NAME

       nng_tcp - TCP/IP transport

SYNOPSIS

           #include <nng/transport/tcp/tcp.h>

           int nng_tcp_register(void);

DESCRIPTION

       The tcp transport provides communication support between sockets across a TCP/IP network.
       Both IPv4 and IPv6 are supported when the underlying platform also supports it.

   Registration
       This transport is generally built-in to the core of NNG, so no extra steps to use it
       should be necessary.

   URI Format
       This transport uses URIs using the scheme tcp://, followed by an IP address or hostname,
       followed by a colon and finally a TCP port number. For example, to contact port 80 on the
       localhost either of the following URIs could be used: tcp://127.0.0.1:80 or
       tcp://localhost:80.

       A URI may be restricted to IPv6 using the scheme tcp6://, and may be restricted to IPv4
       using the scheme tcp4://.

           Note
           Specifying tcp6:// may not prevent IPv4 hosts from being used with IPv4-in-IPv6
           addresses, particularly when using a wildcard hostname with listeners. The details of
           this varies across operating systems.

           Note
           Both tcp6:// and tcp4:// are specific to NNG, and might not be understood by other
           implementations.

           Tip
           We recommend using either numeric IP addresses, or names that are specific to either
           IPv4 or IPv6 to prevent confusion and surprises.

       When specifying IPv6 addresses, the address must be enclosed in square brackets ([]) to
       avoid confusion with the final colon separating the port.

       For example, the same port 80 on the IPv6 loopback address (::1) would be specified as
       tcp://[::1]:80.

       The special value of 0 (INADDR_ANY) can be used for a listener to indicate that it should
       listen on all interfaces on the host. A short-hand for this form is to either omit the
       address, or specify the asterisk (*) character. For example, the following three URIs are
       all equivalent, and could be used to listen to port 9999 on the host:

        1. tcp://0.0.0.0:9999

        2. tcp://*:9999

        3. tcp://:9999

       The entire URI must be less than NNG_MAXADDRLEN bytes long.

   Socket Address
       When using an nng_sockaddr structure, the actual structure is either of type
       nng_sockaddr_in (for IPv4) or nng_sockaddr_in6 (for IPv6).

   Transport Options
       The following transport options are supported by this transport, where supported by the
       underlying platform.

       •   NNG_OPT_LOCADDR

       •   NNG_OPT_REMADDR

       •   NNG_OPT_TCP_KEEPALIVE

       •   NNG_OPT_TCP_NODELAY

       •   NNG_OPT_URL

SEE ALSO

       nng_options(5), nng_sockaddr(5), nng_sockaddr_in(5), nng_sockaddr_in6(5),
       nng_tcp_options(5), nng(7)

                                            2024-12-27                                 NNG_TCP(7)