Device Handles

I m trying to get the number of device handles used by a process at a particular instance. I am using x-code on Mac 10.6.6 . I have tried using lsof开发者_如何学运维 but no satisfactory result . Please help.....

You could look in /proc/nnnn/fd/ (where nnn is the pid) but you'd still have to count the files there.