Talk to printer before a job in CUPS model

[keens312]

Hi Michael,

We can write to stdout and read from backchannel in filter as you said.
But port monitor has a read thread that will keep listening on backchannel.
There are two places to read backchannel feedback, one in filter, the other in port monitor.
So we have to sync them to avoid the race condition.
This sounds complicated.
Is there a better solution for this?
Keene