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The gen_udp module is an interface to User Datagram Protocol (UDP).
The possible {error, Reason} results are described in the inet manual page.
close(Socket) -> ok | {error, Reason}
Types:
Socket = Reason = term()
Removes the Socket created with open/1 or open/2.
controlling_process(Socket,NewOwner) ->
Types:
Socket = term()
NewOwner = pid()
The process associated with a Socket is changed to NewOwner.
The NewOwner will receive all subsequent data.
open(Port) -> {ok, Socket } | { error, Reason }
open(Port,Options) -> {ok, Socket } | { error, Reason }
Types:
Port = integer(0..65535)
Options = list()
Socket = term()
Reason = term()
Associates a UDP port number (Port) with the calling process. It returns
{ok, Socket}, or {error, Reason}. The returned Socket is used to
send packets from this port with the send/4 function. Options is a list of options
associated with this port.
When UDP packets arrive at the opened Port they will be delivered as messages of the type
{udp, Socket, IP, InPortNo, Packet}. Note that
arriving UDP packets that are longer than the receive buffer
option specifies might be truncated without warning.
IP and InPortNo define the address
from which Packet came. Packet is a list of bytes if the
option list was specified. Packet is a binary if the option binary was
specified.
The available options are:
list
Packet is delivered as a list.
binary
Packet is delivered as a binary.
{ip,IPAddress}
{fd,Fd}
gen_udp, use this option to pass in the file descriptor for it
and create a Socket for it.
inet6
inet
inet options
inet options available are described in the
setopts/2 function
in the inet manual page. Default value for the receive
buffer option is {recbuf, 8192}.
If you set Port to 0, the underlying Operating System assigns a free UDP port. (You can find out which port by calling inet:port(Socket).)
If any of the following functions are called with a Socket that was not opened by
the calling process, they will return {error,not_owner}.
The ownership of a Socket can be transferred to another process
with controlling_process/2.
recv(Socket, Length) -> {ok,{Address, Port, Packet}} | {error, Reason}
recv(Socket, Length, Timeout)
Types:
Socket = socket()
Address = { integer(), integer(), integer(), integer()}
Port = integer(0..65535)
Length = integer()
Packet = list() | binary()
Timeout = integer()
Reason = atom()
This function receives a packet from a socket in passive mode.
The optional Timeout parameter specifies a timeout in
milliseconds. The default value is infinity.
send(S,Address,Port,Packet) -> ok | {error, Reason}
Types:
Address = { integer(), integer(), integer(), integer()}
| atom() | string()
Port = integer(0..65535)
Packet = [byte()] | binary()
Reason = term()
Sends Packet to the specified address (address, port). It
returns ok, or {error, Reason}. Address can be an
IP address expressed as a tuple, for example {192, 0, 0, 1}. It can also be a host name expressed as an atom or a string, for example 'somehost.some.domain'.
Port is an integer, and Packet is either a list of bytes or
a binary.