Try this link: http://fossil.wpi.edu/docs/howto_add_systemcall.html but i think it won't be enough, u'll still need to defing an " int errno" in the sys call's wrapper , because the system call will always return the err code in theat errno. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/