Signaling printer status from a filter

[Michael Sweet]

Josh Mathis wrote:
> Hello Mike,
> 
> Thanks for the information. As I was doing some more reading about these 
> new functions in v1.2, I a little about a port monitor. This sounds like 
> it would be even more ideal, since it can do periodic polling in the 
> background, rather than just during a print job when the other filter is 
> active, giving me momentary rather than historic status. Is that 
> correct? It seems like an idea similar to the Language Monitor in 
> Windows printing. I was unable to find any documentation about the port 
> monitor, other than it exists.

No, the port monitor (currently) only runs when there is a job.  Its
primary purpose is to allow driver developers to support printer-
specific protocol stuff regardless of the type of file that is
printed.  In the future, it may get used for periodic status updates
for a queue...

> Basically, what is the port monitor? Are there any samples available?
> How do they interact with the core CUPS system and other 
> filters/backends? Any information would help.

Look in the monitor subdirectory - you'll find the two standard
port monitors, bcp and tbcp, which are used to support binary
encoding for PostScript printers.  In the future the tbcp port
monitor will also get updated to do page accounting and status
monitoring...

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