man(1) Manual page archive

     CHMOD(2)                                                 CHMOD(2)

          chmod, fchmod - change mode of file

          chmod(name, mode)
          char *name;

          fchmod(fd, mode)

          Chmod changes the mode of the file specified by the null-
          terminated string name to mode. Fchmod changes the mode of
          an open file referred to by a file descriptor.  Modes are
          constructed by oring together some combination of the fol-

                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 (this is the
          default) then mode 1000 prevents the system from abandoning
          the swap-space image of the program-text portion of the file
          when its last user terminates.  Ability to set this bit is
          restricted to the super-user since swap space is consumed by
          the images.

          Only the owner of a file (or the super-user) may change the
          mode.  Only the super-user can set the 1000 mode.


          Zero is returned if the mode is changed; -1 is returned if
          name cannot be found or if current user is neither the owner
          of the file nor the super-user.