How to get backchannel file descriptor

[keens312]

> keens312 wrote:
> > Hi Michael,
> >
> > In the filter for backchannel, I created a thread to keep reading feedback from printer...
> >
> > On OSX 10.5, CUPS has created backchannel FDs for USB and Network backends.
> >
> > The question is how to get the correct file descriptor in filter?
>
> Use the supplied API: cupsBackChannelRead.  The file descriptor itself
> is #3.
>
> --
> ______________________________________________________________________
> Michael R Sweet                        Senior Printing System Engineer
>
To support OSX 10.3.9, I don't use cupsBackChannelRead.

I am going to use fixed FD #3 for backchannel, hoping this FD will never be changed.

Thanks
Keene