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POC++ Sockets recv() syscall returning -1
 

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  1. POC++ Sockets recv() syscall returning -1
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    <p>I'm currently having a problem passing messages between a server and client. As far as I know, I am properly following best practices for socket programming outlined by <a href="http://beej.us/guide/bgnet/" rel="nofollow">Beej's Socket Programming Tutorial</a>.</p> <p>When I run the two processes, the recv() syscall returns -1 (an error), rather than the number of bytes received. Also when trying to output the buf, there are a bunch of gobbledygook characters. Which makes sense, because of the error.</p> <p>I'm wondering if someone could steer me in the right direction as to why I am having issues with recv()? The following are relevant code snippets.</p> <p>Server:</p> <pre><code>struct sockaddr_storage their_addr; socklen_t addr_size; int sockfd, newfd, byte_count, status; char buf[512]; struct addrinfo hints, *res; // first, load up address structs with getaddrinfo(): memset(&amp;hints, 0, sizeof hints); hints.ai_family = PF_INET; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = IPPROTO_TCP; // get address info, print stuff if error if((status = getaddrinfo("nunki.usc.edu", "21957", &amp;hints, &amp;res)) !=0){ fprintf(stderr, "getaddrinfo error: %s\n", gai_strerror(status)); exit(1); } // make a socket: if((sockfd = socket(res-&gt;ai_family, res-&gt;ai_socktype, res-&gt;ai_protocol)) == -1){ cout &lt;&lt; "socket fail" &lt;&lt; endl; } // bind the socket to the port bind(sockfd, res-&gt;ai_addr, res-&gt;ai_addrlen); // required output cout &lt;&lt; "Phase1: Login server has TCP port number " &lt;&lt; "21957 " &lt;&lt; "and IP address " &lt;&lt; getIPfromHost("nunki.usc.edu") &lt;&lt; endl; // listen for incoming connections listen(sockfd, 10); cout &lt;&lt; "after listen" &lt;&lt; endl; // halt until receipt addr_size = sizeof(their_addr); newfd = accept(sockfd, (struct sockaddr *)&amp;their_addr, &amp;addr_size); cout &lt;&lt; "after accept" &lt;&lt; endl; // Now that we're connected, we can receive some data byte_count = recv(sockfd, buf, sizeof buf, 0); printf("recv()'d %d bytes of data in buf\n", byte_count); printf("Msg is %s\n", buf); </code></pre> <p>Client:</p> <pre><code>struct addrinfo hints, *res; int sockfd; // first, load up address structs with getaddrinfo(): memset(&amp;hints, 0, sizeof hints); hints.ai_family = AF_INET; hints.ai_socktype = SOCK_STREAM; getaddrinfo("nunki.usc.edu", "21957", &amp;hints, &amp;res); // make a socket: if((sockfd = socket(res-&gt;ai_family, res-&gt;ai_socktype, res-&gt;ai_protocol)) == -1){ cout &lt;&lt; "socket fail" &lt;&lt; endl; } // attempt connection to port if(connect(sockfd, res-&gt;ai_addr, res-&gt;ai_addrlen) == -1){ cout &lt;&lt; "connect fail" &lt;&lt; endl; } // send message to server cout &lt;&lt; "sockfd " &lt;&lt; sockfd &lt;&lt; endl; int byte_count = send(sockfd, "Hello", 5, 0); cout &lt;&lt; byte_count &lt;&lt; endl; </code></pre> <p>The following is the output for Server:</p> <pre><code>Phase1: Login server has TCP port number 21957 and IP address 68.181.201.3 after listen after accept recv()'d -1 bytes of data in buf Msg is ÿhÿ?sÈ Glæ </code></pre> <p>The following is the output for Client:</p> <pre><code>sockfd 4 5 </code></pre>
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