Method open

src/fl/stl/asio/ip/tcp.cpp.hpp:360–412

acceptor::~acceptor() FL_NOEXCEPT { close(); }

error_code acceptor::open(u16 port) {
    close();

#ifdef FL_IS_WIN
    if (!initialize_winsock()) {
        return error_code(errc::unknown, "winsock init failed");
    }
#endif

    int sock = plat_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock < 0) {
        return error_code(errc::unknown, "socket creation failed");
    }

    // SO_REUSEADDR for quick restarts
    int reuse = 1;
    plat_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&reuse,
                    sizeof(reuse));

    struct sockaddr_in addr {};
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    // Bind to loopback for consistent behavior across platforms
    // especially for port 0 (ephemeral port assignment)
    addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

    int ret =
        plat_bind(sock, (struct sockaddr *)&addr, sizeof(addr));
    if (ret != 0) {
        plat_close(sock);
        return error_code(errc::address_in_use, "bind failed");
    }

    // Query actual port if 0 was requested
    if (port == 0) {
        struct sockaddr_in boundAddr {};
        socklen_t addrLen = sizeof(boundAddr);
        if (plat_getsockname(sock, (struct sockaddr *)&boundAddr,
                             &addrLen) != 0) {
            plat_close(sock);
            return error_code(errc::unknown, "getsockname failed - cannot resolve ephemeral port");
        }
        port = ntohs(boundAddr.sin_port);
    }

    mFd = sock;
    mPort = port;

    // Non-blocking — blocking is never appropriate on embedded
    set_nonblocking(mFd, true);

    return error_code();
}

error_code acceptor::listen(int backlog) {
    if (mFd == -1) {