TOGEOMVIEW(1) Geometry Center (21 May 1993) TOGEOMVIEW(1)
NAME
togeomview - send commands or OOGL objects to geomview
SYNOPSIS
togeomview [-c] [-g] [pipename [program args ...]]
DESCRIPTION
togeomview sends a stream of geomview commands, or OOGL-
format geometric data, to a cooperating copy of geomview.
If geomview is not running, it is automatically started.
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 communicate 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) invokes the given gv command. The pipe name is
required if a command is specified.
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.
FILES
/tmp/geomview
BUGS
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
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TOGEOMVIEW(1) Geometry Center (21 May 1993) TOGEOMVIEW(1)
``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 listening to the relevant pipe; it can't connect to an
existing copy of geomview started by other means.
SEE ALSO
geomview(1), oogl(5)
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