tcp nonblocking not working - c++

Question

I have a tcp server and 2 clients that want to connect to it. The way this clients will connect is that 1 of them, lets call it client1 will be all the time connected sending data and the other, client2, will eventually connect, send small amount of data and disconnect. I set O_NONBLOCK option on. The behaviour I experience is that the client that is continuosly sending data,on server side, receives one message and wait for the next connection... Here is what i tried so far(The code is the while where in any moment the client2 wants to connect and send data and disconnect):
fcntl(sockfd, F_SETFL, O_NONBLOCK);
if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
error("ERROR on binding");
listen(sockfd, 5);
clilen = sizeof(cli_addr);
int flag = 0;
do {
newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
if(newsockfd > 0){
//Sockets Layer Call: inet_ntop()
inet_ntop(AF_INET6, &(cli_addr.sin6_addr),client_addr_ipv6, 100);
printf("Incoming connection from client having IPv6 address: %s\n",client_addr_ipv6);
n = recv(newsockfd, buffer, 49,0);
if(n > 0){
send_data(argv[1],argv[2],argv[3],argv[4],argv[5],argv[6],buffer);
memset(buffer,0,sizeof(buffer));
}
}
newsockfd2 = accept(sockfd, (struct sockaddr *) &cli_addr2, &clilen);
//Sockets Layer Call: inet_ntop()
if(newsockfd2 > 0){
inet_ntop(AF_INET6, &(cli_addr2.sin6_addr),client_addr_ipv6, 100);
printf("Incoming connection from client having IPv6 address: %s\n",client_addr_ipv6);
n2= recv(newsockfd2, buffer, 49, 0);
if(n2 > 0){
send_data(argv[1],argv[2],argv[3],argv[4],argv[5],argv[6],buffer);
memset(buffer,0,sizeof(buffer));
}
}
}while(!flag);
I also tried adding the option inside of the while and setting nonblocking on newsockfd and newsockfd2but same result.
What am I doing wrong? thanks ! :D

Answer 1

When a new socket is retuned from accept, you must create a new thread with this socket so that one-to-one communication will be handled in this thread. The socked doesn't have to ne non-blocking.