1gen_udp(3) Erlang Module Definition gen_udp(3)
2
6 gen_udp - Interface to UDP sockets.
7
9 This module provides functions for communicating with sockets using the
10 UDP protocol.
11
13 option() =
14 {active, true | false | once | -32768..32767} |
15 {add_membership, {inet:ip_address(), inet:ip_address()}} |
16 {broadcast, boolean()} |
17 {buffer, integer() >= 0} |
18 {deliver, port | term} |
19 {dontroute, boolean()} |
20 {drop_membership, {inet:ip_address(), inet:ip_address()}} |
21 {header, integer() >= 0} |
22 {high_msgq_watermark, integer() >= 1} |
23 {low_msgq_watermark, integer() >= 1} |
24 {mode, list | binary} |
25 list |
26 binary |
27 {multicast_if, inet:ip_address()} |
28 {multicast_loop, boolean()} |
29 {multicast_ttl, integer() >= 0} |
30 {priority, integer() >= 0} |
31 {raw,
32 Protocol :: integer() >= 0,
33 OptionNum :: integer() >= 0,
34 ValueBin :: binary()} |
35 {read_packets, integer() >= 0} |
36 {recbuf, integer() >= 0} |
37 {reuseaddr, boolean()} |
38 {sndbuf, integer() >= 0} |
39 {tos, integer() >= 0} |
40 {ipv6_v6only, boolean()}
41 option_name() =
43 active |
44 broadcast |
45 buffer |
46 deliver |
47 dontroute |
48 header |
49 high_msgq_watermark |
50 low_msgq_watermark |
51 mode |
52 multicast_if |
53 multicast_loop |
54 multicast_ttl |
55 priority |
56 {raw,
57 Protocol :: integer() >= 0,
58 OptionNum :: integer() >= 0,
59 ValueSpec ::
60 (ValueSize :: integer() >= 0) | (ValueBin :: binary())} |
61 read_packets |
62 recbuf |
63 reuseaddr |
64 sndbuf |
65 tos |
66 ipv6_v6only
67 socket()
69 As returned by open/1,2.
71
73 close(Socket) -> ok
74 Types:
76 Socket = socket()
78 Closes a UDP socket.
80 controlling_process(Socket, Pid) -> ok | {error, Reason}
82 Types:
84 Socket = socket()
86 Pid = pid()
87 Reason = closed | not_owner | badarg | inet:posix()
88 Assigns a new controlling process Pid to Socket. The controlling
90 process is the process that receives messages from the socket.
91 If called by any other process than the current controlling
92 process, {error, not_owner} is returned. If the process identi‐
93 fied by Pid is not an existing local pid, {error, badarg} is
94 returned. {error, badarg} may also be returned in some cases
95 when Socket is closed during the execution of this function.
96 open(Port) -> {ok, Socket} | {error, Reason}
98 open(Port, Opts) -> {ok, Socket} | {error, Reason}
100 Types:
102 Port = inet:port_number()
104 Opts = [Option]
105 Option =
106 {ip, inet:socket_address()} |
107 {fd, integer() >= 0} |
108 {ifaddr, inet:socket_address()} |
109 inet:address_family() |
110 {port, inet:port_number()} |
111 option()
112 Socket = socket()
113 Reason = inet:posix()
114 Associates a UDP port number (Port) with the calling process.
116 The following options are available:
118 list:
120 Received Packet is delivered as a list.
121 binary:
123 Received Packet is delivered as a binary.
124 {ip, Address}:
126 If the host has many network interfaces, this option speci‐
127 fies which one to use.
128 {ifaddr, Address}:
130 Same as {ip, Address}. If the host has many network inter‐
131 faces, this option specifies which one to use.
132 {fd, integer() >= 0}:
134 If a socket has somehow been opened without using gen_udp,
135 use this option to pass the file descriptor for it. If Port
136 is not set to 0 and/or {ip, ip_address()} is combined with
137 this option, the fd is bound to the specified interface and
138 port after it is being opened. If these options are not
139 specified, it is assumed that the fd is already bound appro‐
140 priately.
141 inet6:
143 Sets up the socket for IPv6.
144 inet:
146 Sets up the socket for IPv4.
147 local:
149 Sets up a Unix Domain Socket. See inet:local_address()
150 {udp_module, module()}:
152 Overrides which callback module is used. Defaults to
153 inet_udp for IPv4 and inet6_udp for IPv6.
154 {multicast_if, Address}:
156 Sets the local device for a multicast socket.
157 {multicast_loop, true | false}:
159 When true, sent multicast packets are looped back to the
160 local sockets.
161 {multicast_ttl, Integer}:
163 Option multicast_ttl changes the time-to-live (TTL) for out‐
164 going multicast datagrams to control the scope of the multi‐
165 casts.
166 Datagrams with a TTL of 1 are not forwarded beyond the local
168 network. Defaults to 1.
169 {add_membership, {MultiAddress, InterfaceAddress}}:
171 Joins a multicast group.
172 {drop_membership, {MultiAddress, InterfaceAddress}}:
174 Leaves a multicast group.
175 Opt:
177 See inet:setopts/2.
178 The returned socket Socket is used to send packets from this
180 port with send/4. When UDP packets arrive at the opened port, if
181 the socket is in an active mode, the packets are delivered as
182 messages to the controlling process:
183 {udp, Socket, IP, InPortNo, Packet}
185 If the socket is not in an active mode, data can be retrieved
187 through the recv/2,3 calls. Notice that arriving UDP packets
188 that are longer than the receive buffer option specifies can be
189 truncated without warning.
190 When a socket in {active, N} mode (see inet:setopts/2 for
192 details), transitions to passive ({active, false}) mode, the
193 controlling process is notified by a message of the following
194 form:
195 {udp_passive, Socket}
197 IP and InPortNo define the address from which Packet comes.
199 Packet is a list of bytes if option list is specified. Packet is
200 a binary if option binary is specified.
201 Default value for the receive buffer option is {recbuf, 8192}.
203 If Port == 0, the underlying OS assigns a free UDP port, use
205 inet:port/1 to retrieve it.
206 recv(Socket, Length) ->
208 {ok, {Address, Port, Packet}} | {error, Reason}
209 recv(Socket, Length, Timeout) ->
211 {ok, {Address, Port, Packet}} | {error, Reason}
212 Types:
214 Socket = socket()
216 Length = integer() >= 0
217 Timeout = timeout()
218 Address = inet:ip_address() | inet:returned_non_ip_address()
219 Port = inet:port_number()
220 Packet = string() | binary()
221 Reason = not_owner | inet:posix()
222 Receives a packet from a socket in passive mode. Optional param‐
224 eter Timeout specifies a time-out in milliseconds. Defaults to
225 infinity.
226 send(Socket, Address, Port, Packet) -> ok | {error, Reason}
228 Types:
230 Socket = socket()
232 Address = inet:socket_address() | inet:hostname()
233 Port = inet:port_number()
234 Packet = iodata()
235 Reason = not_owner | inet:posix()
236 Sends a packet to the specified address and port. Argument
238 Address can be a hostname or a socket address.
239Ericsson AB kernel 5.4.3.2 gen_udp(3)