CHMOD(2)            UNIX Programmer's Manual             CHMOD(2)

NAME
     chmod - change mode of file

SYNOPSIS
     chmod(name, mode)
     char *name;

DESCRIPTION
     The file whose name is given as the null-terminated string
     pointed to by _n_a_m_e has its mode changed to _m_o_d_e.  Modes are
     constructed by ORing together some combination of the fol-
     lowing:

           04000 set user ID on execution
           02000 set group ID on execution
           01000 save text image after execution
           00400 read by owner
           00200 write by owner
           00100 execute (search on directory) by owner
           00070 read, write, execute (search) by group
           00007 read, write, execute (search) by others

     If an executable file is set up for sharing (-n or -i option
     of _l_d(1)) then mode 01000 prevents the system from abandon-
     ing the swap-space image of the program-text portion of the
     file when its last user terminates.  Thus when the next user
     of the file executes it, the text need not be read from the
     file system but can simply be swapped in, saving time.
     Ability to set this bit is restricted to the super-user
     since swap space is consumed by the images; it is only worth
     while for heavily used commands.

     If a directory (for example, /tmp) has the 01000 bit on in
     its mode, only the user himself (or the super-user) may
     delete files he owns from the directory (regardless of other
     ``write'' permissions).

     Only the owner of a file (or the super-user) may change the
     mode.  Only the super-user can set the 01000 mode.

RETURN VALUE
     Upon successful completion, a value of 0 is returned.  Oth-
     erwise, a value of -1 is returned and _e_r_r_n_o is set to indi-
     cate the error.

ERRORS
     _C_h_m_o_d will fail and the file mode will be unchanged if:

     [EINVAL]            The path name contained a non-ASCII
                         byte.

     [ENOTDIR]           A component of the path prefix is not a

Printed 5/23/83                                                 1

CHMOD(2)            UNIX Programmer's Manual             CHMOD(2)

                         directory.

     [ENOENT]            The named file does not exist.

     [EACCES]            Search permission is denied on a com-
                         ponent of the path prefix.

     [EPERM]             The effective user ID does not match the
                         owner of the file and the effective user
                         ID is not the super-user.

     [EROFS]             The named file resdes on a read-only
                         file system.

     [EFAULT]            _N_a_m_e points outside the process's allo-
                         cated address space.

     [ELOOP]             Too many symbolic links were encountered
                         in translating the path name.

SEE ALSO
     chmod(1)

ASSEMBLER
     (chmod = 15.)
     sys chmod; name; mode

Printed 5/23/83                                                 2