Provided by: erlang-manpages_25.3.2.8+dfsg-1ubuntu4_all 
NAME
socket - Socket interface.
DESCRIPTION
This module provides an API for network socket. Functions are provided to create, delete
and manipulate the sockets as well as sending and receiving data on them.
The intent is that it shall be as "close as possible" to the OS level socket interface.
The only significant addition is that some of the functions, e.g. recv/3, have a time-out
argument.
Note:
Some functions allow for an asynchronous call. This is achieved by setting the Timeout
argument to nowait. For instance, if calling the recv/3 function with Timeout set to
nowait (recv(Sock, 0, nowait)) when there is actually nothing to read, it will return with
{select, SelectInfo} (SelectInfo contains the SelectHandle). When data eventually arrives
a 'select' message will be sent to the caller:
: {'$socket', socket(), select, SelectHandle}
The caller can now call the recv function again and probably expect data (it is really up
to the OS network protocol implementation).
Note that all other users are locked out until the 'current user' has called the function
(recv in this case) and its return value shows that the operation has completed. An
operation can also be cancelled with cancel/2.
Instead of Timeout = nowait it is equivalent to create a SelectHandle) with make_ref() and
give as Timeout. This will then be the SelectHandle in the 'select' message, which enables
a compiler optimization for receiving a message containing a newly created reference()
(ignore the part of the message queue that had arrived before the the reference() was
created).
Another message the user must be prepared for (when making asynchronous calls) is the
abort message:
: {'$socket', socket(), abort, Info}
This message indicates that the (asynchronous) operation has been aborted. If, for
instance, the socket has been closed (by another process), Info will be {SelectHandle,
closed}.
Note:
There is currently no support for Windows.
Support for IPv6 has been implemented but not tested.
SCTP has only been partly implemented (and not tested).
DATA TYPES
invalid() = {invalid, What :: term()}
domain() = inet | inet6 | local | unspec
A lowercase atom() representing a protocol domain on the platform named AF_* (or
PF_*).
The calls supports(), is_supported(ipv6) and is_supported(local) tells if the IPv6
protocol for the inet6 protocol domain / address family, and if the local protocol
domain / address family is supported by the platform's header files.
type() = stream | dgram | raw | rdm | seqpacket
A lowercase atom() representing a protocol type on the platform named SOCK_*.
protocol() = atom()
An atom() means any protocol as enumerated by the C library call getprotoent() on
the platform, or at least the supported ones of ip | ipv6 | tcp | udp | sctp.
See open/2,3,4
The call supports(protocols) returns which protocols are supported, and
is_supported(protocols, Protocol) tells if Protocol is among the enumerated.
socket() = {'$socket', socket_handle()}
As returned by open/1,2,3,4 and accept/1,2.
socket_handle()
An opaque socket handle unique for the socket.
select_tag()
A tag that describes the (select) operation, contained in the returned
select_info().
select_handle() = reference()
A reference() that uniquely identifies the (select) operation, contained in the
returned select_info().
select_info() =
{select_info,
SelectTag :: select_tag(),
SelectHandle :: select_handle()}
Returned by an operation that requires the caller to wait for a select message
containing the SelectHandle.
info() =
#{counters := #{atom() := integer() >= 0},
iov_max := integer() >= 0,
use_registry := boolean()}
The smallest allowed iov_max value according to POSIX is 16, but check your
platform documentation to be sure.
socket_counters() =
#{read_byte := integer() >= 0,
read_fails := integer() >= 0,
read_pkg := integer() >= 0,
read_pkg_max := integer() >= 0,
read_tries := integer() >= 0,
read_waits := integer() >= 0,
write_byte := integer() >= 0,
write_fails := integer() >= 0,
write_pkg := integer() >= 0,
write_pkg_max := integer() >= 0,
write_tries := integer() >= 0,
write_waits := integer() >= 0,
sendfile => integer() >= 0,
sendfile_byte => integer() >= 0,
sendfile_fails => integer() >= 0,
sendfile_max => integer() >= 0,
sendfile_pkg => integer() >= 0,
sendfile_pkg_max => integer() >= 0,
sendfile_tries => integer() >= 0,
sendfile_waits => integer() >= 0,
acc_success := integer() >= 0,
acc_fails := integer() >= 0,
acc_tries := integer() >= 0,
acc_waits := integer() >= 0}
info_keys() =
[domain | type | protocol | fd | owner | local_address |
remote_address | recv | sent | state]
Defines the information elements of the table(s) printed by the i/0, i/1 and i/2
functions.
socket_info() =
#{domain := domain() | integer(),
type := type() | integer(),
protocol := protocol() | integer(),
owner := pid(),
ctype := normal | fromfd | {fromfd, integer()},
counters := socket_counters(),
num_readers := integer() >= 0,
num_writers := integer() >= 0,
num_acceptors := integer() >= 0,
writable := boolean(),
readable := boolean(),
rstates := [atom()],
wstates := [atom()]}
in_addr() = {0..255, 0..255, 0..255, 0..255}
in6_addr() =
{0..65535,
0..65535,
0..65535,
0..65535,
0..65535,
0..65535,
0..65535,
0..65535}
sockaddr() =
sockaddr_in() |
sockaddr_in6() |
sockaddr_un() |
sockaddr_ll() |
sockaddr_dl() |
sockaddr_unspec() |
sockaddr_native()
sockaddr_recv() = sockaddr() | binary()
sockaddr_in() =
#{family := inet,
port := port_number(),
addr := any | broadcast | loopback | in_addr()}
sockaddr_in6() =
#{family := inet6,
port := port_number(),
addr := any | loopback | in6_addr(),
flowinfo := in6_flow_info(),
scope_id := in6_scope_id()}
sockaddr_un() = #{family := local, path := binary() | string()}
The path element will always be a binary when returned from this module. When
supplied to an API function in this module it may be a string(), which will be
encoded into a binary according to the native file name encoding on the platform.
A terminating zero character will be appended before the address path is given to
the OS, and the terminating zero will be stripped before giving the address path to
the caller.
Linux's non-portable abstract socket address extension is handled by not doing any
terminating zero processing in either direction, if the first byte of the address
is zero.
sockaddr_ll() =
#{family := packet,
protocol := integer() >= 0,
ifindex := integer(),
pkttype := packet_type(),
hatype := hatype(),
addr := binary()}
sockaddr_dl() =
#{family := link,
index := integer() >= 0,
type := integer() >= 0,
nlen := integer() >= 0,
alen := integer() >= 0,
slen := integer() >= 0,
data := binary()}
sockaddr_unspec() = #{family := unspec, addr := binary()}
sockaddr_native() = #{family := integer(), addr := binary()}
packet_type() =
host | broadcast | multicast | otherhost | outgoing |
loopback | user | kernel | fastroute |
integer() >= 0
hatype() =
netrom | eether | ether | ax25 | pronet | chaos | ieee802 |
arcnet | appletlk | dlci | atm | metricom | ieee1394 | eui64 |
infiniband | tunnel | tunnel6 | loopback | localtlk | none |
void |
integer() >= 0
port_number() = 0..65535
in6_flow_info() = 0..1048575
in6_scope_id() = 0..4294967295
msg_flag() =
cmsg_cloexec | confirm | ctrunc | dontroute | eor | errqueue |
more | oob | peek | trunc
Flags corresponding to the message flag constants on the platform. The flags are
lowercase and the constants are uppercase with the prefix MSG_.
Some flags are only used for sending, some only for receiving, some in received
control messages, and some for several of these. Not all flags are supported on all
platforms. See the platform's documentation, supports(msg_flags), and
is_supported(msg_flags, MsgFlag).
level() = socket | protocol()
The OS protocol levels for, for example, socket options and control messages, with
the following names in the OS header files:
socket:
SOL_SOCKET with options named SO_*.
ip:
IPPROTO_IP a.k.a SOL_IP with options named IP_*.
ipv6:
IPPROTO_IPV6 a.k.a SOL_IPV6 with options named IPV6_*.
tcp:
IPPROTO_TCP with options named TCP_*.
udp:
IPPROTO_UDP with options named UDP_*.
sctp:
IPPROTO_SCTP with options named SCTP_*.
There are many other possible protocols, but the ones above are those for which
this socket library implements socket options and/or control messages.
All protocols known to the OS are enumerated when the Erlang VM is started. See the
OS man page for protocols(5). The protocol level 'socket' is always implemented as
SOL_SOCKET and all the others mentioned in the list above are valid, if supported
by the platform, enumerated or not.
The calls supports() and is_supported(protocols, Protocol) can be used to find out
if protocols ipv6 and/or sctp are supported according to the platform's header
files.
otp_socket_option() =
debug | iow | controlling_process | rcvbuf | rcvctrlbuf |
sndctrlbuf | meta | use_registry | fd | domain
These are socket options for the otp protocol level, that is {otp, Name} options,
above all OS protocol levels. They affect Erlang/OTP's socket implementation.
debug:
boolean() - Activate debug printout.
iow:
boolean() - Inform On Wrap of statistics counters.
controlling_process:
pid() - The socket "owner". Only the current controlling process can set this
option.
rcvbuf:
BufSize :: (default | integer()>0) | {N :: integer()>0, BufSize :: (default |
integer()>0)} - Receive buffer size. The value default is only valid to set. N
specifies the number of read attempts to do in a tight loop before assuming no
more data is pending.
rcvctrlbuf:
BufSize :: (default | integer()>0) - Buffer size for received ancillary
messages. The value default is only valid to set.
sndctrlbuf:
BufSize :: (default | integer()>0) - Buffer size for sent ancillary messages.
The value default is only valid to set.
fd:
integer() - Only valid to get. The OS protocol levels' socket descriptor.
Functions open/1,2 can be used to create a socket according to this module from
an existing OS socket descriptor.
use_registry:
boolean() - Only valid to get. The value is set when the socket is created with
open/2 or open/4.
Options not described here are intentionally undocumented and for Erlang/OTP
internal use only.
socket_option() =
{Level :: socket,
Opt ::
acceptconn | acceptfilter | bindtodevice | broadcast |
busy_poll | debug | domain | dontroute | error |
keepalive | linger | mark | oobinline | passcred |
peek_off | peercred | priority | protocol | rcvbuf |
rcvbufforce | rcvlowat | rcvtimeo | reuseaddr |
reuseport | rxq_ovfl | setfib | sndbuf | sndbufforce |
sndlowat | sndtimeo | timestamp | type} |
{Level :: ip,
Opt ::
add_membership | add_source_membership | block_source |
dontfrag | drop_membership | drop_source_membership |
freebind | hdrincl | minttl | msfilter | mtu |
mtu_discover | multicast_all | multicast_if |
multicast_loop | multicast_ttl | nodefrag | options |
pktinfo | recvdstaddr | recverr | recvif | recvopts |
recvorigdstaddr | recvtos | recvttl | retopts |
router_alert | sndsrcaddr | tos | transparent | ttl |
unblock_source} |
{Level :: ipv6,
Opt ::
addrform | add_membership | authhdr | auth_level |
checksum | drop_membership | dstopts | esp_trans_level |
esp_network_level | faith | flowinfo | hopopts |
ipcomp_level | join_group | leave_group | mtu |
mtu_discover | multicast_hops | multicast_if |
multicast_loop | portrange | pktoptions | recverr |
recvhoplimit | hoplimit | recvpktinfo | pktinfo |
recvtclass | router_alert | rthdr | tclass |
unicast_hops | use_min_mtu | v6only} |
{Level :: tcp,
Opt ::
congestion | cork | info | keepcnt | keepidle |
keepintvl | maxseg | md5sig | nodelay | noopt | nopush |
syncnt | user_timeout} |
{Level :: udp, Opt :: cork} |
{Level :: sctp,
Opt ::
adaption_layer | associnfo | auth_active_key |
auth_asconf | auth_chunk | auth_key | auth_delete_key |
autoclose | context | default_send_params |
delayed_ack_time | disable_fragments | hmac_ident |
events | explicit_eor | fragment_interleave |
get_peer_addr_info | initmsg | i_want_mapped_v4_addr |
local_auth_chunks | maxseg | maxburst | nodelay |
partial_delivery_point | peer_addr_params |
peer_auth_chunks | primary_addr | reset_streams |
rtoinfo | set_peer_primary_addr | status |
use_ext_recvinfo}
Socket option on the form {Level, Opt} where the OS protocol Level = level() and
Opt is a socket option on that protocol level.
The OS name for an options is, except where otherwise noted, the Opt atom, in
capitals, with prefix according to level().
Note:
The IPv6 option pktoptions is a special (barf) case. It is intended for backward
compatibility usage only.
Do not use this option.
Note:
See the OS documentation for every socket option.
An option below that has the value type boolean() will translate the value false to
a C int with value 0, and the value true to !!0 (not (not false)).
An option with value type integer() will be translated to a C int that may have a
restricted range, for example byte: 0..255. See the OS documentation.
The calls supports(options), supports(options, Level) and is_supported(options,
{Level, Opt}) can be used to find out which socket options that are supported by
the platform.
Options for protocol level socket:
{socket, acceptconn}:
Value = boolean()
{socket, bindtodevice}:
Value = string()
{socket, broadcast}:
Value = boolean()
{socket, debug}:
Value = integer()
{socket, domain}:
Value = domain()
Only valid to get.
The socket's protocol domain. Does not work on for instance FreeBSD.
{socket, dontroute}:
Value = boolean()
{socket, keepalive}:
Value = boolean()
{socket, linger}:
Value = abort | linger()
The value abort is shorthand for #{onoff => true, linger => 0}, and only valid
to set.
{socket, oobinline}:
Value = boolean()
{socket, passcred}:
Value = boolean()
{socket, peek_off}:
Value = integer()
Currently disabled due to a possible infinite loop when calling recv/1-4 with
peek in Flags.
{socket, priority}:
Value = integer()
{socket, protocol}:
Value = protocol()
Only valid to get.
The socket's protocol. Does not work on for instance Darwin.
{socket, rcvbuf}:
Value = integer()
{socket, rcvlowat}:
Value = integer()
{socket, rcvtimeo}:
Value = timeval()
This option is unsupported per default; OTP has to be explicitly built with the
--enable-esock-rcvsndtimeo configure option for this to be available.
Since our implementation uses nonblocking sockets, it is unknown if and how
this option works, or even if it may cause malfunction. Therefore, we do not
recommend setting this option.
Instead, use the Timeout argument to, for instance, the recv/3 function.
{socket, reuseaddr}:
Value = boolean()
{socket, reuseport}:
Value = boolean()
{socket, sndbuf}:
Value = integer()
{socket, sndlowat}:
Value = integer()
{socket, sndtimeo}:
Value = timeval()
This option is unsupported per default; OTP has to be explicitly built with the
--enable-esock-rcvsndtimeo configure option for this to be available.
Since our implementation uses nonblocking sockets, it is unknown if and how
this option works, or even if it may cause malfunction. Therefore, we do not
recommend setting this option.
Instead, use the Timeout argument to, for instance, the send/3 function.
{socket, timestamp}:
Value = boolean()
{socket, type}:
Value = type()
Only valid to get.
The socket's type.
Options for protocol level ip:
{ip, add_membership}:
Value = ip_mreq()
Only valid to set.
{ip, add_source_membership}:
Value = ip_mreq_source()
Only valid to set.
{ip, block_source}:
Value = ip_mreq_source()
Only valid to set.
{ip, drop_membership}:
Value = ip_mreq()
Only valid to set.
{ip, drop_source_membership}:
Value = ip_mreq_source()
Only valid to set.
{ip, freebind}:
Value = boolean()
{ip, hdrincl}:
Value = boolean()
{ip, minttl}:
Value = integer()
{ip, msfilter}:
Value = null | ip_msfilter()
Only valid to set.
The value null passes a NULL pointer and size 0 to the C library call.
{ip, mtu}:
Value = integer()
Only valid to get.
{ip, mtu_discover}:
Value = ip_pmtudisc() | integer()
An integer() value is according to the platform's header files.
{ip, multicast_all}:
Value = boolean()
{ip, multicast_if}:
Value = any | in_addr()
{ip, multicast_loop}:
Value = boolean()
{ip, multicast_ttl}:
Value = integer()
{ip, nodefrag}:
Value = boolean()
{ip, pktinfo}:
Value = boolean()
{ip, recvdstaddr}:
Value = boolean()
{ip, recverr}:
Value = boolean()
Warning! When this option is enabled, error messages may arrive on the socket's
error queue, which should be read using the message flag errqueue, and using
recvmsg/1,2,3,4,5 to get all error information in the message's ctrl field as a
control message #{level := ip, type := recverr}.
A working strategy should be to first poll the error queue using recvmsg/2,3,4
with Timeout =:= 0 and Flags containing errqueue (ignore the return value
{error, timeout}) before reading the actual data to ensure that the error queue
gets cleared. And read the data using one of the nowait | select_handle() recv
functions: recv/3,4, recvfrom/3,4 or recvmsg/3,4,5. Otherwise you might
accidentally cause a busy loop in and out of 'select' for the socket.
{ip, recvif}:
Value = boolean()
{ip, recvopts}:
Value = boolean()
{ip, recvorigdstaddr}:
Value = boolean()
{ip, recvtos}:
Value = boolean()
{ip, recvttl}:
Value = boolean()
{ip, retopts}:
Value = boolean()
{ip, router_alert}:
Value = integer()
{ip, sendsrcaddr}:
Value = boolean()
{ip, tos}:
Value = ip_tos() | integer()
An integer() value is according to the platform's header files.
{ip, transparent}:
Value = boolean()
{ip, ttl}:
Value = integer()
{ip, unblock_source}:
Value = ip_mreq_source()
Only valid to set.
Options for protocol level ipv6:
{ipv6, addrform}:
Value = domain()
As far as we know the only valid value is inet and it is only allowed for an
IPv6 socket that is connected and bound to an IPv4-mapped IPv6 address.
{ipv6, add_membership}:
Value = ipv6_mreq()
Only valid to set.
{ipv6, authhdr}:
Value = boolean()
{ipv6, drop_membership}:
Value = ipv6_mreq()
Only valid to set.
{ipv6, dstopts}:
Value = boolean()
{ipv6, flowinfo}:
Value = boolean()
{ipv6, hoplimit}:
Value = boolean()
{ipv6, hopopts}:
Value = boolean()
{ipv6, mtu}:
Value = integer()
{ipv6, mtu_discover}:
Value = ipv6_pmtudisc() | integer()
An integer() value is according to the platform's header files.
{ipv6, multicast_hops}:
Value = ipv6_hops()
{ipv6, multicast_if}:
Value = integer()
{ipv6, multicast_loop}:
Value = boolean()
{ipv6, recverr}:
Value = boolean()
Warning! See the socket option {ip, recverr} regarding the socket's error
queue. The same warning applies for this option.
{ipv6, recvhoplimit}:
Value = boolean()
{ipv6, recvpktinfo}:
Value = boolean()
{ipv6, recvtclass}:
Value = boolean()
{ipv6, router_alert}:
Value = integer()
{ipv6, rthdr}:
Value = boolean()
{ipv6, tclass}:
Value = boolean()
{ipv6, unicast_hops}:
Value = ipv6_hops()
{ipv6, v6only}:
Value = boolean()
Options for protocol level sctp. See also RFC 6458.
{sctp, associnfo}:
Value = sctp_assocparams()
{sctp, autoclose}:
Value = integer()
{sctp, disable_fragments}:
Value = boolean()
{sctp, events}:
Value = sctp_event_subscribe()
Only valid to set.
{sctp, initmsg}:
Value = sctp_initmsg()
{sctp, maxseg}:
Value = integer()
{sctp, nodelay}:
Value = boolean()
{sctp, rtoinfo}:
Value = sctp_rtoinfo()
Options for protocol level tcp:
{tcp, congestion}:
Value = string()
{tcp, cork}:
Value = boolean()
{tcp, maxseg}:
Value = integer()
{tcp, nodelay}:
Value = boolean()
Options for protocol level udp:
{udp, cork}:
Value = boolean()
linger() = #{onoff := boolean(), linger := integer() >= 0}
Corresponds to the C struct linger for managing the socket option {socket, linger}.
timeval() = #{sec := integer(), usec := integer()}
Corresponds to the C struct timeval. The field sec holds seconds, and usec
microseconds.
ip_mreq() = #{multiaddr := in_addr(), interface := in_addr()}
Corresponds to the C struct ip_mreq for managing multicast groups.
ip_mreq_source() =
#{multiaddr := in_addr(),
interface := in_addr(),
sourceaddr := in_addr()}
Corresponds to the C struct ip_mreq_source for managing multicast groups.
ip_msfilter() =
#{multiaddr := in_addr(),
interface := in_addr(),
mode := include | exclude,
slist := [in_addr()]}
Corresponds to the C struct ip_msfilter for managing multicast source filtering
(RFC 3376).
ip_pmtudisc() = want | dont | do | probe
Lowercase atom() values corresponding to the C library constants IP_PMTUDISC_*.
Some constant(s) may be unsupported by the platform.
ip_tos() = lowdelay | throughput | reliability | mincost
Lowercase atom() values corresponding to the C library constants IPTOS_*. Some
constant(s) may be unsupported by the platform.
ip_pktinfo() =
#{ifindex := integer() >= 0,
spec_dst := in_addr(),
addr := in_addr()}
ipv6_mreq() =
#{multiaddr := in6_addr(), interface := integer() >= 0}
Corresponds to the C struct ipv6_mreq for managing multicast groups. See also RFC
2553.
ipv6_hops() = default | 0..255
The value default is only valid to set and is translated to the C value -1, meaning
the route default.
ipv6_pmtudisc() = want | dont | do | probe
Lowercase atom() values corresponding to the C library constants IPV6_PMTUDISC_*.
Some constant(s) may be unsupported by the platform.
ipv6_pktinfo() = #{addr := in6_addr(), ifindex := integer()}
sctp_assocparams() =
#{assoc_id := integer(),
asocmaxrxt := 0..65535,
numbe_peer_destinations := 0..65535,
peer_rwnd := 0..4294967295,
local_rwnd := 0..4294967295,
cookie_life := 0..4294967295}
Corresponds to the C struct sctp_assocparams.
sctp_event_subscribe() =
#{data_io := boolean(),
association := boolean(),
address := boolean(),
send_failure := boolean(),
peer_error := boolean(),
shutdown := boolean(),
partial_delivery := boolean(),
adaptation_layer => boolean(),
sender_dry => boolean()}
Corresponds to the C struct sctp_event_subscribe.
Not all fields are implemented on all platforms; unimplemented fields are ignored,
but implemented fields are mandatory. Note that the '_event' suffixes have been
stripped from the C struct field names, for convenience.
sctp_initmsg() =
#{num_ostreams := 0..65535,
max_instreams := 0..65535,
max_attempts := 0..65535,
max_init_timeo := 0..65535}
Corresponds to the C struct sctp_initmsg.
sctp_rtoinfo() =
#{assoc_id := integer(),
initial := 0..4294967295,
max := 0..4294967295,
min := 0..4294967295}
Corresponds to the C struct sctp_rtoinfo.
msg() = msg_send() | msg_recv()
msg_send() =
#{addr => sockaddr(),
iov := erlang:iovec(),
ctrl =>
[cmsg_send() |
#{level := level() | integer(),
type := integer(),
data := binary()}]}
Message sent by sendmsg/2,3,4.
Corresponds to a C struct msghdr, see your platform documentation for sendmsg(2).
addr:
Optional peer address, used on unconnected sockets. Corresponds to msg_name
and msg_namelen fields of a struct msghdr. If not used they are set to NULL, 0.
iov:
Mandatory data as a list of binaries. The msg_iov and msg_iovlen fields of a
struct msghdr.
ctrl:
Optional list of control messages (CMSG). Corresponds to the msg_control and
msg_controllen fields of a struct msghdr. If not used they are set to NULL, 0.
The msg_flags field of the struct msghdr is set to 0.
msg_recv() =
#{addr => sockaddr_recv(),
iov := erlang:iovec(),
ctrl :=
[cmsg_recv() |
#{level := level() | integer(),
type := integer(),
data := binary()}],
flags := [msg_flag() | integer()]}
Message returned by recvmsg/1,2,3,5.
Corresponds to a C struct msghdr, see your platform documentation for recvmsg(2).
addr:
Optional peer address, used on unconnected sockets. Corresponds to msg_name
and msg_namelen fields of a struct msghdr. If NULL the map key is not present.
iov:
Data as a list of binaries. The msg_iov and msg_iovlen fields of a struct
msghdr.
ctrl:
A possibly empty list of control messages (CMSG). Corresponds to the
msg_control and msg_controllen fields of a struct msghdr.
flags:
Message flags. Corresponds to the msg_flags field of a struct msghdr. Unknown
flags, if any, are returned in one integer(), last in the containing list.
native_value() = integer() | boolean() | binary()
cmsg_send() =
#{level := socket,
type := timestamp,
data => native_value(),
value => timeval()} |
#{level := socket, type := rights, data := native_value()} |
#{level := socket,
type := credentials,
data := native_value()} |
#{level := ip,
type := tos,
data => native_value(),
value => ip_tos() | integer()} |
#{level := ip,
type := ttl,
data => native_value(),
value => integer()} |
#{level := ip,
type := hoplimit,
data => native_value(),
value => integer()} |
#{level := ipv6,
type := tclass,
data => native_value(),
value => integer()}
Control messages (ancillary messages) accepted by sendmsg/2,3,4.
A control message may for some message types have a value field with a symbolic
value, or a data field with a native value, that has to be binary compatible what
is defined in the platform's header files.
cmsg_recv() =
#{level := socket,
type := timestamp,
data := binary(),
value => timeval()} |
#{level := socket, type := rights, data := binary()} |
#{level := socket, type := credentials, data := binary()} |
#{level := ip,
type := tos,
data := binary(),
value => ip_tos() | integer()} |
#{level := ip,
type := recvtos,
data := binary(),
value := ip_tos() | integer()} |
#{level := ip,
type := ttl,
data := binary(),
value => integer()} |
#{level := ip,
type := recvttl,
data := binary(),
value := integer()} |
#{level := ip,
type := pktinfo,
data := binary(),
value => ip_pktinfo()} |
#{level := ip,
type := origdstaddr,
data := binary(),
value => sockaddr_recv()} |
#{level := ip,
type := recverr,
data := binary(),
value => extended_err()} |
#{level := ipv6,
type := hoplimit,
data := binary(),
value => integer()} |
#{level := ipv6,
type := pktinfo,
data := binary(),
value => ipv6_pktinfo()} |
#{level := ipv6,
type := recverr,
data := binary(),
value => extended_err()} |
#{level := ipv6,
type := tclass,
data := binary(),
value => integer()}
Control messages (ancillary messages) returned by recvmsg/1,2,3,5.
A control message has got a data field with a native (binary) value for the message
data, and may also have a decoded value field if this socket library successfully
decoded the data.
icmp_dest_unreach() =
net_unreach | host_unreach | port_unreach | frag_needed |
net_unknown | host_unknown
icmpv6_dest_unreach() =
noroute | adm_prohibited | not_neighbour | addr_unreach |
port_unreach | policy_fail | reject_route
ee_origin() = none | local | icmp | icmp6
extended_err() =
#{error := posix(),
origin := icmp,
type := dest_unreach,
code := icmp_dest_unreach() | 0..255,
info := 0..4294967295,
data := 0..4294967295,
offender := sockaddr_recv()} |
#{error := posix(),
origin := icmp,
type := time_exceeded | 0..255,
code := 0..255,
info := 0..4294967295,
data := 0..4294967295,
offender := sockaddr_recv()} |
#{error := posix(),
origin := icmp6,
type := dest_unreach,
code := icmpv6_dest_unreach() | 0..255,
info := 0..4294967295,
data := 0..4294967295,
offender := sockaddr_recv()} |
#{error := posix(),
origin := icmp6,
type := pkt_toobig | time_exceeded | 0..255,
code := 0..255,
info := 0..4294967295,
data := 0..4294967295,
offender := sockaddr_recv()} |
#{error := posix(),
origin := ee_origin() | 0..255,
type := 0..255,
code := 0..255,
info := 0..4294967295,
data := 0..4294967295,
offender := sockaddr_recv()}
posix() = inet:posix()
The POSIX error codes originates from the OS level socket interface.
EXPORTS
accept(ListenSocket) -> {ok, Socket} | {error, Reason}
accept(ListenSocket, Timeout :: infinity) ->
{ok, Socket} | {error, Reason}
Types:
ListenSocket = Socket = socket()
Reason = posix() | closed | invalid()
Accept a connection on a socket.
This call is used with connection oriented socket types (stream or seqpacket). It
returns the first pending incoming connection for a listen socket, or waits for one
to arrive, and returns the (newly) connected socket.
accept(ListenSocket, Timeout :: integer() >= 0) ->
{ok, Socket} | {error, Reason}
Types:
ListenSocket = Socket = socket()
Reason = posix() | closed | invalid() | timeout
The same as accept/1 but returns {error, timeout} if no connection has been
accepted after Timeout milliseconds.
Note:
Note that if multiple calls are made only the last call is "valid":
{select, {select_info, _Handle}} = socket:accept(LSock, nowait),
{error, timeout} = socket:accept(LSock, 500),
.
.
.
In the example above, Handle is not valid once the second (accept-) call has been
made (the first call is automatically "cancelled" and an abort messaage sent, when
the second call is made). After the (accept-) call resulting in the timeout has
been made, there is no longer an active accept call!
accept(ListenSocket, Timeout :: nowait) ->
{ok, Socket} | {select, SelectInfo} | {error, Reason}
accept(ListenSocket, SelectHandle :: select_handle()) ->
{ok, Socket} | {select, SelectInfo} | {error, Reason}
Types:
ListenSocket = Socket = socket()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
The same as accept/1 but returns promptly.
When there is no pending connection to return, the function will return {select,
SelectInfo}, and the caller will later receive a select message, {'$socket',
Socket, select, SelectHandle} ( with the SelectHandle contained in the SelectInfo )
when a client connects. A subsequent call to accept/1,2 will then return the
socket.
If the time-out argument is SelectHandle, that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If the time-out argument is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If the caller doesn't want to wait for a connection, it must immediately call
cancel/2 to cancel the operation.
Note:
Note that if multiple calls are made only the last call is "valid":
{select, {select_info, _Handle1}} = socket:accept(LSock, nowait),
{select, {select_info, _Handle2}} = socket:accept(LSock, nowait),
receive
{'$socket', LSock, select, Handle2} ->
{ok, ASock} = socket:accept(LSock, nowait),
.
.
.
end
In the example above, only Handle2 is valid once the second (accept-) call has been
made (the first call is automatically "cancelled" and an abort messaage sent, when
the second call is made).
bind(Socket, Addr) -> ok | {error, Reason}
Types:
Socket = socket()
Addr = sockaddr() | any | broadcast | loopback
Reason = posix() | closed | invalid()
Bind a name to a socket.
When a socket is created (with open), it has no address assigned to it. bind
assigns the address specified by the Addr argument.
The rules used for name binding vary between domains.
If you bind a socket to an address in for example the 'inet' or 'inet6' address
families, with an ephemeral port number (0), and want to know which port that was
chosen, you can find out using something like: {ok, #{port := Port}} =
socket:sockname(Socket)
cancel(Socket, SelectInfo) -> ok | {error, Reason}
Types:
Socket = socket()
SelectInfo = select_info()
Reason = closed | invalid()
Cancel an asynchronous request.
Call this function in order to cancel a previous asynchronous call to, e.g. recv/3.
An ongoing asynchronous operation blocks the socket until the operation has been
finished in good order, or until it has been cancelled by this function.
Any other process that tries an operation of the same basic type (accept / send /
recv) will be enqueued and notified with the regular select mechanism for
asynchronous operations when the current operation and all enqueued before it has
been completed.
If SelectInfo does not match an operation in progress for the calling process, this
function returns {error, {invalid, SelectInfo}}.
close(Socket) -> ok | {error, Reason}
Types:
Socket = socket()
Reason = posix() | closed | timeout
Closes the socket.
Note:
Note that for e.g. protocol = tcp, most implementations doing a close does not
guarantee that any data sent is delivered to the recipient before the close is
detected at the remote side.
One way to handle this is to use the shutdown function (socket:shutdown(Socket,
write)) to signal that no more data is to be sent and then wait for the read side
of the socket to be closed.
connect(Socket, SockAddr) -> ok | {error, Reason}
connect(Socket, SockAddr, Timeout :: infinity) ->
ok | {error, Reason}
Types:
Socket = socket()
SockAddr = sockaddr()
Reason = posix() | closed | invalid() | already
This function connects the socket to the address specified by the SockAddr
argument, and returns when the connection has been established or failed.
If a connection attempt is already in progress (by another process), {error,
already} is returned.
connect(Socket, SockAddr, Timeout :: integer() >= 0) ->
ok | {error, Reason}
Types:
Socket = socket()
SockAddr = sockaddr()
Reason = posix() | closed | invalid() | already | timeout
The same as connect/2 but returns {error, timeout} if no connection has been
established after Timeout milliseconds.
Note:
Note that when this call has returned {error, timeout} the connection state of the
socket is uncertain since the platform's network stack may complete the connection
at any time, up to some platform specific time-out.
Repeating a connection attempt towards the same address would be ok, but towards a
different address could end up with a connection to either address.
The safe play would be to close the socket and start over.
Also note that all this applies to cancelling a connect call with a no-wait time-
out described below.
connect(Socket, SockAddr, Timeout :: nowait) ->
ok | {select, SelectInfo} | {error, Reason}
connect(Socket, SockAddr, SelectHandle :: select_handle()) ->
ok | {select, SelectInfo} | {error, Reason}
Types:
Socket = socket()
SockAddr = sockaddr()
SelectInfo = select_info()
Reason = posix() | closed | invalid() | already
The same as connect/2 but returns promptly.
If it is not possible to immediately establish a connection, the function will
return {select, SelectInfo}, and the caller will later receive a select message,
{'$socket', Socket, select, SelectHandle} ( with the SelectHandle contained in the
SelectInfo ) when the connection has been completed or failed. A subsequent call to
connect/1 will then finalize the connection and return the result.
If the time-out argument is SelectHandle, that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If the time-out argument is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If the caller doesn't want to wait for the connection to complete, it must
immediately call cancel/2 to cancel the operation.
connect(Socket) -> ok | {error, Reason}
Types:
Socket = socket()
Reason = posix() | closed | invalid()
This function finalizes a connection setup on a socket, after calling connect(_, _,
nowait | select_handle()) that returned {select, SelectInfo}, and receiving the
select message {'$socket', Socket, select, SelectHandle}, and returns whether the
connection setup was successful or not.
Instead of calling this function, for backwards compatibility, it is allowed to
call connect/2,3, but that incurs more overhead since the connect address and time-
out are processed in vain.
cancel_monitor(MRef) -> boolean()
Types:
MRef = reference()
If MRef is a reference that the calling process obtained by calling monitor/1, this
monitor is turned off. If the monitoring is already turned off, nothing happens.
The returned value is one of the following:
true:
The monitor was found and removed. In this case, no 'DOWN' message
corresponding to this monitor has been delivered and will not be delivered.
false:
The monitor was not found and could not be removed. This probably because a
'DOWN' message corresponding to this monitor has already been placed in the
caller message queue.
Failure: It is an error if MRef refers to a monitor started by another process.
getopt(X1 :: socket(),
SocketOption :: {Level :: otp, Opt :: otp_socket_option()}) ->
{ok, Value :: term()} | {error, invalid() | closed}
Gets a socket option from the protocol level otp, which is this implementation's
level above the OS protocol layers.
See the type otp_socket_option() for a description of the options on this level.
getopt(X1 :: socket(), SocketOption :: socket_option()) ->
{ok, Value :: term()} |
{error, posix() | invalid() | closed}
Gets a socket option from one of the OS's protocol levels. See the type
socket_option() for which options that this implementation knows about, how they
are related to option names in the OS, and if there are known peculiarities with
any of them.
What options are valid depends on what kind of socket it is (domain(), type() and
protocol()).
See the socket options chapter of the users guide for more info.
Note:
Not all options are valid, nor possible to get, on all platforms. That is, even if
"we" support an option; it does not mean that the underlying OS does.
getopt(Socket, Level, Opt) -> ok | {error, Reason}
Types:
Socket = socket()
Reason = inet:posix() | invalid() | closed
Backwards compatibility function.
The same as getopt(Socket, {Level, Opt})
getopt_native(X1 :: socket(),
SocketOption ::
socket_option() |
{Level :: level() | (NativeLevel :: integer()),
NativeOpt :: integer()},
ValueType :: integer) ->
{ok, Value :: integer()} |
{error, posix() | invalid() | closed}
getopt_native(X1 :: socket(),
SocketOption ::
socket_option() |
{Level :: level() | (NativeLevel :: integer()),
NativeOpt :: integer()},
ValueType :: boolean) ->
{ok, Value :: boolean()} |
{error, posix() | invalid() | closed}
getopt_native(X1 :: socket(),
SocketOption ::
socket_option() |
{Level :: level() | (NativeLevel :: integer()),
NativeOpt :: integer()},
ValueSize :: integer() >= 0) ->
{ok, Value :: binary()} |
{error, posix() | invalid() | closed}
getopt_native(X1 :: socket(),
SocketOption ::
socket_option() |
{Level :: level() | (NativeLevel :: integer()),
NativeOpt :: integer()},
ValueSpec :: binary()) ->
{ok, Value :: binary()} |
{error, posix() | invalid() | closed}
Gets a socket option that may be unknown to our implementation, or that has a type
not compatible with our implementation, that is; in "native mode".
The socket option may be specified with an ordinary socket_option() tuple, with a
known Level = level() and an integer NativeOpt, or with both an integer NativeLevel
and NativeOpt.
How to decode the option value has to be specified either with ValueType, by
specifying the ValueSize for a binary() that will contain the fetched option value,
or by specifying a binary() ValueSpec that will be copied to a buffer for the
getsockopt() call to write the value in which will be returned as a new binary().
If ValueType is integer a C type (int) will be fetched, if it is boolean a C type
(int) will be fetched and converted into a boolean() according to the C
implementation.
What options are valid depends on what kind of socket it is (domain(), type() and
protocol()).
The integer values for NativeLevel and NativeOpt as well as the Value encoding has
to be deduced from the header files for the running system.
i() -> ok
Print all sockets in table format in the erlang shell.
i(InfoKeys) -> ok
Types:
InfoKeys = info_keys()
Print all sockets in table format in the erlang shell. What information is included
is defined by InfoKeys.
i(Domain) -> ok
Types:
Domain = inet | inet6 | local
Print a selection, based on domain, of the sockets in table format in the erlang
shell.
i(Proto) -> ok
Types:
Proto = sctp | tcp | udp
Print a selection, based on protocol, of the sockets in table format in the erlang
shell.
i(Type) -> ok
Types:
Type = dgram | seqpacket | stream
Print a selection, based on type, of the sockets in table format in the erlang
shell.
i(Domain, InfoKeys) -> ok
Types:
Domain = inet | inet6 | local
InfoKeys = info_keys()
Print a selection, based on domain, of the sockets in table format in the erlang
shell. What information is included is defined by InfoKeys.
i(Proto, InfoKeys) -> ok
Types:
Proto = sctp | tcp | udp
InfoKeys = info_keys()
Print a selection, based on domain, of the sockets in table format in the erlang
shell. What information is included is defined by InfoKeys.
i(Type, InfoKeys) -> ok
Types:
Type = dgram | seqpacket | stream
InfoKeys = info_keys()
Print a selection, based on type, of the sockets in table format in the erlang
shell. What information is included is defined by InfoKeys.
info() -> info()
Get miscellaneous info about the socket library.
The function returns a map with each info item as a key-value binding.
Note:
In order to ensure data integrity, mutex'es are taken when needed. So, do not call
this function often.
info(Socket) -> socket_info()
Types:
Socket = socket()
Get miscellaneous info about the socket.
The function returns a map with each info item as a key-value binding. It reflects
the "current" state of the socket.
Note:
In order to ensure data integrity, mutex'es are taken when needed. So, do not call
this function often.
ioctl(Socket, GetRequest) -> {ok, IFConf} | {error, Reason}
Types:
Socket = socket()
GetRequest = gifconf
IFConf = [#{name := string, addr := sockaddr()}]
Reason = posix() | closed
Retrieve socket (device) parameters.
ioctl(Socket, GetRequest, NameOrIndex) ->
{ok, Result} | {error, Reason}
Types:
Socket = socket()
GetRequest =
gifname | gifindex | gifaddr | gifdstaddr | gifbrdaddr |
gifnetmask | gifhwaddr | gifmtu | giftxqlen | gifflags
NameOrIndex = string() | integer()
Result = term()
Reason = posix() | closed
Retrieve socket (device) parameters. This function retrieves a specific parameter,
according to GetRequest argument. The third argument is the (lookup) "key",
identifying the interface (usually the name of the interface).
gifname:
Get the name of the interface with the specified index (integer()).
Result, name of the interface, is a string().
gifindex:
Get the index of the interface with the specified name.
Result, interface index, is a integer().
gifaddr:
Get the address of the interface with the specified name. Result, address of
the interface, is a socket:sockaddr().
gifdstaddr:
Get the destination address of the point-to-point interface with the specified
name.
Result, destination address of the interface, is a socket:sockaddr().
gifbrdaddr:
Get the droadcast address for the interface with the specified name.
Result, broadcast address of the interface, is a socket:sockaddr().
gifnetmask:
Get the network mask for the interface with the specified name.
Result, network mask of the interface, is a socket:sockaddr().
gifhwaddr:
Get the hardware address for the interface with the specified name.
Result, hardware address of the interface, is a socket:sockaddr(). The family
field contains the 'ARPHRD' device type (or an integer).
gifmtu:
Get the MTU (Maximum Transfer Unit) for the interface with the specified name.
Result, MTU of the interface, is an integer().
giftxqlen:
Get the transmit queue length of the interface with the specified name.
Result, transmit queue length of the interface, is an integer().
gifflags:
Get the active flag word of the interface with the specified name.
Result, the active flag word of the interface, is an list of
socket:ioctl_device_flag() | integer().
ioctl(Socket, SetRequest, Name, Value) -> ok | {error, Reason}
Types:
Socket = socket()
SetRequest =
sifflags | sifaddr | sifdstaddr | sifbrdaddr | sifnetmask |
sifhwaddr | gifmtu | siftxqlen
Name = string()
Value = term()
Reason = posix() | closed
Set socket (device) parameters. This function sets a specific parameter, according
to SetRequest argument. The third argument is the "key", identifying the interface
(usually the name of the interface), and the fourth is the "new" value.
These are privileged operation's.
sifflags:
Set the the active flag word, #{Flag => boolean()}, of the interface with the
specified name.
Each flag to be changed, should be added to the value map, with the value
'true' if the flag (Flag) should be set and 'false' if the flag should be
reset.
sifaddr:
Set the address, sockaddr(), of the interface with the specified name.
sifdstaddr:
Set the destination address, sockaddr(), of a point-to-point interface with the
specified name.
sifbrdaddr:
Set the broadcast address, sockaddr(), of the interface with the specified
name.
sifnetmask:
Set the network mask, sockaddr(), of the interface with the specified name.
sifmtu:
Set the MTU (Maximum Transfer Unit), integer(), for the interface with the
specified name.
siftxqlen:
Set the transmit queue length, integer(), of the interface with the specified
name.
is_supported(Key1 :: term()) -> boolean()
is_supported(Key1 :: term(), Key2 :: term()) -> boolean()
This function retrieves information about what the platform supports, such as if
SCTP is supported, or if a socket options are supported.
For keys other than the known false is returned. Note that in a future version or
on a different platform there might be more supported items.
This functions returns a boolean corresponding to what supports/0-2 reports for the
same Key1 (and Key2).
listen(Socket) -> ok | {error, Reason}
listen(Socket, Backlog) -> ok | {error, Reason}
Types:
Socket = socket()
Backlog = integer()
Reason = posix() | closed
Listen for connections on a socket.
monitor(Socket) -> reference()
Types:
Socket = socket()
Start monitor the socket Socket.
If the monitored socket does not exist or when the monitor is triggered, a 'DOWN'
message is sent that has the following pattern:
{'DOWN', MonitorRef, socket, Object, Info}
In the monitor message MonitorRef and Type are the same as described earlier, and:
Object:
The monitored entity, socket, which triggered the event.
Info:
Either the termination reason of the socket or nosock (socket Socket did not
exist at the time of monitor creation).
Making several calls to socket:monitor/1 for the same Socket is not an error; it
results in as many independent monitoring instances.
number_of() -> integer() >= 0
Returns the number of active sockets.
open(FD) -> {ok, Socket} | {error, Reason}
open(FD, Opts) -> {ok, Socket} | {error, Reason}
Types:
FD = integer()
Opts =
#{domain => domain() | integer(),
type => type() | integer(),
protocol => default | protocol() | integer(),
dup => boolean(),
debug => boolean(),
use_registry => boolean()}
Socket = socket()
Reason = posix() | domain | type | protocol
Creates an endpoint (socket) for communication based on an already existing file
descriptor. The function attempts to retrieve domain, type and protocol from the
system. This is however not possible on all platforms, and they should then be
specified in Opts.
The Opts argument is intended for providing extra information for the open call:
domain:
Which protocol domain is the descriptor of. See also open/2,3,4.
type:
Which protocol type type is the descriptor of.
See also open/2,3,4.
protocol:
Which protocol is the descriptor of. The atom default is equivalent to the
integer protocol number 0 which means the default protocol for a given domain
and type.
If the protocol can not be retrieved from the platform for the socket, and
protocol is not specified, the default protocol is used, which may or may not
be correct.
See also open/2,3,4.
dup:
Shall the provided descriptor be duplicated (dup) or not.
Defaults to true.
debug:
Enable or disable debug during the open call.
Defaults to false.
use_registry>:
Enable or disable use of the socket registry for this socket. This overrides
the global value.
Defaults to the global value, see use_registry/1.
Note:
This function should be used with care!
On some platforms it is necessary to provide domain, type and protocol since they
cannot be retrieved from the platform.
open(Domain, Type) -> {ok, Socket} | {error, Reason}
open(Domain, Type, Opts) -> {ok, Socket} | {error, Reason}
Types:
Domain = domain() | integer()
Type = type() | integer()
Opts = map()
Socket = socket()
Reason = posix() | protocol
Creates an endpoint (socket) for communication.
The same as open(Domain, Type, default) and open(Domain, Type, default, Opts)
respectively.
open(Domain, Type, Protocol) -> {ok, Socket} | {error, Reason}
open(Domain, Type, Protocol, Opts) ->
{ok, Socket} | {error, Reason}
Types:
Domain = domain() | integer()
Type = type() | integer()
Protocol = default | protocol() | integer()
Opts =
#{netns => string(),
debug => boolean(),
use_registry => boolean()}
Socket = socket()
Reason = posix() | protocol
Creates an endpoint (socket) for communication.
Domain and Type may be integer()s, as defined in the platform's header files. The
same goes for Protocol as defined in the platform's services(5) database. See also
the OS man page for the library call socket(2).
Note:
For some combinations of Domain and Type the platform has got a default protocol
that can be selected with Protocol = default, and the platform may allow or require
selecting the default protocol, a specific protocol, or either.
Examples:
socket:open(inet, stream, tcp):
It is common that for protocol domain and type inet,stream it is allowed to
select the tcp protocol although that mostly is the default.
socket:open(local, dgram):
It is common that for the protocol domain local it is mandatory to not select a
protocol, that is; to select the default protocol.
The Opts argument is intended for "other" options. The supported option(s) are
described below:
netns: string():
Used to set the network namespace during the open call. Only supported on the
Linux platform.
debug: boolean():
Enable or disable debug during the open call.
Defaults to false.
use_registry: boolean():
Enable or disable use of the socket registry for this socket. This overrides
the global value.
Defaults to the global value, see use_registry/1.
peername(Socket) -> {ok, SockAddr} | {error, Reason}
Types:
Socket = socket()
SockAddr = sockaddr_recv()
Reason = posix() | closed
Returns the address of the peer connected to the socket.
recv(Socket) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Flags) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Length) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Flags, Timeout :: infinity) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Length, Flags) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Length, Timeout :: infinity) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Length, Flags, Timeout :: infinity) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
Types:
Socket = socket()
Length = integer() >= 0
Flags = [msg_flag() | integer()]
Data = binary()
Reason = posix() | closed | invalid()
Receives data from a socket, waiting for it to arrive.
The argument Length specifies how many bytes to receive, with the special case 0
meaning "all available".
For a socket of type stream this call will not return until all requested data can
be delivered, or if "all available" data was requested when the first data chunk
arrives.
The message Flags may be symbolic msg_flag()s and/or integer()s, as in the
platform's appropriate header files. The values of all symbolic flags and integers
are or:ed together.
When there is a socket error this function returns {error, Reason}, or if some data
arrived before the error; {error, {Reason, Data}}.
recv(Socket, Flags, Timeout :: integer() >= 0) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Length, Timeout :: integer() >= 0) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
recv(Socket, Length, Flags, Timeout :: integer() >= 0) ->
{ok, Data} | {error, Reason} | {error, {Reason, Data}}
Types:
Socket = socket()
Length = integer() >= 0
Flags = [msg_flag() | integer()]
Data = binary()
Reason = posix() | closed | invalid() | timeout
Receives data from a socket, waiting at most Timeout milliseconds for it to arrive.
The same as infinite time-out recv/1,2,3,4 but returns {error, timeout} or {error,
{timeout, Data}} after Timeout milliseconds, if the requested data has not been
delivered.
recv(Socket, Flags, SelectHandle :: nowait) ->
{ok, Data} |
{select, SelectInfo} |
{select, {SelectInfo, Data}} |
{error, Reason} |
{error, {Reason, Data}}
recv(Socket, Flags, SelectHandle :: select_handle()) ->
{ok, Data} |
{select, SelectInfo} |
{select, {SelectInfo, Data}} |
{error, Reason} |
{error, {Reason, Data}}
recv(Socket, Length, SelectHandle :: nowait) ->
{ok, Data} |
{select, SelectInfo} |
{select, {SelectInfo, Data}} |
{error, Reason} |
{error, {Reason, Data}}
recv(Socket, Length, SelectHandle :: select_handle()) ->
{ok, Data} |
{select, SelectInfo} |
{select, {SelectInfo, Data}} |
{error, Reason} |
{error, {Reason, Data}}
recv(Socket, Length, Flags, SelectHandle :: nowait) ->
{ok, Data} |
{select, SelectInfo} |
{select, {SelectInfo, Data}} |
{error, Reason} |
{error, {Reason, Data}}
recv(Socket, Length, Flags, SelectHandle :: select_handle()) ->
{ok, Data} |
{select, SelectInfo} |
{select, {SelectInfo, Data}} |
{error, Reason} |
{error, {Reason, Data}}
Types:
Socket = socket()
Length = integer() >= 0
Flags = [msg_flag() | integer()]
Data = binary()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Receives data from a socket, but returns a select continuation if the data could
not be returned immediately.
The same as infinite time-out recv/1,2,3,4 but if the data cannot be delivered
immediately, the function returns {select, SelectInfo}, and the caller will then
receive a select message, {'$socket', Socket, select, SelectHandle} ( with the
SelectHandle contained in the SelectInfo ) when data has arrived. A subsequent call
to recv/1,2,3,4 will then return the data.
If the time-out argument is SelectHandle, that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If the time-out argument is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
Note that for a socket of type stream, if Length > 0 and only part of that amount
of data is available, the function will return {ok, {Data, SelectInfo with partial
data. If the caller doesn't want to wait for more data, it must immediately call
cancel/2 to cancel the operation.
recvfrom(Socket) -> {ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, Flags) -> {ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, BufSz) -> {ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, Flags, Timeout :: infinity) ->
{ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, BufSz, Flags) ->
{ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, BufSz, Timeout :: infinity) ->
{ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, BufSz, Flags, Timeout :: infinity) ->
{ok, {Source, Data}} | {error, Reason}
Types:
Socket = socket()
BufSz = integer() >= 0
Flags = [msg_flag() | integer()]
Source = sockaddr_recv()
Data = binary()
Reason = posix() | closed | invalid()
Receive a message from a socket, waiting for it to arrive.
The function returns when a message is received, or when there is a socket error.
Argument BufSz specifies the number of bytes for the receive buffer. If the buffer
size is too small, the message will be truncated.
If BufSz is not specified or 0, a default buffer size is used, which can be set by
socket:setopt(Socket, {otp,recvbuf}, BufSz).
If it is impossible to know the appropriate buffer size, it may be possible to use
the receive message flag peek. When this flag is used, the message is not
"consumed" from the underlying buffers, so another recvfrom/1,2,3,4 call is needed,
possibly with an adjusted buffer size.
The message Flags may be symbolic msg_flag()s and/or integer()s, as in the
platform's appropriate header files. The values of all symbolic flags and integers
are or:ed together.
recvfrom(Socket, Flags, Timeout :: integer() >= 0) ->
{ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, BufSz, Timeout :: integer() >= 0) ->
{ok, {Source, Data}} | {error, Reason}
recvfrom(Socket, BufSz, Flags, Timeout :: integer() >= 0) ->
{ok, {Source, Data}} | {error, Reason}
Types:
Socket = socket()
BufSz = integer() >= 0
Flags = [msg_flag() | integer()]
Source = sockaddr_recv()
Data = binary()
Reason = posix() | closed | invalid() | timeout
Receives a message from a socket, waiting at most Timeout milliseconds for it to
arrive.
The same as infinite time-out recvfrom/1,2,3,4 but returns {error, timeout} after
Timeout milliseconds, if no message has been delivered.
recvfrom(Socket, Flags, SelectHandle :: nowait) ->
{ok, {Source, Data}} |
{select, SelectInfo} |
{error, Reason}
recvfrom(Socket, Flags, SelectHandle :: select_handle()) ->
{ok, {Source, Data}} |
{select, SelectInfo} |
{error, Reason}
recvfrom(Socket, BufSz, SelectHandle :: nowait) ->
{ok, {Source, Data}} |
{select, SelectInfo} |
{error, Reason}
recvfrom(Socket, BufSz, SelectHandle :: select_handle()) ->
{ok, {Source, Data}} |
{select, SelectInfo} |
{error, Reason}
recvfrom(Socket, BufSz, Flags, SelectHandle :: nowait) ->
{ok, {Source, Data}} |
{select, SelectInfo} |
{error, Reason}
recvfrom(Socket, BufSz, Flags, SelectHandle :: select_handle()) ->
{ok, {Source, Data}} |
{select, SelectInfo} |
{error, Reason}
Types:
Socket = socket()
BufSz = integer() >= 0
Flags = [msg_flag() | integer()]
Source = sockaddr_recv()
Data = binary()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Receives a message from a socket, but returns a select continuation if no message
could be returned immediately.
The same as infinite time-out recvfrom/1,2,3,4 but if no message cannot delivered
immediately, the function returns {select, SelectInfo}, and the caller will then
receive a select message, {'$socket', Socket, select, SelectHandle} ( with the
SelectHandle contained in the SelectInfo ) when data has arrived. A subsequent call
to recvfrom/1,2,3,4 will then return the message.
If the time-out argument is SelectHandle, that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If the time-out argument is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If the caller doesn't want to wait for the data, it must immediately call cancel/2
to cancel the operation.
recvmsg(Socket) -> {ok, Msg} | {error, Reason}
recvmsg(Socket, Flags) -> {ok, Msg} | {error, Reason}
recvmsg(Socket, Timeout :: infinity) ->
{ok, Msg} | {error, Reason}
recvmsg(Socket, Flags, Timeout :: infinity) ->
{ok, Msg} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz) -> {ok, Msg} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, Timeout :: infinity) ->
{ok, Msg} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, Flags, Timeout :: infinity) ->
{ok, Msg} | {error, Reason}
Types:
Socket = socket()
BufSz = CtrlSz = integer() >= 0
Flags = [msg_flag() | integer()]
Msg = msg_recv()
Reason = posix() | closed | invalid()
Receive a message from a socket, waiting for it to arrive.
The function returns when a message is received, or when there is a socket error.
Arguments BufSz and CtrlSz specifies the number of bytes for the receive buffer and
the control message buffer. If the buffer size(s) is(are) too small, the message
and/or control message list will be truncated.
If BufSz is not specified or 0, a default buffer size is used, which can be set by
socket:setopt(Socket, {otp,recvbuf}, BufSz). The same applies to CtrlSz and
socket:setopt(Socket, {otp,recvctrlbuf}, CtrlSz).
If it is impossible to know the appropriate buffer size, it may be possible to use
the receive message flag peek. When this flag is used, the message is not
"consumed" from the underlying buffers, so another recvfrom/1,2,3,4,5 call is
needed, possibly with an adjusted buffer size.
The message Flags may be symbolic msg_flag()s and/or integer()s, as in the
platform's appropriate header files. The values of all symbolic flags and integers
are or:ed together.
recvmsg(Socket, Timeout :: integer() >= 0) ->
{ok, Msg} | {error, Reason}
recvmsg(Socket, Flags, Timeout :: integer() >= 0) ->
{ok, Msg} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, Timeout :: integer() >= 0) ->
{ok, Msg} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, Flags,
Timeout :: integer() >= 0) ->
{ok, Msg} | {error, Reason}
Types:
Socket = socket()
BufSz = CtrlSz = integer() >= 0
Flags = [msg_flag() | integer()]
Msg = msg_recv()
Reason = posix() | closed | invalid() | timeout
Receives a message from a socket, waiting at most Timeout milliseconds for it to
arrive.
The same as recvmsg/1,2,3,4,5 but returns {error, timeout} after Timeout
milliseconds, if no message has been delivered.
recvmsg(Socket, Timeout :: nowait) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, SelectHandle :: select_handle()) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, Flags, Timeout :: nowait) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, Flags, SelectHandle :: select_handle()) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, SelectHandle :: nowait) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, SelectHandle :: select_handle()) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, Flags, SelectHandle :: nowait) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
recvmsg(Socket, BufSz, CtrlSz, Flags,
SelectHandle :: select_handle()) ->
{ok, Msg} | {select, SelectInfo} | {error, Reason}
Types:
Socket = socket()
BufSz = CtrlSz = integer() >= 0
Flags = [msg_flag() | integer()]
Msg = msg_recv()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Receives a message from a socket, but returns a select continuation if no message
could be returned immediately.
The same as infinite time-out recvfrom/1,2,3,4 but if no message cannot delivered
immediately, the function returns {select, SelectInfo}, and the caller will then
receive a select message, {'$socket', Socket, select, SelectHandle} ( with the
SelectHandle contained in the SelectInfo ) when data has arrived. A subsequent call
to recvmsg/1,2,3,4,5 will then return the data.
If the time-out argument is SelectHandle, that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If the time-out argument is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If the caller doesn't want to wait for the data, it must immediately call cancel/2
to cancel the operation.
send(Socket, Data) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
send(Socket, Data, Flags) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
send(Socket, Data, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
send(Socket, Data, Flags, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
Types:
Socket = socket()
Data = iodata()
Flags = [msg_flag() | integer()]
RestData = binary()
Reason = posix() | closed | invalid()
Sends data on a connected socket, waiting for it to be sent.
This call will not return until the Data has been accepted by the platform's
network layer, or it reports an error.
The message Flags may be symbolic msg_flag()s and/or integer()s, matching the
platform's appropriate header files. The values of all symbolic flags and integers
are or:ed together.
The Data, if it is not a binary(), is copied into one before calling the platform
network API, because a single buffer is required. A returned RestData is a sub
binary of this data binary.
The return value indicates the result from the platform's network layer:
ok:
All data has been accepted.
{ok, RestData}:
Not all data has been accepted, but no error has been reported. RestData is the
tail of Data that has not been accepted.
This cannot happen for a socket of type stream where a partially successful
send is retried until the data is either accepted or there is an error.
For a socket of type dgram this should probably also not happen since a message
that cannot be passed atomically should render an error.
It is nevertheless possible for the platform's network layer to return this.
{error, Reason}:
An error has been reported and no data has been accepted. The posix() Reasons
are from the platform's network layer. closed means that this socket library
knows that the socket is closed, and invalid() means that something about an
argument is invalid.
{error, {Reason, RestData}} :
An error has been reported but before that some data was accepted. RestData is
the tail of Data that has not been accepted. See {error, Reason} above.
This can only happen for a socket of type stream when a partially successful
send is retried until there is an error.
send(Socket, Data, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
send(Socket, Data, Flags, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
Types:
Socket = socket()
Data = iodata()
Flags = [msg_flag() | integer()]
RestData = binary()
Reason = posix() | closed | invalid()
Sends data on a connected socket, waiting at most Timeout milliseconds for it to be
sent.
The same as infinite time-out send/2,3,4 but returns {error, timeout} or {error,
{timeout, RestData}} after Timeout milliseconds, if no Data or only some of it was
accepted by the platform's network layer.
send(Socket, Data, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
send(Socket, Data, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
send(Socket, Data, Flags, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
send(Socket, Data, Flags, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
Types:
Socket = socket()
Data = iodata()
Flags = [msg_flag() | integer()]
RestData = binary()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Sends data on a connected socket, but returns a select continuation if the data
could not be sent immediately.
The same as infinite time-out send/2,3 but if the data is not immediately accepted
by the platform network layer, the function returns {select, SelectInfo}, and the
caller will then receive a select message, {'$socket', Socket, select,
SelectHandle} ( with the SelectHandle that was contained in the SelectInfo ) when
there is room for more data. A subsequent call to send/2-4 will then send the data.
If SelectHandle is a select_handle(), that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If SelectHandle is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If some of the data was sent, the function will return {ok, {RestData,
SelectInfo}, which can only happen for a socket of type stream. If the caller does
not want to wait to send the rest of the data, it should immediately cancel the
operation with cancel/2.
send(Socket, Data, Cont) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
send(Socket, Data, Cont, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
send(Socket, Data, Cont, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
send(Socket, Data, Cont, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
send(Socket, Data, Cont, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
Types:
Socket = socket()
Data = iodata()
Cont = select_info()
RestData = binary()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Continues sending data on a connected socket, where the send operation was
initiated by send/3,4 that returned a SelectInfo continuation. Otherwise like
infinite time-out send/2,3,4 , limited time-out send/3,4 or nowait send/3,4
respectively.
Cont is the SelectInfo that was returned from the previous send() call.
If Data is not a binary(), it will be copied into one, again.
The return value indicates the result from the platform's network layer. See
send/2,3,4 and nowait send/3,4.
sendmsg(Socket, Msg) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Msg, Flags) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Msg, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Msg, Flags, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
Types:
Socket = socket()
Msg = msg_send()
Flags = [msg_flag() | integer()]
RestData = erlang:iovec()
Reason = posix() | closed | invalid()
Sends a message on a socket, waiting for it to be sent.
The destination, if needed, that is: if the socket is not connected, is provided in
Msg, which also contains the data to send as a list of binaries. Msg may also
contain an list of optional control messages (depending on what the protocol and
platform supports).
For a connected socket no address field should be present in Msg, the platform may
return an error or ignore one.
The message data is given to to the platform's network layer in the form of an I/O
vector without copying the content. If the number of elements in the I/O vector is
larger than allowed on the platform (reported in the iov_max field from info/0), on
a socket of type stream the send is iterated over all elements, but for other
socket types the call fails.
This call will not return until the data has been handed over to the platform's
network layer, or when it reports an error.
The message Flags may be symbolic msg_flag()s and/or integer()s, matching the
platform's appropriate header files. The values of all symbolic flags and integers
are or:ed together.
The return value indicates the result from the platform's network layer. See
send/2,3,4.
sendmsg(Socket, Msg, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
sendmsg(Socket, Msg, Flags, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
Types:
Socket = socket()
Msg = msg_send()
Flags = [msg_flag() | integer()]
RestData = erlang:iovec()
Reason = posix() | closed | invalid()
Sends a message on a socket, waiting at most Timeout milliseconds for it to be
sent.
The same as infinite time-out sendmsg/2,3,4 but returns {error, timeout} or
{error, {timeout, RestData}} after Timeout milliseconds, if no data or only some of
it was accepted by the platform's network layer.
sendmsg(Socket, Msg, Timeout :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Msg, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Msg, Flags, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Msg, Flags, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason} |
{error, {Reason, RestData}}
Types:
Socket = socket()
Msg = msg_send()
Flags = [msg_flag() | integer()]
RestData = erlang:iovec()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Sends a message on a socket, but returns a select continuation if the data could
not be sent immediately.
The same as infinity time-out sendmsg/2,3 but if the data is not immediately
accepted by the platform network layer, the function returns {select, SelectInfo},
and the caller will then receive a select message, {'$socket', Socket, select,
SelectHandle} ( with the SelectHandle that was contained in the SelectInfo ) when
there is room for more data. A subsequent call to sendmsg/2-4 will then send the
data.
If SelectHandle, is a select_handle(), that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If SelectHandle is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If some of the data was sent, the function will return {ok, {RestData,
SelectInfo}, which can only happen for a socket of type stream. If the caller does
not want to wait to send the rest of the data, it should immediately cancel the
operation with cancel/2.
sendmsg(Socket, Data, Cont) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Data, Cont, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Data, Cont, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
sendmsg(Socket, Data, Cont, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason} |
{error, {Reason, RestData}}
sendmsg(Socket, Data, Cont, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason} |
{error, {Reason, RestData}}
Types:
Socket = socket()
Data = msg_send() | erlang:iovec()
Cont = select_info()
RestData = erlang:iovec()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Continues sending a message data on a socket, where the send operation was
initiated by sendmsg/3,4 that returned a SelectInfo continuation. Otherwise like
infinite time-out sendmsg/2,3,4 , limited time-out sendmsg/3,4 or nowait
sendmsg/3,4 respectively.
Cont is the SelectInfo that was returned from the previous sendmsg() call.
The return value indicates the result from the platform's network layer. See
send/2,3,4 and nowait sendmsg/3,4.
sendto(Socket, Data, Dest) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendto(Socket, Data, Dest, Flags) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendto(Socket, Data, Dest, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendto(Socket, Data, Dest, Flags, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
Types:
Socket = socket()
Data = iodata()
Dest = sockaddr()
Flags = [msg_flag() | integer()]
RestData = binary()
Reason = posix() | closed | invalid()
Sends data on a socket, to the specified destination, waiting for it to be sent.
This call will not return until the data has been accepted by the platform's
network layer, or it reports an error.
If this call is used on a connection mode socket or on a connected socket, the
platforms's network layer may return an error or ignore the destination address.
The message Flags may be symbolic msg_flag()s and/or integer()s, matching the
platform's appropriate header files. The values of all symbolic flags and integers
are or:ed together.
The return value indicates the result from the platform's network layer. See
send/2,3,4.
sendto(Socket, Data, Dest, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
sendto(Socket, Data, Dest, Flags, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
Types:
Socket = socket()
Data = iodata()
Dest = sockaddr()
Flags = [msg_flag() | integer()]
RestData = binary()
Reason = posix() | closed | invalid()
Sends data on a socket, waiting at most Timeout milliseconds for it to be sent.
The same as infinite time-out sendto/3,4,5 but returns {error, timeout} or {error,
{timeout, RestData}} after Timeout milliseconds, if no Data or only some of it was
accepted by the platform's network layer.
sendto(Socket, Data, Dest, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
sendto(Socket, Data, Dest, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
sendto(Socket, Data, Dest, Flags, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
sendto(Socket, Data, Dest, Flags, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
Types:
Socket = socket()
Data = iodata()
Dest = sockaddr()
Flags = [msg_flag() | integer()]
RestData = binary()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Sends data on a socket, but returns a select continuation if the data could not be
sent immediately.
The same as infinity time-out sendto/3,4 but if the data is not immediately
accepted by the platform network layer, the function returns {select, SelectInfo},
and the caller will then receive a select message, {'$socket', Socket, select,
SelectHandle} ( with the SelectHandle that was contained in the SelectInfo ) when
there is room for more data. A subsequent call to sendto/3-5 will then send the
data.
If SelectHandle is a select_handle(), that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If SelectHandle is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If some of the data was sent, the function will return {ok, {RestData,
SelectInfo}, which can only happen for a socket of type stream. If the caller does
not want to wait to send the rest of the data, it should immediately cancel the
operation with cancel/2.
sendto(Socket, Data, Cont) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendto(Socket, Data, Cont, Timeout :: infinity) ->
ok |
{ok, RestData} |
{error, Reason} |
{error, {Reason, RestData}}
sendto(Socket, Data, Cont, Timeout :: integer() >= 0) ->
ok |
{ok, RestData} |
{error, Reason | timeout} |
{error, {Reason | timeout, RestData}}
sendto(Socket, Data, Cont, SelectHandle :: nowait) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
sendto(Socket, Data, Cont, SelectHandle :: select_handle()) ->
ok |
{ok, RestData} |
{select, SelectInfo} |
{select, {SelectInfo, RestData}} |
{error, Reason}
Types:
Socket = socket()
Data = iodata()
Cont = select_info()
RestData = binary()
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Continues sending data on a socket, where the send operation was initiated by
sendto/4,5 that returned a SelectInfo continuation. Otherwise like infinite time-
out sendto/3,4,5 , limited time-out sendto/4,5 or nowait sendto/4,5 respectively.
Cont is the SelectInfo that was returned from the previous sendto() call.
If Data is not a binary(), it will be copied into one, again.
The return value indicates the result from the platform's network layer. See
send/2,3,4 and nowait sendto/4,5.
sendfile(Socket, FileHandle, Offset, Count, Timeout :: infinity) ->
{ok, BytesSent} |
{error, Reason} |
{error, {Reason, BytesSent}}
Types:
Socket = socket()
FileHandle = file:fd()
Offset = integer()
Count = BytesSent = integer() >= 0
Reason = posix() | closed | invalid()
Sends file data on a socket, to the specified destination, waiting for it to be
sent ("infinite" time-out).
The FileHandle must refer to an open raw file as described in file:open/2.
This call will not return until the data has been accepted by the platform's
network layer, or it reports an error.
The Offset argument is the file offset to start reading from. The default value is
0.
The Count argument is the number of bytes to transfer from FileHandle to Socket. If
Count =:= 0 (the default) the transfer stops at the end of file.
The return value indicates the result from the platform's network layer:
{ok, BytesSent}:
The transfer completed successfully after BytesSent bytes of data.
{error, Reason}:
An error has been reported and no data has been transferred. The posix()
Reasons are from the platform's network layer. closed means that this socket
library knows that the socket is closed, and invalid() means that something
about an argument is invalid.
{error, {Reason, BytesSent}} :
An error has been reported but before that some data was transferred. See
{error, Reason} and {ok, BytesSent} above.
sendfile(Socket, FileHandle, Offset, Count,
Timeout :: integer() >= 0) ->
{ok, BytesSent} |
{error, Reason | timeout} |
{error, {Reason | timeout, BytesSent}}
Types:
Socket = socket()
FileHandle = file:fd()
Offset = integer()
Count = BytesSent = integer() >= 0
Reason = posix() | closed | invalid()
Sends file data on a socket, waiting at most Timeout milliseconds for it to be sent
(limited time-out).
The same as "infinite" time-out sendfile/5 but returns {error, timeout} or {error,
{timeout, BytesSent}} after Timeout milliseconds, if not all file data was
transferred by the platform's network layer.
sendfile(Socket, FileHandle, Offset, Count,
SelectHandle :: nowait) ->
{ok, BytesSent} |
{select, SelectInfo} |
{select, {SelectInfo, BytesSent}} |
{error, Reason}
sendfile(Socket, FileHandle, Offset, Count,
SelectHandle :: select_handle()) ->
{ok, BytesSent} |
{select, SelectInfo} |
{select, {SelectInfo, BytesSent}} |
{error, Reason}
Types:
Socket = socket()
FileHandle = file:fd()
Offset = integer()
Count = BytesSent = integer() >= 0
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Sends file data on a socket, but returns a select continuation if the data could
not be sent immediately (nowait).
The same as "infinite" time-out sendfile/5 but if the data is not immediately
accepted by the platform network layer, the function returns {select, SelectInfo},
and the caller will then receive a select message, {'$socket', Socket, select,
SelectHandle} ( with the SelectHandle that was contained in the SelectInfo ) when
there is room for more data. Then a call to sendfile/3 with SelectInfo as the
second argument will continue the data transfer.
If SelectHandle is a select_handle(), that term will be contained in a returned
SelectInfo and the corresponding select message. The SelectHandle is presumed to be
unique to this call.
If SelectHandle is nowait, and a SelectInfo is returned, it will contain a
select_handle() generated by the call.
If some file data was sent, the function will return {ok, {BytesSent, SelectInfo}.
If the caller does not want to wait to send the rest of the data, it should
immediately cancel the operation with cancel/2.
sendfile(Socket, Cont, Offset, Count, Timeout :: infinity) ->
{ok, BytesSent} |
{error, Reason} |
{error, {Reason, BytesSent}}
sendfile(Socket, Cont, Offset, Count,
Timeout :: integer() >= 0) ->
{ok, BytesSent} |
{error, Reason | timeout} |
{error, {Reason | timeout, BytesSent}}
sendfile(Socket, Cont, Offset, Count, SelectHandle :: nowait) ->
{ok, BytesSent} |
{select, SelectInfo} |
{select, {SelectInfo, BytesSent}} |
{error, Reason}
sendfile(Socket, Cont, Offset, Count,
SelectHandle :: select_handle()) ->
{ok, BytesSent} |
{select, SelectInfo} |
{select, {SelectInfo, BytesSent}} |
{error, Reason}
Types:
Socket = socket()
Cont = select_info()
Offset = integer()
Count = BytesSent = integer() >= 0
SelectInfo = select_info()
Reason = posix() | closed | invalid()
Continues sending file data on a socket, where the send operation was initiated by
sendfile/3,5 that returned a SelectInfo continuation. Otherwise like "infinite"
time-out sendfile/5 , limited time-out sendfile/5 or nowait sendfile/5
respectively.
Cont is the SelectInfo that was returned from the previous sendfile() call.
The return value indicates the result from the platform's network layer. See
"infinite" time-out sendfile/5.
sendfile(Socket, FileHandle, Offset, Count) -> Result
Types:
Socket = socket()
FileHandle = file:fd()
Offset = integer()
Count = integer() >= 0
The same as sendfile(Socket, FileHandle, Offset, Count, infinity), that is: send
the file data at Offset and Count to the socket, without time-out other than from
the platform's network stack.
sendfile(Socket, FileHandle, Timeout) -> Result
Types:
Socket = socket()
FileHandle = file:fd()
Timeout = timeout() | 'nowait' | select_handle()
Depending on the Timeout argument; the same as sendfile(Socket, FileHandle, 0, 0,
infinity), sendfile(Socket, FileHandle, 0, 0, Timeout), or sendfile(Socket,
FileHandle, 0, 0, SelectHandle), that is: send all data in the file to the socket,
with the given Timeout.
sendfile(Socket, FileHandle) -> Result
Types:
Socket = socket()
FileHandle = file:fd()
The same as sendfile(Socket, FileHandle, 0, 0, infinity), that is: send all data
in the file to the socket, without time-out other than from the platform's network
stack.
setopt(Socket :: socket(),
SocketOption :: {Level :: otp, Opt :: otp_socket_option()},
Value :: term()) ->
ok | {error, invalid() | closed}
Sets a socket option in the protocol level otp, which is this implementation's
level above the OS protocol layers.
See the type otp_socket_option() for a description of the options on this level.
setopt(Socket :: socket(),
SocketOption :: socket_option(),
Value :: term()) ->
ok | {error, posix() | invalid() | closed}
Set a socket option in one of the OS's protocol levels. See the type
socket_option() for which options that this implementation knows about, how they
are related to option names in the OS, and if there are known peculiarities with
any of them.
What options are valid depends on what kind of socket it is (domain(), type() and
protocol()).
See the socket options chapter of the users guide for more info.
Note:
Not all options are valid, nor possible to set, on all platforms. That is, even if
"we" support an option; it does not mean that the underlying OS does.
setopt(Socket, Level, Opt, Value) -> ok | {error, Reason}
Types:
Socket = socket()
Value = term()
Reason = inet:posix() | invalid() | closed
Backwards compatibility function.
The same as setopt(Socket, {Level, Opt}, Value)
setopt_native(Socket :: socket(),
SocketOption ::
socket_option() |
{Level :: level() | (NativeLevel :: integer()),
NativeOpt :: integer()},
Value :: native_value()) ->
ok | {error, posix() | invalid() | closed}
Sets a socket option that may be unknown to our implementation, or that has a type
not compatible with our implementation, that is; in "native mode".
If Value is an integer() it will be used as a C type (int), if it is a boolean() it
will be used as a C type (int) with the C implementations values for false or true,
and if it is a binary() its content and size will be used as the option value.
The socket option may be specified with an ordinary socket_option() tuple, with a
known Level = level() and an integer NativeOpt, or with both an integer NativeLevel
and NativeOpt.
What options are valid depends on what kind of socket it is (domain(), type() and
protocol()).
The integer values for NativeLevel and NativeOpt as well as the encoding of Value
has to be deduced from the header files for the running system.
shutdown(Socket, How) -> ok | {error, Reason}
Types:
Socket = socket()
How = read | write | read_write
Reason = posix() | closed
Shut down all or part of a full-duplex connection.
sockname(Socket) -> {ok, SockAddr} | {error, Reason}
Types:
Socket = socket()
SockAddr = sockaddr_recv()
Reason = posix() | closed
Returns the current address to which the socket is bound.
supports() ->
[{Key1 :: term(),
boolean() |
[{Key2 :: term(),
boolean() | [{Key3 :: term(), boolean()}]}]}]
supports(Key1 :: term()) ->
[{Key2 :: term(),
boolean() | [{Key3 :: term(), boolean()}]}]
supports(Key1 :: term(), Key2 :: term()) ->
[{Key3 :: term(), boolean()}]
These functions function retrieves information about what the platform supports,
such which platform features or which socket options, are supported.
For keys other than the known the empty list is returned, Note that in a future
version or on a different platform there might be more supported items.
supports():
Returns a list of {Key1, supports(Key1)} tuples for every Key1 described in
supports/1 and {Key1, boolean()} tuples for each of the following keys:
sctp:
SCTP support
ipv6:
IPv6 support
local:
Unix Domain sockets support (AF_UNIX | AF_LOCAL)
netns:
Network Namespaces support (Linux, setns(2))
sendfile:
Sendfile support (sendfile(2))
supports(msg_flags = Key1):
Returns a list of {Flag, boolean()} tuples for every Flag in msg_flag() with
the boolean() indicating if the flag is supported on this platform.
supports(protocols = Key1):
Returns a list of {Name :: atom(), boolean()} tuples for every Name in
protocol() with the boolean() indicating if the protocol is supported on this
platform.
supports(options = Key1):
Returns a list of {SocketOption, boolean()} tuples for every SocketOption in
socket_option() with the boolean() indicating if the socket option is supported
on this platform.
supports(options = Key1, Key2) :
For a Key2 in level() returns a list of {Opt, boolean()} tuples for all known
socket options Opt on that Level =:= Key2, and the boolean() indicating if the
socket option is supported on this platform. See setopt/3 and getopt/2.
use_registry(D :: boolean()) -> ok
Globally change if the socket registry is to be used or not. Note that its still
possible to override this explicitly when creating an individual sockets, see
open/2 or open/4 for more info (use the Extra argument).
which_sockets() -> [socket()]
which_sockets(FilterRule) -> [socket()]
Types:
FilterRule =
inet | inet6 | local | stream | dgram | seqpacket | sctp |
tcp | udp |
pid() |
fun((socket_info()) -> boolean())
Returns a list of all sockets, according to the filter rule.
There are several pre-made filter rule(s) and one general:
inet | inet6:
Selection based on the domain of the socket.
Only a subset is valid.
stream | dgram | seqpacket:
Selection based on the type of the socket.
Only a subset is valid.
sctp | tcp | udp:
Selection based on the protocol of the socket.
Only a subset is valid.
pid():
Selection base on which sockets has this pid as Controlling Process.
fun((socket_info()) -> boolean()):
The general filter rule.
A fun that takes the socket info and returns a boolean() (true if the socket
could be included and false if should not).
EXAMPLES
client(SAddr, SPort) ->
{ok, Sock} = socket:open(inet, stream, tcp),
ok = socket:connect(Sock, #{family => inet,
addr => SAddr,
port => SPort}),
Msg = <<"hello">>,
ok = socket:send(Sock, Msg),
ok = socket:shutdown(Sock, write),
{ok, Msg} = socket:recv(Sock),
ok = socket:close(Sock).
server(Addr, Port) ->
{ok, LSock} = socket:open(inet, stream, tcp),
ok = socket:bind(LSock, #{family => inet,
port => Port,
addr => Addr}),
ok = socket:listen(LSock),
{ok, Sock} = socket:accept(LSock),
{ok, Msg} = socket:recv(Sock),
ok = socket:send(Sock, Msg),
ok = socket:close(Sock),
ok = socket:close(LSock).