Apple IIe - Page 219

Cassette
and
Disk Storage with
the
App
le
lie
219
the
file
after an
APPEND
has
been executed,
that
data
will
be
written
immediately
after existing
file
data.
If
an
attempt
is
made
to
read data
from
the
file
after an APPEND
has
been executed,
the
following
error
message
will
be
displayed:
END
OF
DATA
APPEND
performs
an
OPEN
on
the
specified
file
if
that
file
already
exists.
If
the
specified
file
does
not
exist,
the
following
error
message
will
be
displayed:
FILE
NOT
FOUND
In
other
words,
unlike
OPEN, APPEND
will
not
create a
file.
POSITION
POSITION
can be used
to
move
the
file
pointer
to
any given
field
in
the
sequential file.
Configuration
POSITION
filename
[
,
Rxx]
filename
specifies
the
file
whose
file
pointer
is
to
be
moved. R
indicates
the
relative field
position
, and
xx
indicates
the
number
of
fields
to
be
moved forward.
(POSITION
can
only
be
used
to
move
the
file
pointer
forward).
If
xx=
0,
then
any READ
or
WRITE
operation
will
be undertaken
in
the
current
field.
If
xx=
1,
the
current
field
will
be skipped
over
, and any READ
or
WRITE
operations
will
be
undertaken
in
the
next
field.
If
xx=
2,
the
current
field
and
the
following
field
will
be skipped,
before
any READ
or
WRITE
operat
i
on
will
occur.
A
file
must have been
OPEN
'ed
before
POSITION
can be
executed. Since
OPEN
sets
the
file
pointer
to
the
beginning
of
the
file
,
if
POSITION
is
executed
immediately
after
OPEN
,
the
Rxx parameter
will
select
the
absolute field
position wi
thin
the
file
.
In
other
words
,
the
relative
file
position
(selected
by
R)
will