Returns available TCP Port in Objective-C / Cocoa

availableTcpPort.m

- (int) availableTcpPort
{
    struct sockaddr_in addr;
    socklen_t len = sizeof(addr);
    addr.sin_port = 0;
    inet_aton("0.0.0.0", &addr.sin_addr);
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        perror("socket()");
        return -1;
    }
    if (bind(sock, (struct sockaddr*) &addr, sizeof(addr)) != 0) {
        perror("bind()");
        return -1;
    }
    if (getsockname(sock, (struct sockaddr*) &addr, &len) != 0) {
        perror("getsockname()");
        return -1;
    }
    return (addr.sin_port);
}