if banners enabled, how does backend get print job file?

[Helge Blischke]

Ted Tanaka wrote:

> I wrote a custom backend, and it receives the print job via stdin just
> fine when banners are disabled.  But when banners are enabled, the backend
> gets the first banner page as stdin, and the print job and second banner
> page are not processed by the backend.
> 
> Also, they are stored as 3 separate files in /var/spool/cups, so I know
> CUPS is correctly processing the job.
> 
> Can someone tell me how my backend can access both the banner pages and
> the file to be printed?  The backend appears to only be called once for
> the entire print job (2 banner files and user file).
> 
> Thanks!

When printing starts, all three files - preceding banner, user file, 
following banner - are concatenated by the scheduler.

In case of PostScript as the final content-type, each of these parts is 
followed by a CTRL D (0x04), which your backend needs to account for.

An example (created by CUPS 1.4.6; changeover from banner page to user 
file):

%%Trailer
%%Pages: 1
%%BoundingBox: 12 12 583 830
%%EOF
^D%!PS-Adobe-3.0
%%Creator: GPL Ghostscript 905 (ps2write)
%%LanguageLevel: 2
%%CreationDate: D:20120508160948+02'00'


Helge