I think that this time i have included almost every proposed changes.

For the unitTest I did not included the condition "os.getuid() == 0" because of this information in the Linux documentation "3.3 network security issues (capabilities)" http://www.mjmwired.net/kernel/Documentation/networking/can.txt#212. For example, the Ubuntu 10.10 does not require to be root to access socketCAN network interfaces.

For the "return Py_BuildValue("O&h", PyUnicode_DecodeFSDefault, ifname, a->can_family);" i have kept the "h" because in the header file the "a->can_family" is defined as an short int.