OPEN(2)                                                   OPEN(2)

          open - open for reading or writing

          open(name, mode)
          char *name;

          Open opens the file name for reading (if mode is 0), writing
          (if mode is 1) or for both reading and writing (if mode is
          2).  Name is the address of a string of ASCII characters
          representing a path name, terminated by a null character.

          The file is positioned at the beginning (byte 0).  The
          returned file descriptor must be used for subsequent calls
          for other input-output functions on the file.

          creat(2), read(2), write(2), dup(2), close(2)

          The value -1 is returned if the file does not exist, if one
          of the necessary directories does not exist or is unread-
          able, if the file is not readable (resp. writable), the name
          is too long, or if too many files are open.

          It should be possible to optionally open files for writing
          with exclusive use, and to optionally call open without the
          possibility of hanging waiting for carrier on communication