John A. Murdie
john at cs.york.ac.uk
Thu Aug 18 11:55:51 PDT 2005
> John A. Murdie wrote:
> > ...
> > Why is 'copies' only decremented if 'ipp' is supplied with a filename
> > (7th argument) - line 835? There's only the one explicit decrement of
> > copies in the 'while (copies > 0)' loop - at line 836.
> If the backend is run without a filename on the command-line, then
> it must (MUST) assume that the upstream filter has prepared the
> necessary number of copies, either by duplicating data or using
> a printer-specific command to do it.
Ah, I see - in this case, copies must be 1. Still, copies never gets decremented if argc == 6, so the explicit loop invariant (copies > 0) is never falsified.
> > (Also, I note that INFO messages are added to the 'Printer History',
> > and not to the CUPS error_log file. Where is the 'Printer History'
> > log kept, and how can I see its accumulated contents?)
> > ...
> The printer history is saved in memory; the most recent state
> change is recorded in printers.conf.
> FWIW, INFO messages are also stored in error_log if the log level
> is "debug2".
Thank you. So under what circumstances is an IPP_GET_JOB_ATTRIBUTES message sent to the printer? (waitjob == 1 in my configuration, by the way.)
I think that lines 840 and 841 should perhaps read:
840 else if (ipp_status == IPP_SERVICE_UNAVAILABLE ||
841 ipp_status == IPP_PRINTER_BUSY)
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