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Linux 2.6 - man page for slave (linux section 3erl)

slave(3erl)			     Erlang Module Definition			      slave(3erl)

NAME
       slave - Functions to Starting and Controlling Slave Nodes

DESCRIPTION
       This  module provides functions for starting Erlang slave nodes. All slave nodes which are
       started by a master will terminate automatically when the master terminates. All TTY  out-
       put  produced  at the slave will be sent back to the master node. File I/O is done via the
       master.

       Slave nodes on other hosts than the current one are started with the  program  rsh  .  The
       user  must  be  allowed	to rsh to the remote hosts without being prompted for a password.
       This can be arranged in a number of ways (refer to the rsh documentation for  details).	A
       slave node started on the same host as the master inherits certain environment values from
       the master, such as the current directory and the environment variables. For what  can  be
       assumed about the environment when a slave is started on another host, read the documenta-
       tion for the rsh program.

       An alternative to the rsh program can be specified on the command line to erl as  follows:
       -rsh Program .

       The  slave node should use the same file system at the master. At least, Erlang/OTP should
       be installed in the same place on both computers and the same version of Erlang should  be
       used.

       Currently, a node running on Windows NT can only start slave nodes on the host on which it
       is running.

       The master node must be alive.

EXPORTS
       start(Host) ->
       start(Host, Name) ->
       start(Host, Name, Args) -> {ok, Node} | {error, Reason}

	      Types  Host = Name = atom()
		     Args = string()
		     Node = node()
		     Reason = timeout | no_rsh | {already_running, Node}

	      Starts a slave node on the host Host . Host names need not necessarily be specified
	      as  fully qualified names; short names can also be used. This is the same condition
	      that applies to names of distributed Erlang nodes.

	      The name of the started node will be Name@Host . If no name is provided,	the  name
	      will  be	the  same  as the node which executes the call (with the exception of the
	      host name part of the node name).

	      The slave node resets its user process so that all terminal I/O which  is  produced
	      at the slave is automatically relayed to the master. Also, the file process will be
	      relayed to the master.

	      The Args argument is used to set erl command line arguments.  If	provided,  it  is
	      passed to the new node and can be used for a variety of purposes. See erl(1)

	      As  an  example, suppose that we want to start a slave node at host H with the node
	      name Name@H , and we also want the slave node to have the following properties:

		* directory Dir should be added to the code path;

		* the Mnesia directory should be set to M ;

		* the unix DISPLAY environment variable should be set to the display of the  mas-
		  ter node.

	      The following code is executed to achieve this:

	      E = " -env DISPLAY " ++ net_adm:localhost() ++ ":0 ",
	      Arg = "-mnesia_dir " ++ M ++ " -pa " ++ Dir ++ E,
	      slave:start(H, Name, Arg).

	      If  successful, the function returns {ok, Node} , where Node is the name of the new
	      node. Otherwise it returns {error, Reason} , where Reason can be one of:

		timeout :
		  The master node failed to get in contact with the slave node. This  can  happen
		  in a number of circumstances:

		  * Erlang/OTP is not installed on the remote host

		  * the file system on the other host has a different structure to the the master

		  * the Erlang nodes have different cookies.

		no_rsh :
		  There is no rsh program on the computer.

		{already_running, Node} :
		  A node with the name Name@Host already exists.

       start_link(Host) ->
       start_link(Host, Name) ->
       start_link(Host, Name, Args) -> {ok, Node} | {error, Reason}

	      Types  Host = Name = atom()
		     Args = string()
		     Node = node()
		     Reason = timeout | no_rsh | {already_running, Node}

	      Starts  a slave node in the same way as start/1,2,3 , except that the slave node is
	      linked to the currently executing process. If that process  terminates,  the  slave
	      node also terminates.

	      See start/1,2,3 for a description of arguments and return values.

       stop(Node) -> ok

	      Types  Node = node()

	      Stops (kills) a node.

       pseudo([Master | ServerList]) -> ok

	      Types  Master = node()
		     ServerList = [atom()]

	      Calls pseudo(Master, ServerList) . If we want to start a node from the command line
	      and set up a number of pseudo servers, an Erlang runtime system can be  started  as
	      follows:

	      % erl -name abc -s slave pseudo klacke@super x --

       pseudo(Master, ServerList) -> ok

	      Types  Master = node()
		     ServerList = [atom()]

	      Starts  a  number  of pseudo servers. A pseudo server is a server with a registered
	      name which does absolutely nothing but pass on all message to the real server which
	      executes	at  a  master node. A pseudo server is an intermediary which only has the
	      same registered name as the real server.

	      For example, if we have started a slave node N and want  to  execute  pxw  graphics
	      code  on	this  node,  we can start the server pxw_server as a pseudo server at the
	      slave node. The following code illustrates:

	      rpc:call(N, slave, pseudo, [node(), [pxw_server]]).

       relay(Pid)

	      Types  Pid = pid()

	      Runs a pseudo server. This function never returns any value and the  process  which
	      executes	the  function will receive messages. All messages received will simply be
	      passed on to Pid .

Ericsson AB				  stdlib 1.17.3 			      slave(3erl)


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