%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      connecback.hlq
%.AUTHOR     KB, IPG/ESO
%.KEYWORDS   MIDAS, help files, CONNECT/BACK_MIDAS
%.PURPOSE    On-line help file for the command: CONNECT/BACK_MIDAS
%.VERSION    1.0  12-MAR-1990 : Creation, KB
%.VERSION    1.1  22-FEB-1993 : Update, KB
% 050615	last modif
%----------------------------------------------------------------
\se
SECTION./BACK_MIDAS
\es\co
CONNECT/BACK_MIDAS					27-OCT-1994  KB
\oc\su
CONNECT/BACK_MIDAS unit wait_specs b_char method
	connect "command syntax" to another MIDAS 
\us\pu
Purpose:
         Connect to another MIDAS (which will be started if not running yet)
         to execute commands in that MIDAS session from the current MIDAS.
\up\sy
Syntax:
         CONNECT/BACK_MIDAS unit wait_specs b_char method display
\ys\pa
         unit = unit of Midas session we want to connect to;
              if the Midas session runs on another host, `host:unit' must
              be entered, but then the Midas session must be already running
              on that host
\ap\pa
         wait_specs = `nowait' or `wait[,max_wait]' to indicate, if we want
             to wait until the background command terminates or not;
             if `,max_wait' is given, at most max_wait seconds are waited,
             then control is returned to the current MIDAS
\ap\pa
         b_char = character to indicate a background command;
             `bchar,command' will execute the command in the Midas session
             with `unit' given above
\ap\pa
         method = FILES or SOCKETS to define the mechanism used for the
             communication with the "background" MIDAS;
             for FILES simple ASCII files and interrupts are used to
             communicate,
             for SOCKETS the communication is established via Unix sockets;
             defaulted to FILES
\ap\pa
         display = display name in X11 notation if the background MIDAS session
             will be started via the CONNECT command
             the backgr. MIDAS will then be displayed in a terminal window on
             the given display
\ap\sa
See also:
         SHOW/BACK_MIDAS, WAIT/BACK_MIDAS, DISCONNECT/BACK_MIDAS 
         SET/BACKGROUND, CLEAR/BACKGROUND, [BackgroundMidas]
\as\no
Note:  
         This command provides a simple way to enforce execution of commands
         in another Midas session, using the current Midas as client and the
         other (background) Midas as server. Up to 5 background Midas sessions
         can be connected to.
            If `method'=FILES, the Midas session we connect to may or may not
         be in background mode (by executing the command SET/BACKGROUND) and
         must run on the same host. I.e. host:unit is not possible for the
         FILES method.
            If `method'=SOCKETS, the Midas session we connect to must already 
	 be in background mode. If that Midas session is started up by the
         CONNECT/BACK command this is done automatically.
         Important: for the socket method, the `unit' parameter must be two 
         digits, e.g. 33, `unit' like xx will NOT work!!
 
         Also, remote Midas sessions cannot be started via the CONNECT command!
\on\exs
Examples:
\ex
         CONNECT/BACK zk nowait z
           Indicate, that all commands with prefix "z," or "Z," will be 
           executed with the prefix stripped off again in background Midas with
           unit `zk', do NOT wait until that command terminates. ASCII files
           and interrupts will be used as the communication mechanism.
           If a Midas session with unit `zk' does not run yet, it will be
           started first.
           The command: Z,HELP LOAD/IMAGE    would then display the help text
           in the window belonging to the background Midas with unit `zk'.
\xe \ex
         CONNECT/BACK 44 wait b
           Indicate, that all commands with prefix "b," or "B," will be 
           executed (prefix stripped off) in background Midas with unit `44',
           wait until that command terminates. ASCII files and interrupts
           are used as the communication mechanism.
           B,HELP READ/KEY INPUTC  would then display the contents of keyword 
           INPUTC in the window of to the background Midas with unit `44'.
\xe \ex
         CONNECT/BACK 88 wait,10 c
           All commands with prefix "c," or "C," will be executed (with prefix 
           stripped off) in background Midas with unit `88'. ASCII files
           and interrupts are used as the communication mechanism.
           We wait at most 10 seconds for the termination of the command which
           has been sent to MIDAS with unit `88'. If the command has not
           finished by then, control returns and an error message is displayed
           in the current MIDAS.
\xe \ex
         CONNECT/BACK 33 no x sockets xt119:0.0
           All commands with prefix "x," or "X," will be executed in the Midas
           session with unit `33' running on the same host.
           This Midas session will be started using a window on the X-terminal 
           xt119:0.0. Local sockets are used as communication mechanism.
           If this Midas session is already running the `display' parameter is
           ignored.
\xe \ex
         CONNECT/BACK ns2:33 no x sockets 
           All commands with prefix "x," or "X," will be executed in the Midas
           session with unit `33' running on system named `ns2'.
           This Midas session must be already running. Network sockets are used
           as the communication mechanism.
\xe \sxe
