void start_accept()
{
session* new_session = new session(io_service_);
acceptor_.async_accept(new_session->socket(),
boost::bind(&server::handle_accept, this, new_session,
boost::asio::placeholders::error));
}
void handle_accept(session* new_session,
const boost::system::error_code& error)
{
if (!error)
{
new_session->start();
}
else
{
delete new_session;
}
start_accept();
}
boost::asio::io_service& io_service_;
tcp::acceptor acceptor_;
};
int main()
{
try
{
boost::asio::io_service io_service;
server s(io_service, 4000);
io_service.run();
}
catch (std::exception& e)
{
std::cerr << "Exception: " << e.what() << "\n";
}
return 0;
}
最佳答案
session::read_handler(...) 未设置为处理程序。
handle_accept() 被调用是因为它被设置为处理程序:
acceptor_.async_accept(new_session->socket(),
boost::bind(&server::handle_accept, this, new_session,
boost::asio::placeholders::error));
handle_read(...) 被调用是因为它被设置为处理程序:
socket_.async_read_some(boost::asio::buffer(data_, max_length),
boost::bind(&session::handle_read, this,
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred));
handle_write(...) 相同 - 由 handle_read 函数设置。
但是没有设置read_handler。请改用 handle_read。或者从 handle_read 调用 read_handler。
void handle_read(const boost::system::error_code& error,
size_t bytes_transferred)
{
if (!error)
{
std::cout<<bytes_transferred<<std::endl; // try this.
read_handler(error, bytes_transferred); // OR this.
boost::asio::async_write(socket_,
boost::asio::buffer(data_, bytes_transferred),
boost::bind(&session::handle_write, this,
boost::asio::placeholders::error));
}
else
{
delete this;
}
}
关于C++:BOOST-ASIO read_handler() 没有按预期工作?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15967257/