UDT Tutorial

Hello World!

In this section we will introduce the simplest UDT program that can transfer data in high performance.

This simple "Hello World!" example includes a server program and a client program just like any socket programming tutorial. These are the simpler version of the appserver and appclient examples in ./app directory.

To compile, use gcc -o server server.cpp -I<udt.h location> -L<libudt.so location> -ludt -lstdc++ -lpthread. For more details, please refer to the Makefile in ./app directory.

UDT server example

#include <iostream>
#include <udt.h>
#include <arpa/inet.h>

using namespace std;

using namespace UDT;

int main()
{
UDTSOCKET serv = UDT::socket(AF_INET, SOCK_STREAM, 0);

sockaddr_in my_addr;
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(9000);
my_addr.sin_addr.s_addr = INADDR_ANY;
memset(&(my_addr.sin_zero), '\0', 8);

if (UDT::ERROR == UDT::bind(serv, (sockaddr*)&my_addr, sizeof(my_addr)))
{
   cout << "bind: " << UDT::getlasterror().getErrorMessage();
   return 0;
}

CUDT::listen(serv, 10);

int namelen;
sockaddr_in their_addr;

UDTSOCKET recver = UDT::accept(serv, (sockaddr*)&their_addr, &namelen);

char ip[16];
cout << "new connection: " << inet_ntoa(their_addr.sin_addr) << ":" << ntohs(their_addr.sin_port) << endl;

char data[100];

if (UDT::ERROR == UDT::recv(recver, data, 100, 0))
{
   cout << "recv:" << UDT::getlasterror().getErrorMessage() << endl;
   return 0;
}

cout << data << endl;

CUDT::close(recver);
CUDT::close(serv);

return 1;
}

This simple server tries to bind itself at port 9000. If succeed, it listens at port 9000 and accepts a client and then reads a string.

UDT client example

#include <iostream>
#include <udt.h>
#include <arpa/inet.h>

using namespace std;
using namespace UDT;

int main()
{
UDTSOCKET client = UDT::socket(AF_INET, SOCK_STREAM, 0);

sockaddr_in serv_addr;
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(9000);
inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr);

memset(&(serv_addr.sin_zero), '\0', 8);

// connect to the server, implict bind
if (UDT::ERROR == UDT::connect(client, (sockaddr*)&serv_addr, sizeof(serv_addr)))
{
   cout << "connect: " << UDT::getlasterror().getErrorMessage();
   return 0;
}

char* hello = "hello world!\n";
if (UDT::ERROR == UDT::send(client, hello, strlen(hello) + 1, 0))
{
   cout << "send: " << UDT::getlasterror().getErrorMessage();
   return 0;
}

UDT::close(client);

return 1;
}

The client side connects to the local address (127.0.0.1) at port 9000, and sends a "hello world!" message.