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
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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.
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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()}
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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.
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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.
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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.
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95       names(Host) -> {ok, [{Name, Port}]} | {error, Reason}
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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 8.1.3                      erl_epmd(3)