Function TCPConnect

chatlib.c:65–109

Create a TCP socket and connect it to the specified address. * On success the socket descriptor is returned, otherwise -1. * * If 'nonblock' is non-zero, the socket is put in nonblocking state * and the connect() attempt will not block as well, but the socket * may not be immediately ready for writing. */

 * and the connect() attempt will not block as well, but the socket
 * may not be immediately ready for writing. */
int TCPConnect(char *addr, int port, int nonblock) {
    int s, retval = -1;
    struct addrinfo hints, *servinfo, *p;

    char portstr[6]; /* Max 16 bit number string length. */
    snprintf(portstr,sizeof(portstr),"%d",port);
    memset(&hints,0,sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    if (getaddrinfo(addr,portstr,&hints,&servinfo) != 0) return -1;

    for (p = servinfo; p != NULL; p = p->ai_next) {
        /* Try to create the socket and to connect it.
         * If we fail in the socket() call, or on connect(), we retry with
         * the next entry in servinfo. */
        if ((s = socket(p->ai_family,p->ai_socktype,p->ai_protocol)) == -1)
            continue;

        /* Put in non blocking state if needed. */
        if (nonblock && socketSetNonBlockNoDelay(s) == -1) {
            close(s);
            break;
        }

        /* Try to connect. */
        if (connect(s,p->ai_addr,p->ai_addrlen) == -1) {
            /* If the socket is non-blocking, it is ok for connect() to
             * return an EINPROGRESS error here. */
            if (errno == EINPROGRESS && nonblock) return s;

            /* Otherwise it's an error. */
            close(s);
            break;
        }

        /* If we ended an iteration of the for loop without errors, we
         * have a connected socket. Let's return to the caller. */
        retval = s;
        break;
    }

    freeaddrinfo(servinfo);
    return retval; /* Will be -1 if no connection succeded. */
}

/* If the listening socket signaled there is a new connection ready to
 * be accepted, we accept(2) it and return -1 on error or the new client