postio(1) postio(1)
NAME
postio - serial interface for PostScript printers
SYNOPSIS
postio -l line [options] [files]
DESCRIPTION
postio sends files to the PostScript printer attached to line.
If no files are specified the standard input is sent. The
first group of options should be sufficient for most
applications:
-b speed Transmit data over line at baud rate speed.
Recognized baud rates are 1200, 2400, 4800, 9600,
and 19200. The default speed is 9600 baud.
-l line Connect to the printer attached to line. In most
cases there is no default and postio must be able to
read and write line. If the line doesn't begin with
a / it may be treated as a Datakit destination.
-q Prevents status queries while files are being sent
to the printer. When status queries are disabled a
dummy message is appended to the log file before
each block is transmitted.
-B num Set the internal buffer size for reading and writing
files to num bytes. By default num is 2048 bytes.
-D Enable debug mode. Guarantees that everything read
on line will be added to the log file (standard
error by default).
-L file Data received on line gets put in file. The default
log file is standard error. Printer or status
messages that don't show a change in state are not
normally written to file but can be forced out using
the -D option.
-P string Send string to the printer before any of the input
files. The default string is simple PostScript code
that disables timeouts.
-R num Run postio as a single process if num is 1 or as
separate read and write processes if num is 2. By
default postio runs as a single process.
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postio(1) postio(1)
The next two options are provided for users who expect to run
postio on their own. Neither is suitable for use in spooler
interface programs:
-i Run the program in interactive mode. Any files are
sent first and followed by the standard input.
Forces separate read and write processes and
overrides many other options. To exit interactive
mode use your interrupt or quit character. To get a
friendly interactive connection with the printer
type executive on a line by itself.
-t Data received on line and not recognized as printer
or status information is written to the standard
output. Forces separate read and write processes.
Convenient if you have a PostScript program that
will be returning useful data to the host.
The last option is not generally recommended and should only
be used if all else fails to provide a reliable connection:
-S Slow the transmission of data to the printer.
Severely limits throughput, runs as a single
process, disables the -q option, limits the internal
buffer size to 1024 bytes, can use an excessive
amount of CPU time, and does nothing in interactive
mode.
The best performance will usually be obtained by using a large
internal buffer (the -B option) and by running the program as
separate read and write processes (the -R 2 option).
Inability to fork the additional process causes postio to
continue as a single read/write process. When one process is
used, only data sent to the printer is flow controlled.
The options are not all mutually exclusive. The -i option
always wins, selecting its own settings for whatever is needed
to run interactive mode, independent of anything else found on
the command line. Interactive mode runs as separate read and
write processes and few of the other options accomplish
anything in the presence of the -i option. The -t option
needs a reliable two way connection to the printer and
therefore tries to force separate read and write processes.
The -S option relies on the status query mechanism, so -q is
disabled and the program runs as a single process.
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postio(1) postio(1)
In most cases postio starts by making a connection to line and
then attempts to force the printer into the IDLE state by
sending an appropriate sequence of ^T (status query), ^C
(interrupt), and ^D (end of job) characters. When the printer
goes IDLE, files are transmitted along with an occasional ^T
(unless the -q option was used). After all the files are sent
the program waits until it's reasonably sure the job is
complete. Printer generated error messages received at any
time except while establishing the initial connection (or when
running interactive mode) cause postio to exit with a non-zero
status. In addition to being added to the log file, printer
error messages are also echoed to standard error.
EXAMPLES
Run as a single process at 9600 baud and send file1 and file2
to the printer attached to /dev/tty01:
postio -l /dev/tty01 file1 file2
Same as above except two processes are used, the internal
buffer is set to 4096 bytes, and data returned by the printer
gets put in file log:
postio -R2 -B4096 -l/dev/tty01 -Llog file1 file2
Establish an interactive connection with the printer at
Datakit destination my/printer:
postio -i -l my/printer
Send file program to the printer connected to /dev/tty22,
recover any data in file results, and put log messages in file
log:
postio -t -l /dev/tty22 -L log program > results
NOTICES
The input files are handled as a single PostScript job.
Sending several different jobs, each with their own internal
end of job mark (^D) is not guaranteed to work properly.
postio may quit before all the jobs have completed and could
be restarted before the last one finishes.
All the capabilities described above may not be available on
every machine or even across the different versions of the
UNIX system that are currently supported by the program. For
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postio(1) postio(1)
example, the code needed to connect to a Datakit destination
may work only on System V and may require that the DKHOST
software package be available at compile time.
There may be no default line, so using the -l option is
strongly recommended. If omitted, postio may attempt to
connect to the printer using the standard output. If Datakit
is involved, the -b option may be ineffective and attempts by
postio to impose flow control over data in both directions may
not work. The -q option can help if the printer is connected
to RADIAN. The -S option is not generally recommended and
should be used only if all other attempts to establish a
reliable connection fail.
DIAGNOSTICS
An exit status of 0 is returned if the files ran successfully.
System errors (such as an inability to open the line) set the
low order bit in the exit status, while PostScript errors set
bit 1. An exit status of 2 usually means the printer detected
a PostScript error in the input files.
REFERENCES
download(1), dpost(1), postdaisy(1), postdmd(1), postmd(1),
postprint(1),
postreverse(1), posttek(1)
Copyright 1994 Novell, Inc. Page 4