Hi again, On Wednesdayen den 16 July 2008 02:02:36 K?re S?rs wrote: > Hi, > > I'm a bit confused with the use of sane_cancel(). I noticed today that the > pixma backend requires a sane_cancel after each scan (libksane did not work > correctly with the pixma backend). I have read here on the list: > "5. be aware that a proper front-end in batch mode will call > sane_start() at the beginning of each page, but only call sane_cancel > after the last page returns SANE_STATUS_NO_DOCS." > > Why does the frontend have to call sane_cancel() at the end of a scan? > > Is this a bug in the pixma backend (libksane works OK with at least the > test, epson, epkowa and v4l backends), or is the pixma backend just more > strict than the backends I have tested with before? (The problem was that > the backend did not accept writes to any parameters after a scan without a > cancel at the end.) > > I remember reading something about clarifying the use of sane_cancel() in > the standard for 1.1, but I can't remember what it was about :) >
Reading the standard again I see in 4.4 "Note that sane_cancel() must be called even if the last read operation returned SANE_STATUS_EOF." But I'm still wondering why :) -- K?re S?rs
