Filter - backend communication example?

Paul Newall p.newalls at ntlworld.com
Thu Feb 4 15:57:19 PST 2010


>
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> On Feb 4, 2010, at 1:45 PM, Paul Newall wrote:
> >> ...
> > Thank you, That was the roughly kind of thing I was trying. My filter =
> code is like this
> > fp is a FILE pointer to stdout
> >=20
> > 	fprintf(fp, "LockPrinter?");
> > 	fflush(fp);
> >=20
> > Then I do the cupsSideChannelDoRequest call and get CUPS_SC_STATUS_OK
> >=20
> > But fflush(fp); is not causing the packet to be sent to the printer. I =
> still get a large packet, starting with "LockPrinter?" followed by all =
> my subsequent print data.
> >=20
> > My filter, written in c, is set up in a pipeline following ghostscript =
> by a script (maybe that's relevant?)
>
>
> Possibly.  However, it might be more relevant to know which backend you =
> are using...
>
> ___________________________________________________
> Michael Sweet, Senior Printing System Engineer
>

I think the backend is the standard socket backend /usr/lib/cups/backend/socket
Maybe I'll try cutting the filter down to the bare minimum and see what happens.

Paul Newall





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