I'm starting using Boost::Asio. I tried to write a simple class to
send and receive asynchronously UDP datagrams, following the
boost::asio tutorial. The class compiles fine, but it's not working
and comes out with an exception about a mutex (which shouldn't be
involved I guess). Basically there are two methods: one starts an
async_receive_from and the other send packets asynchronously. I first
start the receiver, then I try to send a packet to localhost
(127.0.0.1). But nothing happens. Here is the code, maybe you may
know what's wrong.
With the following class
the header:
namespace msgSrv {
class endPoint {
public:
asio::ip::udp::endpoint ep;
endPoint(std::string ip, int port);
};
class msgSrv {
private:
asio::ip::udp::socket *asioSocket;
asio::io_service *asioIoService;
int listenPort;
boost::array rcvBuff;
asio::ip::udp::endpoint lastRcvdPcktEndp;
char * sbuff;
public:
boost::condition_variable cond;
boost::mutex mut;
msgSrv(int listenPort);
virtual ~msgSrv();
void start();
void pckRcvd(const asio::error_code& error, std::size_t
bytes_transferred);
void sendTo(const char* buff, int len, endPoint ep);
void sendHnd(const asio::error_code& error, std::size_t
bytes_transferred);
};
}
the .cpp
#include "msgSrv.h"
namespace msgSrv {
endPoint::endPoint(const std::string ip, int port) {
asio::ip::address addr = asio::ip::address::from_string(ip);
ep = asio::ip::udp::endpoint(addr, port);
}
msgSrv::msgSrv(int listenPort) {
// TODO Auto-generated constructor stub
this->listenPort = listenPort;
try {
asioIoService = new asio::io_service();
asioSocket = new asio::ip::udp::socket(*asioIoService,
asio::ip::udp::endpoint(asio::ip::udp::v4(),
listenPort)); //new asio::ip::udp::socket_(*asioIoService,
udp::endpoint(udp::v4(), listenPort));
} catch (std::exception &e) {
std::cerr << "Error initializing ioservice or socket:" <<
e.what();
}
asioIoService->run();
}
msgSrv::~msgSrv() {
// TODO Auto-generated destructor stub
delete asioIoService;
delete asioSocket;
}
void msgSrv::start() {
asioSocket->async_receive_from(asio::buffer(rcvBuff),
lastRcvdPcktEndp,
boost::bind(&msgSrv::pckRcvd, this,
asio::placeholders::error,
asio::placeholders::bytes_transferred));
}
void msgSrv::pckRcvd(const asio::error_code& error,
std::size_t bytes_transferred) {
std::cout << "Rcvd! " << lastRcvdPcktEndp.address().to_string() <<
":"
<< lastRcvdPcktEndp.port() << "\n";
}
void msgSrv::sendTo(const char* buff, int len, endPoint ep) {
sbuff = new char[len];
mempcpy(sbuff, buff, len);
asioSocket->async_send_to(asio::buffer(sbuff, len), ep.ep,
boost::bind(
&msgSrv::sendHnd, this, asio::placeholders::error,
asio::placeholders::bytes_transferred));
}
void msgSrv::sendHnd(const asio::error_code& error,
std::size_t bytes_transferred) {
std::cout << "Snt!\n";
delete sbuff;
}
}
and the following "main" file:
int main()
{
msgSrv::msgSrv aa(4450);
aa.start();
msgSrv::endPoint ep("127.0.0.1", 4450);
std::string a("Prova!");
int len = a.length();
aa.sendTo(a.c_str(), len, ep);
std::cout << "sent...\n";
std::cout << "notified...\n";
}
all I get is:
terminate called after throwing an instance of 'asio::system_error'
what(): mutex: Invalid argument
sent...
notified...
What's wrong?? I tried even to put a while(1) in the main, to see if
something happens... I even tried to put a condition in the main that
is unlocked by the receive handler... all remains locked... So what???
No idea!
