我开始练习使用boost asio&提升野兽来开发自己的基本服务器和连接类。最近我遇到了bad_weak_ptr异常,我无法弄清楚如何管理问题。这是代码:
class server : public boost::asio::io_context::service
{
tcp::endpoint endpoint{ boost::asio::ip::address_v6::any(), 7654 };
tcp::acceptor acceptor;
boost::asio::strand<boost::asio::io_context::executor_type> strand;
std::vector<std::weak_ptr<tcp_connection_ui>> connections;
public:
static const boost::asio::execution_context::id id;
explicit tcp_server_ui(boost::asio::io_context& ioc)
: boost::asio::io_context::service{ ioc }
, acceptor{ ioc, endpoint }
, strand{ ioc.get_executor() }
{
}
void run()
{
boost::asio::post(strand, [this] {start_accept(); });
}
void start_accept()
{
tcp::socket socket{ acceptor.get_io_context() };
tcp_connection_ui::pointer new_connection =
tcp_connection_ui::create(std::move(socket));
connections.push_back(new_connection);
acceptor.async_accept(new_connection->web_socket().next_layer(),
boost::asio::bind_executor(strand, std::bind(
&tcp_server_ui::handle_accept,
this, new_connection, std::placeholders::_1)));
}
void handle_accept(tcp_connection_ui::pointer new_connection,
boost::system::error_code ec)
{
if (!ec) {
new_connection->run();
}
start_accept();
}
void broadcast(std::string&& msg)
{
std::cout << '+' << std::endl;
if (connections.empty())
return;
for (auto const & x : connections)
x.lock()->enqueue_message(std::move(msg));
}
};
还有代码停止运行的地方:
class tcp_connection_ui : std::enable_shared_from_this<tcp_connection_ui>
{
public:
using pointer = std::shared_ptr<tcp_connection_ui>;
static pointer create(tcp::socket socket)
{
return std::make_shared<tcp_connection_ui>(tcp_connection_ui{ std::move(socket) });
}
void run()
{
ws.async_accept(boost::asio::bind_executor(strand, std::bind(
&tcp_connection_ui::on_accept, shared_from_this(),
std::placeholders::_1)));
} .../};
如果客户端尝试在server :: handle_accept中连接值shared_from_this等于_Wptr = empty。我认为我在理解io_context :: service和/或shared_from_this功能方面遇到了一些麻烦。任何帮助将不胜感激。
答案 0 :(得分:2)
必须公开继承基类:
class tcp_connection_ui : public std::enable_shared_from_this<tcp_connection_ui>
否则,make_shared
或shared_ptr
将不会注意到它,并且随后无法初始化&#34;隐藏&#34;的weak_ptr