1erl_epmd(3)                Erlang Module Definition                erl_epmd(3)
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NAME

6       erl_epmd -
7           Erlang interface towards epmd
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DESCRIPTION

11       This  module  communicates with the EPMD daemon, see epmd. To implement
12       your own epmd module please see ERTS User's Guide: How to Implement  an
13       Alternative Node Discovery for Erlang Distribution
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EXPORTS

16       start_link() -> {ok, pid()} | ignore | {error, term()}
17
18              This  function  is invoked as this module is added as a child of
19              the erl_distribution supervisor.
20
21       register_node(Name, Port) -> Result
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23       register_node(Name, Port, Driver) -> Result
24
25              Types:
26
27                 Name = string()
28                 Port = integer() >= 0
29                 Driver = inet_tcp | inet6_tcp | inet | inet6
30                 Creation = integer() >= 0 | -1
31                 Result =  {ok,  Creation}  |  {error,  already_registered}  |
32                 term()
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34              Registers  the  node  with epmd and tells epmd what port will be
35              used for the current node. It returns a  creation  number.  This
36              number  is  incremented on each register to help differentiate a
37              new node instance connecting to epmd with the same name.
38
39              After the node has successfully registered with epmd it will au‐
40              tomatically attempt reconnect to the daemon if the connection is
41              broken.
42
43       port_please(Name, Host) ->
44                      {port, Port, Version} |
45                      noport | closed |
46                      {error, term()}
47
48       port_please(Name, Host, Timeout) ->
49                      {port, Port, Version} |
50                      noport | closed |
51                      {error, term()}
52
53              Types:
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55                 Name = atom() | string()
56                 Host = atom() | string() | inet:ip_address()
57                 Timeout = integer() >= 0 | infinity
58                 Port = Version = integer() >= 0
59
60              Requests the distribution port for the given node of an EPMD in‐
61              stance.  Together with the port it returns a distribution proto‐
62              col version which has been 5 since Erlang/OTP R6.
63
64       listen_port_please(Name, Host) -> {ok, Port}
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66              Types:
67
68                 Name = atom() | string()
69                 Host = atom() | string() | inet:ip_address()
70                 Port = integer() >= 0
71
72              Called by the distribution module to get which  port  the  local
73              node should listen to when accepting new distribution requests.
74
75       address_please(Name, Host, AddressFamily) ->
76                         Success | {error, term()}
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78              Types:
79
80                 Name = string()
81                 Host = string() | inet:ip_address()
82                 AddressFamily = inet | inet6
83                 Port = Version = integer() >= 0
84                 Success =
85                     {ok, inet:ip_address()} |
86                     {ok, inet:ip_address(), Port, Version}
87
88              Called  by the distribution module to resolves the Host to an IP
89              address of a remote node.
90
91              As an optimization this function may also return  the  port  and
92              version  of  the  remote  node. If port and version are returned
93              port_please/3 will not be called.
94
95       names(Host) -> {ok, [{Name, Port}]} | {error, Reason}
96
97              Types:
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99                 Host = atom() | string() | inet:ip_address()
100                 Name = string()
101                 Port = integer() >= 0
102                 Reason = address | file:posix()
103
104              Called by net_adm:names/0. Host defaults to the  localhost.  Re‐
105              turns  the names and associated port numbers of the Erlang nodes
106              that epmd registered at the specified host. Returns {error,  ad‐
107              dress} if epmd is not operational.
108
109              Example:
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111              (arne@dunn)1> erl_epmd:names(localhost).
112              {ok,[{"arne",40262}]}
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116Ericsson AB                     kernel 8.5.4.2                     erl_epmd(3)
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