I have already looked at cffi-grovel, from http://common-lisp.net/project/cffi/manual/html_node/Groveller-Syntax.html#Groveller-Syntax seems that a constant is what i need.

But still not found any examples on how to do the bit mask operations with this constants, it would be great if some body can guide me to the right direction, as i newbie to cffi and cl and i'm missed in the way.

Regards,
Jose
 
Looking at how other projects use cffi seems that i should use a  constant