udp(n) Tnm Tcl Extension udp(n)_________________________________________________________________NAMEudp - Send and receive UDP datagrams.
_________________________________________________________________DESCRIPTION
The udp command allows to send and receive datagrams using
the User Datagram Protocol (UDP) (RFC 768).
UDP COMMANDudp open [port]
The udp open command opens a UDP datagram socket
and returns an udp handle. The socket is bound to
given port number or name. An unused port number
is used if the port argument is missing.
udp connect host port
The udp connect command opens a UDP datagram socket
and connects it to a port on a remote host. A con-
nected 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 des-
tination address for each udp send command on a
connected UDP socket. The command returns a udp
handle.
udp send handle [host port] message
The 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 trans-
port endpoint. If the UDP handle is not connected,
you must use these optional arguments to specify
the destination of the datagram.
udp receive handle
The 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 udp bind command.
udp close handle
The udp close command closes the UDP socket associ-
ated with handle.
udp bind handle readable [script]
udp bind handle writable [script]
The udp bind command allows to bind scripts to a
UDP handle. A script is evaluated once the UDP han-
dle becomes either readable or writable, depending
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udp(n) Tnm Tcl Extension udp(n)
on the third argument of the 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.
udp info [handle]
The udp info command without the handle argument
returns a list of all existing UDP handles. Infor-
mation 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 ALSOscotty(1), Tnm(n), Tcl(n)AUTHORS
Juergen Schoenwaelder <schoenw@cs.utwente.nl>
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