udp(3tnm)

NAME

Tnm::udp - Send and receive UDP datagrams.

DESCRIPTION

The Tnm::udp command allows to send and receive datagrams using the User Datagram Protocol (UDP) (RFC 768).

UDP COMMAND

Tnm::udp open [port]

The Tnm::udp open command opens a UDP datagram socket and returns a handle. The socket is bound to a given port number or name. An unused port number is used if the port argument is missing.

Tnm::udp connect host port

The Tnm::udp connect command opens a UDP datagram socket and connects it to a port on a remote host. A connected UDP socket only allows to send messages to a single destination. This usually allows to shorten the code since there is no need to specify the destination address for each Tnm::udp send command on a connected UDP socket. The command returns a udp handle.

Tnm::udp send handle [host port] message

The Tnm::udp send command sends a datagram containing message to the destination specified by host and port. The host and port arguments may not be used if the UDP handle is already connected to a transport endpoint. If the UDP handle is not connected, you must use these optional arguments to specify the destination of the datagram.

Tnm::udp receive handle

The Tnm::udp receive command receives a datagram from the UDP socket associated with handle. This command blocks until a datagram is ready to be received. In most cases, it might be a good idea to check for pending datagrams using the Tnm::udp bind command.

Tnm::udp close handle

The Tnm::udp close command closes the UDP socket associated with handle.

Tnm::udp bind handle readable [script]

Tnm::udp bind handle writable [script]

The Tnm::udp bind command allows to bind scripts to a UDP handle. A script is evaluated once the UDP handle becomes either readable or writable, depending on the third argument of the Tnm::udp bind command. The script currently bound to a UDP handle can be retrieved by calling the udp bind command without a script argument. Bindings are removed by binding an empty string.

Tnm::udp info [handle]

The Tnm::udp info command without the handle argument returns a list of all existing UDP handles. Information about the state of a UDP handle can be obtained by supplying a valid UDP handle. The result is a list containing the source IP address, the source port, the destination IP address and the destination port.

SEE ALSO

scotty(1), Tnm(n), Tcl(n)

AUTHORS

Juergen Schoenwaelder <[email protected]>