net_adm(3)

NAME
net_adm - Various Erlang Net Administration Routines

DESCRIPTION

This module contains various network utility functions.

EXPORTS

dns_hostname(Host) -> {ok, Name} | {error, Host}

    Types
        Host = atom() | string()
        Name = string()

    Returns the official name of Host , or {error, Host} if no such name is found. See also inet(3) .

host_file() -> Hosts | {error, Reason}

    Types
        Hosts = [Host]
        Host = atom()
        Reason = term()

    Reads the .hosts.erlang file, see the section Files below. Returns the hosts in this file as a list, or returns {error, Reason} if the file could not be read. See file(3) for possible values of Reason .

localhost() -> Name

    Types
        Name = string()

    Returns the name of the local host. If Erlang was started with the -name command line flag, Name is the fully qualified name.

names() -> {ok, [{Name, Port}]} | {error, Reason}
names(Host) -> {ok, [{Name, Port}]} | {error, Reason}

    Types
        Name = string()
        Port = int()
        Reason = address | term()

    Similar to epmd -names , see epmd(1) . Host defaults to the local host. Returns the names and associated port numbers of the Erlang nodes that epmd at the specified host has registered.

    Returns {error, address} if epmd is not running. See inet(3) for other possible values of Reason .

    (arne@dunn)1> net_adm:names().
    {ok,[{"arne",40262}]}

ping(Node) -> pong | pang

    Types
        Node = node()

    Tries to set up a connection to Node . Returns pang if it fails, or pong if it is successful.

world() -> [node()]
world(Arg) -> [node()]

    Types
        Arg = silent | verbose

    This function calls names(Host) for all hosts which are specified in the Erlang host file .hosts.erlang , collects the replies and then evaluates ping(Node) on all those nodes. Returns the list of all nodes that were, successfully pinged.

    Arg defaults to silent . If Arg == verbose , the function writes information about which nodes it is pinging to stdout.

    This function can be useful when a node is started, and the names of the other nodes in the network are not initially known.

    Failure: {error, Reason} if host_file() returns {error, Reason} .

world_list(Hosts) -> [node()]
world_list(Hosts, Arg) -> [node()]

    Types
        Hosts = [Host]
        Host = atom()
        Arg = silent | verbose

    As world/0,1 , but the hosts are given as argument instead of being read from .hosts.erlang .

FILES

The .hosts.erlang file consists of a number of host names written as Erlang terms. It is looked for in the current work directory, the user's home directory, and $OTP_ROOT (the root directory of Erlang/OTP), in that order.

The format of the .hosts.erlang file must be one host name per line. The host names must be within quotes as shown in the following example:

^ (new line)