Hi, I am writing a character device driver similar to that in the book LDD3 by rubini.While undersatnding the code I have got some doubt regarding the ioctl implemtntation. In scull.h file it is defined SCULL_IOCTQUANTUM as #define SCULL_IOCTQUANTUM _IO(SCULL_IOC_MAGIC, 3) here while defining there is no arguments for this call. But while implementing that in the ioctl call case SCULL_IOCTQUANTUM: /* Tell: arg is the value */ if (! capable (CAP_SYS_ADMIN)) return -EPERM; scull_quantum = arg; break; but here arg is assigned to scull_quantum.is it the correct?I can nt understand how it is? And wht is the use of capable (CAP_SYS_ADMIN)? will you please help me. thanks in advance, raja -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
