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slave(3)		   Erlang Module Definition		      slave(3)

NAME
       slave - Functions for starting and controlling slave nodes.

DESCRIPTION
       This  module  provides  functions  for starting Erlang slave nodes. All
       slave nodes that	are started by a master	terminate  automatically  when
       the  master  terminates.	 All  terminal output produced at the slave is
       sent back to the	master node. File I/O is done through the master.

       Slave nodes on other hosts than the current one are  started  with  the
       rsh  program. The user must be allowed to rsh to	the remote hosts with-
       out being prompted for a	password. This can be arranged in a number  of
       ways  (for details, see the rsh documentation). 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 vari-
       ables. For what can be assumed about the	environment when  a  slave  is
       started on another host,	see the	documentation for the rsh program.

       An  alternative to the rsh program can be specified on the command line
       to erl(1) as follows:

       -rsh Program

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

       A node running on Windows can only start	slave nodes  on	 the  host  on
       which it	is running.

       The master node must be alive.

EXPORTS
       pseudo([Master |	ServerList]) ->	ok

	      Types:

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

	      Calls  pseudo(Master,  ServerList).  If you 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 that does nothing but pass	on all message
	      to  the  real  server  that  executes at a master	node. A	pseudo
	      server is	an intermediary	that only has the same registered name
	      as the real server.

	      For example, if you have started a slave node N and want to exe-
	      cute pxw graphics	code  on  this	node,  you  can	 start	server
	      pxw_server  as a pseudo server at	the slave node.	This is	illus-
	      trated as	follows:

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

       relay(Pid) -> no_return()

	      Types:

		 Pid = pid()

	      Runs a pseudo server. This function never	returns	any value  and
	      the  process  that  executes the function	receives messages. All
	      messages received	are simply passed on to	Pid.

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

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

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

	      Types:

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

	      Starts a slave node on host Host.	Host names need	not  necessar-
	      ily  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 becomes Name@Host. If no name is
	      provided,	the name becomes the same as the  node	that  executes
	      the call (except the host	name part of the node name).

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

	      Argument Args is used to set erl command-line arguments. If pro-
	      vided, it	is passed to the new node and can be used for a	 vari-
	      ety of purposes; see erl(1).

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

		* Directory Dir	is to be added to the code path.

		* The Mnesia directory is to be	set to M.

		* The  Unix  DISPLAY  environment variable is to be set	to the
		  display of the master	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).

	      The function returns {ok,	Node}, where Node is the name  of  the
	      new node,	otherwise {error, Reason}, where Reason	can be one of:

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

		  * Erlang/OTP is not installed	on the remote host.

		  * The	file system on the other host has a  different	struc-
		    ture 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 name Name@Host already exists.

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

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

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

	      Types:

		 Host =	inet:hostname()
		 Name =	atom() | string()
		 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.

	      For   a	description   of  arguments  and  return  values,  see
	      start/1,2,3.

       stop(Node) -> ok

	      Types:

		 Node =	node()

	      Stops (kills) a node.

Ericsson AB			  stdlib 3.8			      slave(3)

NAME | DESCRIPTION | EXPORTS

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