[cups.general] Finding out when a job has completed

[Michael Sweet]

On Jul 28, 2009, at 4:35 AM, Tim Waugh wrote:
> I maintain a program that monitors the state of jobs a user has
> submitted for printing.  I'd like it to be able to show a notification
> that the job has completed -- but I need it to really be telling the
> truth.
>
> Is there any way to know for sure that all the pages have been  
> printed,
> and that the ink is now drying on the paper?

Two of the backends support this as part of the protocol (IPP and  
socket), while the others have no way of knowing when the job is  
actually completed.

For non-PS printers, the backend typically doesn't get too far ahead  
of the printer, so a typical home printer probably will be finishing  
the last page when you get the "job completed" notification.

> Even if I can only know this for sure in some very limited
> circumstances, I'd like to know what I need to look for.
>
> I know that IPP provides the job-media-sheets-completed job attribute.
> Can this be relied upon if present, even if the remote IPP
> implementation is a network print server connected to a real printer?


job-media-sheets-completed is updated by PAGE: comments from the  
filters and backends; backends can override the filter-generated  
counts based on what the printer reports, but normally that attribute  
actually tracks how many pages have been sent to the printer...

___________________________________________________
Michael Sweet, Senior Printing System Engineer