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#include <iostream>
#include <boost/array.hpp>
#include <boost/asio.hpp>
using boost::asio::ip::tcp;
int main(int argc, char* argv[])
{
try
{
// the user should specify the server - the 2nd argument
if (argc != 2)
{
std::cerr << "Usage: client " << std::endl;
return 1;
}
// Any program that uses asio need to have at least one io_service object
boost::asio::io_service io_service;
// Convert the server name that was specified as a parameter to the application, to a TCP endpoint.
// To do this, we use an ip::tcp::resolver object.
tcp::resolver resolver(io_service);
// A resolver takes a query object and turns it into a list of endpoints.
// We construct a query using the name of the server, specified in argv[1],
// and the name of the service, in this case "daytime".
tcp::resolver::query query(argv[1], "daytime");
// The list of endpoints is returned using an iterator of type ip::tcp::resolver::iterator.
// A default constructed ip::tcp::resolver::iterator object can be used as an end iterator.
tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);
// Now we create and connect the socket.
// The list of endpoints obtained above may contain both IPv4 and IPv6 endpoints,
// so we need to try each of them until we find one that works.
// This keeps the client program independent of a specific IP version.
// The boost::asio::connect() function does this for us automatically.
tcp::socket socket(io_service);
boost::asio::connect(socket, endpoint_iterator);
// The connection is open. All we need to do now is read the response from the daytime service.
for (;;)
{
// We use a boost::array to hold the received data.
boost::array <char , 1> buf;
boost::system::error_code error;
// The boost::asio::buffer() function automatically determines
// the size of the array to help prevent buffer overruns.
size_t len = socket.read_some(boost::asio::buffer(buf), error);
// When the server closes the connection,
// the ip::tcp::socket::read_some() function will exit with the boost::asio::error::eof error,
// which is how we know to exit the loop.
if (error == boost::asio::error::eof)
break; // Connection closed cleanly by peer.
else if (error)
throw boost::system::system_error(error); // Some other error.
std::cout.write(buf.data(), len);
}
}
// handle any exceptions that may have been thrown.
catch (std::exception& e)
{
std::cerr << e.what() << std::endl;
}
return 0;
}
しかし、このプログラムをコンパイルすると、次のエラーが発生します。このエラーを取り除くのを手伝ってください。 $ g ++ -lpthread syn_client.cpp -o syn_client.out -lboost_system /usr/bin/ld：/tmp/ccozoiHn.o：未定義のシンボル 'pthread_create @@ GLIBC_2.2.5' /lib/x86_64-linux- GNU/libpthread.so.0：エラーがシンボルを追加：エラー：DSOは、コマンドラインから collect2はを逃しldがboost.asio cppのserver-clientプログラム