[cups.general] Printing multiple copies when file comes from

[Michael Sweet]

Steve Bergman wrote:
> ...
> Oddly, if a filename is specified to lpr, the backend gets called with 
> that filename.

Actually, no.  It gets the job-name attribute in argv[3], which by
default is the basename of the file you are printing.

 > However, if lpr is getting its input from stdin, the backend is
 > told to read from stdin as well,

Not true; printing from stdin is the same from the scheduler's
perspective - you are sending a file (lpr just creates a temp file
when spooling from stdin) and that gets sent to cupsd, which puts
a copy in the spool directory.

 > meaning that multiple copies can never work to a dot matrix, or
 > band printer, or any other printer that does not support multiple
 > copies internally, when lpr gets it's input from stdin.
> 
> This is quite broken behavior and not documented.

Your understanding is completely, totally wrong.

What happens is this:

     1. If you are printing a "raw" (application/vnd.cups-raw)
        file or printing to a queue with no interface script or
        PPD file, then the backend gets the file directly and no
        filtering is done.  The backend is responsible for copy
        generation.

        If the raw file is gzip'd, then CUPS will run the "gziptoany"
        filter which takes care of copy generation, but only for raw
        files.

     2. If you are printing a non-raw file or printing to a queue
        with an interface script or PPD file, then the corresponding
        filters are run and the output is piped into the backend.
        The filters are responsible for copy generation.

This API is, in fact, 99.9% compatible with the traditional SysV lp
interface script mechanism - the 0.1% incompatibility is that we
require the #! stuff on the first line of scripts, but that is a
trivial change to make if you want to use a SysV interface script.

Anyways, copy generation will always work for raw queues, but it
is your responsibility to do copies in your own filters and/or
drivers if the printer doesn't support it.

-- 
______________________________________________________________________
Michael Sweet, Easy Software Products           mike at easysw dot com
Internet Printing and Document Software          http://www.easysw.com