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TOGEOMVIEW(1gv)						       TOGEOMVIEW(1gv)

       togeomview - send commands or OOGL objects to geomview

       togeomview [-c] [-g]  [pipename	[program args ...]]

       togeomview  sends a stream of geomview commands,	or OOGL-format geomet-
       ric data, to a cooperating copy of geomview.  If	geomview is  not  run-
       ning, it	is automatically started.  ('geomview' must be on the $PATH of
       the user	running	'togeomview' in	order for this to work.)

       Typical usage is:
	    someprogram	| togeomview	(to send commands) or
	    someprogram-generating-OOGL-data | togeomview -g  (to send geometry)
       i.e. a program pipes geometric data into	``togeomview'';	 the  data  is
       displayed  by  a	 copy  of  geomview  run with the -M option and	a name
       matching	the one	given to togeomview.

       Togeomview uses a named pipe in the directory /tmp/geomview to communi-
       cate with geomview.  If unspecified, the	pipe's default name is "OOGL".
       When sending geometry (-g), a geomview object with the same name	as the
       pipe appears in geomview's object browser.

       By  default,  when  no suitable copy of geomview	is running, togeomview
       invokes "geomview" with	arguments  specifying  the  appropriate	 named
       pipe.  A	different command may be specified as in:

	    togeomview	OOGL  gv -wpos 300x300 -c my_startup_script

       which  communicates  through  a pipe named OOGL,	and (if	necessary) in-
       vokes the given gv command.  The	pipe name is required if a command  is

       After  togeomview  has  created it, the named pipe may be written as an
       ordinary	file.  For example, one	could use

	    togeomview pipename	< /dev/null

       to invoke a listening copy of geomview, and then	run  a	program	 which
       simply wrote to /tmp/geomview/pipename.


       The pipe-based communications scheme imposes several restrictions.

       If  no  copy  of	geomview is reading from the pipe, or if geomview gets
       far enough behind, a program writing data  to  ``togeomview''  will  be
       forced to block after sending a few kilobytes.

       Because	of  the	buffering in the pipe, the sender may be substantially
       ahead of	the geomview display.

       If geomview exits, the sending program receives a  write-on-broken-pipe
       (SIGPIPE) signal, which will kill it unless measures are	taken to catch
       or ignore that signal.

       Only one	copy of	geomview can read from a given pipe at a time.	 If  a
       second  copy  attempts  to read from it,	both will probably fail.  It's
       fine to have multiple copies of geomview	reading	from different pipes.

       Note that togeomview will invoke	geomview if no extant copy is  listen-
       ing  to	the relevant pipe; it can't connect to an existing copy	of ge-
       omview started by other means.

       geomview(1), oogl(5)

Geometry Center			  21 May 1993		       TOGEOMVIEW(1gv)


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