out-of-band data

Hi List,

I just wonder how an out-of-band condition is defined? QNX online docs state
that “the definition of out-of-band data depends on teh resource manager”.
But I don’t know how.

I am writing a resource manger for a serial printer. When the printer has
fault or error, I expect one or more units of out-of-band data should be
availabe. But it didn’t seem to happen as my client code
ionotify(fd, action, _NOTIFY_COND_OBAND, NULL)
didn’t get this condition.

Should I set up something to make out-of-band data happen? Thanks for your

Best Regards,