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copied!<p>For whatever reason, I was not able to get a non blocking solution using "select" working. (But thank you both for your helpful responses.) I ended up using one of the socket options that let me specify a shorter timeout.</p> <pre><code>setsockopt(clientsock_fd, IPPROTO_TCP, TCP_CONNECTIONTIMEOUT, &timeout, sizeof(timeout)); </code></pre> <p>In the interest of completeness, this is what I ended up with (error checking removed for clarity):</p> <pre><code>-(void)connect_to_control:(NSTimer*) timer </code></pre> <p>{</p> <pre><code>clientsock_fd = socket(AF_INET, SOCK_STREAM, 0); int no_delay = 1; int result = setsockopt(clientsock_fd, IPPROTO_TCP, TCP_NODELAY, &no_delay, 4); // *** Set timeout value to stop hanging *** struct timeval timeout; timeout.tv_sec =1; timeout.tv_usec =0; result = setsockopt(clientsock_fd, IPPROTO_TCP, TCP_CONNECTIONTIMEOUT, &timeout, sizeof(timeout)); struct sockaddr_in the_addr; memset((void *)&the_addr, 0, sizeof(the_addr)); the_addr.sin_family = AF_INET; the_addr.sin_port = htons(25556); const char* server_addr = "192.168.3.22"; unsigned long ip_addr = inet_addr(server_addr); the_addr.sin_addr.s_addr = ip_addr; int err_test = connect(clientsock_fd, (const struct sockaddr*)&the_addr, sizeof(the_addr)); // hangs here when address can't be reached! </code></pre> <p><strong>NOTE:</strong> I had to upgrade to OS 3.0 to use <code>TCP_CONNECTIONTIMEOUT</code>. TCP_CONNECTIONTIMEOUT is defined in "tcp.h" the OS 3.0 SDK headers but not in OS 2.1. It is not defined in the simulator headers, only the device headers.</p>

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