Chmod change access permissions of a file #include <modes.h> chmod char *fname int perm Chmod changes the permission bits associated with a file. "Fname" must be a pointer to a file name, and "perm" should contain the desired bit pattern, The allowable bit patterns are defined in the include file as follows: /* permissions */ #define S_IREAD 0x01 /* owner read */ #define S_IWRITE 0x02 /* owner write */ #define S_IEXEC 0x04 /* owner execute */ #define S_IOREAD 0x08 /* public read */ #define S_IOWRITE 0x10 /* public write */ #define S_IOEXEC 0x20 /* public execute */ #define S_ISHARE 0x40 /* sharable */ #define S_IFDIR 0x80 /* directory */ Only the owner or the super user may change the permissions of a file. A successful call returns 0. A -1 is returned if the caller is not entitled to change permissions of "fname" cannot be found. OS-9 command "attr"