OPEN
====

Function
--------

**OPEN** opens file for I/O

Syntax
------

OPEN "file name" FOR {OUTPUT|APPEND|INPUT} AS file no.

Example
-------

::

   10 OPEN "OUTFIL.TXT" FOR OUTPUT AS 1

This will open the file "OUTFIL.TXT" for output from a Basic program as
file number one.

::

   10 OPEN "APPEND.TXT" FOR APPEND AS 3

This opens the file "APPEND.TXT" as file number three. Any data written
to the file will be appended. :doc:`maxfiles` must have
previously been set to a minimum of three.

::

   10 OPEN "INPUT.TXT" FOR INPUT AS 4

The file is opened for input as file number four, this will allow the
data in the file to be read by a Basic program.

Remarks
-------

When a file is OPENed HUNTER'S firmware automatically performs a
checksum generation on the file and compares it to a value stored in the
file directory, when the file was last CLOSEd. Any inconsistency will
result in a 'DSK ERROR' being returned to the user.

The OPEN statement parameter FOR has three options OUTPUT, APPEND and
INPUT, they perform the following functions:

OUTPUT
   This will open a file for output. Any data that is in the file will
   be lost.
APPEND
   This will also open a file for output, but any data that is output to
   the file will be added to the end of the data that is already
   present.
INPUT
   The file is opened for input. This will allow a Basic program to read
   data from the file.

The file number cannot be greater than the number specified in
:doc:`maxfiles`. If MAXFILES 3 has been specified the file
number cannot be greater than three.