Hi, Why can't we define the "container_of" as this? #define container_of(ptr, type, member) \ ( (type *)( (char *)ptr - offsetof(type,member) ) ) Regard, Cheng -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/