chmod()                 Change File Permission Setting

 #include   <io.h>
 #include   <sys\stat.h>

 int        chmod(pathname, pmode);
 const char *pathname;                   Name of file
 int        pmode;                       Permission setting

    chmod() changes the permission setting of the file specified by
    'pathname'. The permission setting controls whether the file has
    read-only or read and write access. To change the permission setting,
    set the 'pmode' value to:

                 S_IWRITE              for write permission
                 S_IREAD               for read permission
                 S_IREAD | S_IWRITE    for read and write permission

       Returns:     0, if successful. On error, -1 is returned and
                    'errno' is set to ENOENT (file not found), or EACCES
                    (permission denied).

         Notes:     Under MS-DOS all files are readable; you cannot have
                    a write-only file. If write permission is not
                    specified, the file is made read-only.

   -------------------------------- Example ---------------------------------

    The following statements change the file to read-only status:

           #include <sys\stat.h>
           #include <io.h>

           int result;

           main()
           {
               result = chmod("invoice.bak", S_IREAD);
               if (result == -1)
                  perror("can't change permission mode");
           }