[sane-devel] platform independent sanei_usb control messages

[Bertrik Sikken]

Hi all,

I'm working on a backend for scanners based on the 'niash' chipset, 
found in scanners like
the HP3300, HP3400, HP4300, (HP5400?) and the Agfa Snapscan Touch.

Until now I've used libusb to provide platform independent USB access 
which works
mostly fine. I know there's also the sanei_usb functions, but I have 
some issues using them.

When I do a control transfer I need to pass some parameters involving 
(for example)
USB_TYPE_VENDOR, USB_RECIP_DEVICE and USB_DIR_IN which
are defined in linux/usb.h, obviously not platform independent.
I see that the canon630u backend solved this by defining those symbols 
locally.

I suspect that the symbols mentioned above are really part of the USB 
specification,
so they are not platform specific. Maybe it's a good idea to add them to 
sanei_usb.h?

What is actually the preferred USB access method for SANE?
And for what reasons?

Kind regards,
Bertrik Sikken