"We plan to support/expect our driver to work for only few latest versions of these platforms"
The Sane standard and supporting docs are somewhat dated. I would be surprised if anyone was still building sane on IRIX for instance, so I see your point. However, we have seen many cases of sane being ported to new platforms we did not expect (Windows, Embedded Linux ARM). These efforts were made easier by sane-backends using only simple C, and not requiring lots of external libraries. I daresay, with only a modest effort, you could find simple alternatives to your C++ libraries, since a scanner driver typically does not involve complex code. So, I see no reason to change the rules just yet. allan -- "The truth is an offense, but not a sin"