Re: [Boost-users] [boost-user][asio]How can i limit tcpserver's connection count?

Subject: Re: [Boost-users] [boost-user][asio]How can i limit tcpserver's connection count?
From: Viatcheslav.Sysoltsev_at_[hidden]
Date: 2011-03-15 09:19:50

On Tue, 15 Mar 2011 13:32:31 +0100, rhapsodyn <rhapsodyn_at_[hidden]> wrote:

> here‘s the code
>
> server：
> class tcp_server
> {
> public:
>     tcp_server(boost::asio::io_service& io_service)
>         : acceptor_(io_service),limit(0)
>     {
>         tcp::endpoint endpoint(tcp::v4(), 10000);
>         acceptor_.open(endpoint.protocol());
>         acceptor_.bind(endpoint);
>         acceptor_.listen(1);
>         start_accept();
>     }
>
> private:
>     void start_accept()
>     {
>         while(1)
>         {
>             if(limit < 1)
>                 break;
>         }
>
>         tcp::socket* socket = new tcp::socket(acceptor_.io_service());
>         acceptor_.async_accept(*socket,
>             boost::bind(
>                 &tcp_server::handle_accept,
>                 this,
>                 socket,
>                 boost::asio::placeholders::error));
>     }
>
>     void handle_accept(tcp::socket* s, const boost::system::error_code&
> error)
>     {
>         if (!error)
>         {
>             ++limit;
>             start_accept();
>         }
>     }
>
>     tcp::acceptor acceptor_;
>
>     int limit;
> };
>
> client：
> int main(int argc, char* argv[])
> {
>     int i = 0;
>     try
>     {
>         boost::asio::io_service io_service;
>
>         tcp::resolver resolver(io_service);
>         tcp::resolver::query query("127.0.0.1", "10000");
>         tcp::resolver::iterator endpoint_iterator =  
> resolver.resolve(query);
>         tcp::endpoint endpoint = *endpoint_iterator;
>
>         tcp::socket socket(io_service);
>         socket.connect(endpoint);
>
>         while(1)
>         {}
>     }
>     catch (std::exception& e)
>     {
>         std::cerr << e.what() << std::endl;
>     }
>
>     return 0;
> }
>
> I thought i can only launch 1 client, but fact is: i can start two  
> clients
> and the 3rd one just cerr the what(), what happend there? Is there some
> better way to get & limit the "living-connection" of the server?
>

Ummm, not sure, just a thought, the documentation for listen() says:

void listen(
     int backlog = socket_base::max_connections);

backlog
The maximum length of the queue of pending connections.

So one connection accepted, one pending, third rejected - seems all right?  
Maybe you need to call listen(0)?

-- Slava