POSTIO(1) RISC/os Reference Manual 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 destina-
tion.
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 writ-
ing 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 (stan-
dard 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.
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:
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POSTIO(1) RISC/os Reference Manual POSTIO(1)
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 over-
rides 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 pro-
cess, disables the q option, limits the internal
buffer size to 1024 bytes, can use an excessive
amount of CPU time, and does nothing in interac-
tive mode.
The best performance will usually be obtained by using a
large internal buffer (the B option) and by running the pro-
gram 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 mechan-
ism, so q is disabled and the program runs as a single pro-
cess.
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 Ctrl-T (status query),
Ctrl-C (interrupt), and Ctrl-D (end of job) characters.
When the printer goes IDLE, files are transmitted along with
an occasional Ctrl-T (unless the q option was used). After
all the files are sent the program waits until it's reason-
ably sure the job is complete. Printer generated error
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POSTIO(1) RISC/os Reference Manual POSTIO(1)
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
NOTES
The input files are handled as a single PostScript job.
Sending several different jobs, each with their own internal
end of job mark (Ctrl-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 example, the code needed to connect to a Datakit desti-
nation 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 gen-
erally recommended and should be used only if all other
attempts to establish a reliable connection fail.
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POSTIO(1) RISC/os Reference Manual POSTIO(1)
DIAGNOSTICS
An exit status of 0 is returned if the files ran success-
fully. 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.
SEE ALSO
download(1), dpost(1), postdaisy(1), postdmd(1), postmd(1),
postprint(1), postreverse(1), posttek(1).
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