[cups.general] Filer order.

[Michael Sweet]

On Sep 18, 2009, at 10:22 PM, Dyna wrote:
> ...
> May I ask where I can get info about the port monitor? There is a  
> few lines in the "PPD File Syntax" page. But it looks more to be  
> about monitoring the printer i.e. that its up and running or not.

Not exactly.  Port monitors typically do interface-specific encoding  
of the print data; this may also allow for status monitoring, but that  
is usually done by the driver filter or backend.

Here is some documentation:

     http://www.cups.org/documentation.php/doc-1.4/spec-design.html
     http://www.cups.org/documentation.php/doc-1.4/api-filter.html
     http://www.cups.org/documentation.php/doc-1.4/spec-ppd.html#cupsPortMonitor

> I was looking at that but the in the printers.conf listing it as a  
> 1.4 only option. In the "PPD File Syntax" page cupsPreFilter is  
> listed as 1.3 and above option. I assume this is not a typo and I  
> can use cupsPreFilter  with the cups 1.3.9 I'm currently running.

Yes.  The printers.conf information is used for caching the values in  
the PPD file (1.3 and earlier loaded the PPD file every time the  
scheduler started or restarted...)

> Now, it makes me asking what do you need to specify in the  
> printers.conf? What good does the filters do in printers.conf. Sorry  
> it might be a silly question.

It is just caching the values from the PPD file.  You NEVER want to  
edit the printers.conf file directly as a) the format is subject to  
change and b) you need to stop cupsd, make the changes, and start  
cupsd to make the changes stick.

___________________________________________________
Michael Sweet, Senior Printing System Engineer