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:
The last option is not generally recommended and should only be used if all else fails to provide a reliable connection:
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.
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.
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:
Establish an interactive connection with the printer at Datakit destination 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:
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.
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.
Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97