Example

       #include <unixio.h>
       #include <fcntl.h>
       #include <stdlib.h>

       main()
       {
           int file,
               stat;
           int flags;

           flags = O_
RDWR;  /*  Open for read and write,            */
                            /*  with user default file protection,  */
                            /*  with max fixed record size of 2048, */
                            /*  and a block size of 2048 bytes.     */

       file=open("file.dat", flags, 0, "rfm=fix", "mrs=2048", "bls=2048");
           if (file == -1)
               perror("OPEN error"), exit(1);

           close(file);
       }