#include <boost/asio.hpp>#include <iostream>using namespace std;using namespace boost::asio;void client(io_service &ios){    try    {        cout << "client start." << endl;        ip::tcp::socket sock(ios);        ip::tcp::endpoint ep(ip::address::from_string("127.0.0.1"),6688);        sock.connect(ep);        vector<char> str(100,0);        sock.read_some(buffer(str));        cout << "receive from " << sock.remote_endpoint().address();        cout << &str[0] << endl;    }    catch (std::exception& e)    {        cout << e.what() << endl;    }}void print(const boost::system::error_code&){    cout << "test wait..." << endl;}int main(){    io_service ios;    deadline_timer at(ios, boost::posix_time::seconds(5));    at.async_wait(print);    cout << "it show before at exired" <<endl;    ios.run();    return 0;}